Re: [RE-wrenches] Fed tax credit?

2012-05-17 Thread Joel Davidson
Roof work (including shingles, flashing, strengthening rafters, etc.), 
structural work, civil work (excavating, trenching, etc.), fencing and 
signage, electrical changes and upgrade, design work, permit costs, 
interconnection costs, etc. everything required to install the system should 
be specified in writing so that customers or their accountants can determine 
tax incentives eligibility.


Joel Davidson

- Original Message - 
From: "Dave Click" 

To: "RE-wrenches" 
Sent: Thursday, May 17, 2012 6:38 AM
Subject: Re: [RE-wrenches] Fed tax credit?


It's my understanding that shingles would not be included, just as you
can't build a house and then claim that it's a 5kW PV rack, for an
$80,000 tax credit. The act of installing PV doesn't necessarily require
that the shingles be replaced.

Electrical panel work may be OK if, say, you're putting a 30A PV breaker
in a 100A panel-- the addition of the PV likely requires a change to the
panel to remain code compliant. Similarly, if code requires you to
upgrade the service for your interconnection to be legal, then I would
say that that change is eligible for that ITC.

On 2012/5/17 0:46, Alex Cozine wrote:

To add to the question, what about electrical panel work, or even
service upgrade?




On Wed, May 16, 2012 at 5:17 PM, Jesse Dahl mailto:dahlso...@gmail.com>> wrote:

Hello,

I remember someone asking something kind of similar before, but
couldn't find it in the archives.  Can replacing the shingles be
considered when calculating the total cost of a PV system for
Federal tax credit?

Thanks as always!

Jesse

Sent from my iPad!!!
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--
Alex Cozine
NABCEP Certified Solar PV Installer™
Journeyman Electrician

Brothers Electric Solar
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Re: [RE-wrenches] Transformerless inverters

2012-04-20 Thread Joel Davidson
A Los Angeles contractor replied off-list that transformerless inverters cannot 
get permitted through LA Department of Building & Safety's new express permit 
process that uses boilerplate drawings. They can get permitted through regular 
plan check. This would not be an issue, but LADWP and the LA Department of 
Building & Safety are very influential nationally. They have teamed up to 
spearhead a statewide effort to standardize system designs to expedite 
permitting PV systems under 10 kW. Other utilities have their eyes on what 
LADWP is doing.
Joel Davidson
  - Original Message - 
  From: William Korthof 
  To: re-wrenches@lists.re-wrenches.org 
  Sent: Wednesday, April 18, 2012 11:44 PM
  Subject: Re: [RE-wrenches] RE-wrenches Digest, Vol 5, Issue 113



  Interesting update I've installed dozens of non-isolated transformerless 
inverters 
  with LADWP customers since those genius inverters first became available from 
  Power-One's inverter ancestor, Magnetek. I don't remember ever having a 
conflict or 
  technical issue with an engineer or inspector questioning the suitability of 
that class 
  of inverter, or even looking for the double-insulated solar wire that is 
supposed to be 
  required for the exposed solar wires. 

  /wk


  On 4/16/2012 9:05 AM, Joel Davidson wrote: 
Wrenches, 
Los Angeles Department of Water & Power (LADWP), the largest and most 
influential municipal utility in the US is finally going to allow 
transformerless inverters for residential PV systems. Are there any design, 
installation or reliability issues to consider with the SMA and other 
high-frequency transformerless inverters. Can they be mounted on a hot south or 
west wall or do the have to be kept cool in the shade? 
Joel Davidson 

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[RE-wrenches] Transformerless inverter reliability

2012-04-16 Thread Joel Davidson

Wrenches,
Los Angeles Department of Water & Power (LADWP), the largest and most 
influential municipal utility in the US is finally going to allow 
transformerless inverters for residential PV systems. Are there any design, 
installation or reliability issues to consider with the SMA and other 
high-frequency transformerless inverters. Can they be mounted on a hot south 
or west wall or do the have to be kept cool in the shade?

Joel Davidson

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[RE-wrenches] AC PV module with battery backup?

2012-04-13 Thread Joel Davidson

Wrenches,
I have a customer who wants solar modules and Enphase inverters, but he also 
wants PV and battery backup power during a grid outage. Are any wrenches 
doing this? How? Thanks for sharing your knowledge.

Joel Davidson

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Re: [RE-wrenches] embedded energy in pv

2012-03-16 Thread Joel Davidson
It takes energy to produce, deliver and install PV.

In 1981, Bill Yerkes was asked how much energy is consumed to produce a 
photovoltaic cell. Bill was one of the 3 Spectrolab engineers who developed 
low-cost, single-crystal silicon solar cells in 1974 and founded the company 
that became Arco Solar in 1978. From the September 1981 issue of the Arco Solar 
News: "The major raw material for most solar arrays is silicon in which the 
newer processes consume a total of less than 2 kWh per eventual watt of solar 
array (compared to older processes which consumed about 19 kWh/watt). 
Converting metallurgical grade silicon (97 percent pure) to the high purity 
required for the solar cell remains the major energy investment. Fabricating 
the cell and manufacturing the module adds about 1 kWh per eventual watt of 
solar array-about 30 percent-to the energy investment. This energy investment 
is then returned at the rate of about 2 kWh per watt per year. The energy 
payback period for 1981 solar arrays, using newer processes, is two to three 
years." 

PV production and solar cell efficiency have improved dramatically during the 
past 31 years. See http://www.nrel.gov/docs/fy04osti/35489.pdf

Some people use 180 kWh/day to power their home. And some wrench will use 
gasoline to power their pickup truck to transport people, tools and equipment 
to that home to install PV. Both adversely affect the environment. With patient 
guidance both will improve dramatically over time.

Joel Davidson


  - Original Message - 
  From: toddc...@finestplanet.com 
  To: RE-wrenches 
  Sent: Thursday, March 15, 2012 12:42 PM
  Subject: [RE-wrenches] embedded energy in pv


  i recently read that it takes the equivalent energy of between 1 and 4 tons 
of coal to make a single pv module. this is why i insist my customers do their 
efficiency upgrades and learn how to be frugal/conserve before i will even talk 
about pv with them.



  renewables powering waste is old paradigm thinking.

  consuming less is always a win win.



  unfortunately (now that there is an incentive program) the new "solar 
experts" coming on the scene here make more $$ with bigger systems, so lipstick 
on pigs is becoming the norm.



  one customer wanted pv because her electric bill was over $600.00/month or 
180 kWh/day!! i said there was something wrong with a power bill that high. 
maybe a duct on her heat pump had come loose and was blowing hot air into the 
attic and that should be investigated first with an energy audit. she hired 
another "expert" who put in a massive system. 



  personally, i find it difficult to support this kind of resource use.



  todd











  On Thursday, March 15, 2012 6:26am, "Solarguy"  said:



  William

  Attached is a Power Point slide I made that shows the 'energy payback' from 
PV. The Swiss based IEA Photovoltaic Power Systems Programme takes a very 
serious look at the PV industry and its long term effects on the planet and PV 
is already pretty benign. While I don't know the logic behind their 
calculations my first thought is that with the volume of aluminum being 
extracted and produced for all industry world-wide, the impact by the PV 
industry is probably next to nothing. 

  And using a plastic compound would mean using a crude oil based product which 
is even a bigger environmental blight than aluminum production-imo. 

  Besides, with the PV industries rush to lower prices someone would have 
discovered a cheaper non-metallic replacement for aluminum if it is out there. 
Having worked for many years in the composite/plastics industry I can say that 
the production of a substitute fiber re-enforced compression molded composite 
for PV frames would be more costly than aluminum and most likely still never 
match the rigidity of aluminum. 

  Now if the PV industry trended back to smaller modules a 'plastic' frame 
could become workable but I don't see that moving out of R&D as long as prices 
and margins are so low. And I don't see a corrosion resistant module becoming a 
niche market any time soon unless another "Silicon Energy" type entrepreneur 
decides there is a market. 


  Jim Duncan

  



  -Original Message-
  From: re-wrenches-boun...@lists.re-wrenches.org 
[mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of William Miller
  Sent: Wednesday, March 14, 2012 9:13 PM
  To: RE-wrenches
  Cc: 'RE-wrenches'
  Subject: Re: [RE-wrenches] Installations in High Salt Spray Environments

  Marco:

  Are we in need of a new generation of PV modules with plastic frames?  How 
about frame-less modules on recycled plastic racking?  What is the energy cost 
for aluminum frame modules versus plastic or recycled plastic?  What is the 
energy cost of anodizing aluminum frames and racking?

  There is a need here folks, that is not being filled.  Entrepreneurs, where 
are you

Re: [RE-wrenches] Community says farewell to solar pioneer Gottlieb - Brattleboro Reformer

2012-02-24 Thread Joel Davidson

Dear Richard,

I'll miss you. I still got that 1961 newspaper article with your picture 
when you were a teenager working on the Vanguard satellite solar cells. It's 
around here somewhere. But there is your photo in The New Solar Electric 
Home book on page 369 lifting one more solar panel onto one more roof. 
Thanks for turning so many people onto PV.


Your friend,
Joel Davidson

- Original Message - 
From: 

To: 
Sent: Friday, February 24, 2012 7:05 AM
Subject: [RE-wrenches] Community says farewell to solar pioneer Gottlieb - 
Brattleboro Reformer




For those of you who knew Richard

http://www.reformer.com/localnews/ci_20024575#.T0enKNp5zOw.email

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Re: [RE-wrenches] Absolyte recovery

2012-02-17 Thread Joel Davidson
Chris,

Look for hair-like cracks around the cell terminals. The cracks are failure 
indicators caused by temperature swings. In Malibu California, a 75 kWh, 
48-volt Absolyte battery bank failed after 4 years. Malibu has a very mild 
climate but temperature in the uninsulated equipment room ranged from 40 F in 
winter to 90 F in summer. The PV system is grid connected with battery backup. 
Absolytes were used to replace an IBE battery bank because no one was watering 
the IBE cells. Two years ago, the Absolytes were replaced with a new IBE 
battery bank that is inspected and watered every 6 months.

Joel Davidson

  - Original Message - 
  From: mac Lewis 
  To: RE-wrenches 
  Sent: Friday, February 17, 2012 7:08 AM
  Subject: Re: [RE-wrenches] Absolyte recovery


  Hi Chris,


  I suspect that the charger in the Apollo Inverter/Charger is undersized, 
especially since all of the loads are -48V.  Conversely, the array is very 
oversized and the controllers float most of the time.  The charge controllers 
were working fine last I checked.  It's difficult to access the site right now, 
it includes a 30 mile snow mobile ride.  We intended to put a comprehensive 
remote monitoring system but it didn't get put in before the snow came.  I want 
to get up there and help the system limp along until snow melt when we can do a 
thorough assessment.
  The generator guy went up there and someone had pulled the stop switch on the 
genset.  The battery voltage was around 5V on a 48V bank.  Yikes!


Thanks for the contact info.


  On Thu, Feb 16, 2012 at 2:13 PM, Chris  wrote:

Hi Mac,

We had a cell failure on an Absolyte system we inherited and contacted;

Jeff Lambert 
Product Support and Warranty 
East Penn Mfg. Co., Inc. - Unigy Battery Division 

( Office: (610) 682 – 6361 ext. 2848   | ÈCell: (484) 955 – 2899  |  ÇPage: 
 888-797-8039  (If no answer on Cell)  |  * Email: jlamb...@eastpennunigy.com

Jeff was very helpful.

I do wonder if your charge controllers are getting the array power out to 
the battery bank, was there any damage to them too? Is the Apollo 4048 
inverter/charger doing its job, is it undersized for the size of battery bank?



Sincerely,

Chris Worcester

Solar Wind Works
NABCEP Certified PV Installer
Phone: 530-582-4503
Fax: 530-582-4603
www.solarwindworks.com
ch...@solarwindworks.com
"Proven Energy Solutions"



From: re-wrenches-boun...@lists.re-wrenches.org 
[mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of mac Lewis
Sent: Thursday, February 16, 2012 12:43 PM
To: RE-wrenches
Subject: Re: [RE-wrenches] Absolyte recovery



 Wrenches,



We have inherited a Telecomm system in which the batteries have had a very 
hard life.  A lighting strike knocked the system off line for about 5 months, 
and ground fault dragged the batteries way down about a month ago.  Now, we are 
seeing about 10h of generator run time/day indicating to me that the batteries 
are not holding voltage at all.



  I am uncertain of the exact specs at this moment, but it is a 24 Absolyte 
IIP batteries (5 years old), with a 5 kW array, two Apollo T80HV charge 
controllers and an Apollo 4048 inverter charger.



I don't have experience with these batteries.  Is there any way to try to 
recover these batteries?  Any good contacts with GNB would be useful.



Thanks






  Wrenches,



  We have inherited a Telecomm system in which the batteries have had a 
very hard life.  




  -- 







  Mac Lewis

  "Yo solo sé que no sé nada." -Sócrates









-- 







Mac Lewis

"Yo solo sé que no sé nada." -Sócrates




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  -- 







  Mac Lewis


  "Yo solo sé que no sé nada." -Sócrates





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Re: [RE-wrenches] 110Vac LED resistance to weak grids in developingworld

2012-02-10 Thread Joel Davidson
LED teardown at 
http://www.edn.com/blog/PowerSource/41611-Samsung_LED_light_bulb_teardown_includes_objective_dimming_numbers.php?cid=EDNToday_20120210

  - Original Message - 
  From: Jesse Dahl 
  To: RE-wrenches 
  Sent: Friday, February 10, 2012 5:32 AM
  Subject: Re: [RE-wrenches] 110Vac LED resistance to weak grids in 
developingworld


  I don't know about spikes or grid events, but my home is 3/4 LED and have 
zero complaints.  The warranty on them is a little weak compared to life 
cycle..  All of mine vary in K rating and lumens and work beautifully. 





  Sent from my iPhone

  On Feb 9, 2012, at 7:45 PM, Ray Walters  wrote:


Personally I love my latest LED lights.  They have gotten substantially 
better just in the past year.  We have some 8 watt units in our kitchen that 
illuminate just like a 35 watt halogen, beautiful color rendition, not that 
blue they used to have.  
I especially like my new 1000 lumen spotlight that lights up brighter than 
a car head light in a package slightly larger than the old mini mag flash 
lights.
However, I have no experience with ham radio, or theRF interference issue.  
We're WiFi, and cell at our house.  I do some audio recording, etc. and haven't 
noticed any extra buzz from the several LEDs I have in my basement studio.

Ray

On 2/9/2012 4:54 PM, toddc...@finestplanet.com wrote: 
  i have some personal experience with led light bulbs. i put them outside 
because the cfl floodlights are very s-l-o-w to warm up to full brightness.



  1) leds are still slightly less efficient (lumens per watt) than cfl's

  2) led light bulbs (2 different brands) throw out an ungodly amount of 
rfi... want to listen to a conversation on the 2 meter ham radio or listen to a 
weak fm broadcast station or watch channel 6 on the tee-vee? go shut off the 
led lights off first.



  my conclusion? led light bulbs are not ready for prime time.



  todd (still using my 25+ year old phillips dulux cfls)







  On Thursday, February 9, 2012 1:44pm, "Jim MacDonald" 
 said:



  Hello wrenches



  I am in Central America and looking to suggest customers buy efficient 
LEDs for illumination in their 120V-wired homes, connected to local power grids 
with less-than-desirable power quality.



  I see that so many manus claim long life for the LEDs, in the tens of 
thousands of hours, yet so few if any back it up with a decent warranty.


  Folks are hesitant to make this investment, believing that voltage surges 
or dips could destroy the LEDs.



  Has anyone heard of LED lights' lives ending prematurely due to grid 
events? 

  Would inline surge protectors [something small to be installed 
immediately downstream of the breaker in the home's main panel) be helpful, and 
if so, does anyone have any recommended brands?


  thanks

  Jim MacDonald




  Sent from Finest Planet WebMail.

   

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[RE-wrenches] SMA SWR2500 inverters

2012-02-07 Thread Joel Davidson

Wrenches,
Does someone have any SMA SWR2500 inverters for sale? Please contact me 
off-list.
Thank you very much 


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Re: [RE-wrenches] DC power for LED lighting

2011-12-16 Thread Joel Davidson
Jeff,

I suggest another approach with the LED supplier. See if you can work with 
them. Tell them you can design their product to operate off-grid and that the 
new design will cost them nothing to develop and open up a whole new market for 
them. They make the lights (their expertise) and you design the power for the 
lighting systems (your expertise). I did that with a beautiful outdoor and 
landscape lighting product. See 
http://www.blisslights.com/index.php?option=com_phocagallery&view=category&id=2:blisslights-outdoors&Itemid=99

Joel Davidson

  - Original Message - 
  From: Jeff Yago 
  To: conr...@cape.com ; 'RE-wrenches' 
  Sent: Friday, December 16, 2011 10:24 AM
  Subject: Re: [RE-wrenches] DC power for LED lighting


  I have a local sign company that asked is to provide a solar lighting system 
for a double sided sign they were building for a large retirement community 
entrance.  We have provided many solar lighting systems just like this over the 
years and sent them several examples.  All our systems have been turn-key in 
that we provided the 12 VDC ground mounted LED flood lights with the separately 
pole mounted solar module(S) and battery/controller box.   We "assumed" when we 
told them our system includes the LED lights that they understood that we were 
providing the lighting.  

   

  Unfortunately, when we arrived on the site to install the solar system, they 
said they did not need our LED lights, they wanted us to power the LED lights 
inside the sign.  We opened up the signs and found two 120 VAC electronic LED 
power supplies.  Each was clearly labeled as providing a maximum of 5 amps at 
12 VDC output, and each powered a separate string of about 150 tiny plastic 
"blocks" and each block contained 2 small LED lamps.   We immediately advised 
the client that the solar  system was designed to power our two  12 VDC flood 
lights and we would have to totally tear out what we had just installed and go 
to a much larger system that included an inverter, larger array, 120 VAC timing 
device, and replace the 2 conductor DC underground wiring  with 3-conductor AC 
wire and all  this would really increase $$$.

   

  I said as an alternative, why can't we just cut out the two electronic120 VAC 
input  LED drivers since we are providing well regulated 12 VDC power direct 
from the GEL battery.   He checked with their LED lamp supplier and they said 
they strongly disagree and will void warranty.  Since we are talking about 
almost 300 total LED devices my client is afraid to give us the OK, even though 
we did run them overnight and everything worked just fine.   As I recall, an 
LED needs something in the circuit to limit the amp current, not the voltage 
flowing through it,  or it will just get brighter and brighter and then fail.  
However, I thought almost all strings of separate LED lights already had some 
kind of regulator built into each light block otherwise those near the end of 
the string would be less bright than those near the power source.Is this 
correct??

   

  Finally, if strings of LEDs require some kind of voltage or current 
regulator, I can't believe they all have to run on 120 VAC as indicated by this 
LED manufacturer who offers no alternative.Any LED experts out there that 
can point me to some type of DC-to-DC converter or current  regulator that can 
replace these 120VAC LED drivers?

   

  Thanks,

   

  Jeff Yago

   



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[RE-wrenches] Monitoring 10kW and 30kW PV Systems

2011-12-07 Thread Joel Davidson

Wrenches,
The California Solar Initiative requires performance monitoring and 
reporting service for some PV systems down to as small as 10kW. The CSI 
eligible service providers list keeps growing making it hard to tell who are 
real providers and who are resellers of someone else's service or only 
provide reporting service for their own projects. Your recommendation for a 
reliable, reasonably priced reporting service would be really appreciated. 
Thanks in advance.

Joel Davidson

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Re: [RE-wrenches] Standard sizing

2011-12-07 Thread Joel Davidson

William,

Almost everyone, including manufacturers, wants standard module sizes. There 
are a lot of similar modules, but manufacturers produce different size and 
shape cells (everything from 4-inch square on up and semi-square, round, 
etc.) and customers have different voltage and current needs (everything 
from 18 to 144 cell modules and up). It's like car tires. Lots of sizes and 
models for all different kinds of cars and applications. Our best course of 
action continues to be keep a file of the published module lists. Then ask 
fellow wrenches what replacements will work and where to find them.


Joel Davidson


- Original Message - 
From: "William Miller" 
To: ; "RE-wrenches" 


Sent: Wednesday, December 07, 2011 9:30 AM
Subject: [RE-wrenches] Standard sizing



Friends:

Why can't the industry create a list of standard module sizes, sort of 
like the battery industry has (http://www.rtpnet.org/teaa/bcigroup.html)? 
This would be a big benefit to the consumer and the installer.  If a 
module of Group X size breaks, you are far more likely to find a 
replacement if other manufacturers make modules of the same physical size. 
Then the only challenge is to match electrical characteristics, but if you 
find the same crystal type and cell count, you have succeeded.  Who can we 
advocate to?


William Miller

PS:  I have been saying this for years!

wm


At 09:04 AM 12/7/2011, you wrote:
One or two Matrix/Photowatt PWX1250 needed, new or used, to replace 
shattered module in a school demonstration system from 2005. Odd size and 
shape, matches nothing else. Please reply offlist if you can help.


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Re: [RE-wrenches] SMA Sunny Design temperature/voltage calculations

2011-12-02 Thread Joel Davidson

Howie,

Thank you for speaking up.

SMA, please bring back the old string sizing program. Please.

When John Berdner introduced the SunnyBoy and showed us the spreadsheet (I 
got version X3.13 in 2003), it answered all our temperature, voltage and 
power questions. When the string sizing program went on-line, it literally 
changed system design. You could quickly do what-ifs and try different 
inverter, module and strings to meet site and requirements.


Wrenches speak up. Hopefully SMA will do the right thing and put that 
oldie-but-goodie back on-line.


Fröhliche Weihnachten
Joel Davidson


- Original Message - 
From: "Howie Michaelson" 

To: "RE-wrenches" 
Sent: Thursday, December 01, 2011 9:17 PM
Subject: [RE-wrenches] SMA Sunny Design temperature/voltage calculations


Apropos to the great discussion about temperature voltage calculations,
has anyone else been frustrated by the removal of output information on
the Sunny Design tool compared to the old on-line string sizing
calculator?  It was very useful to me to have the string sizer show the
temperature voltage calculations for low and high temperature - as far as
I know the only string sizing application that showed this info.

The defunct online sizer allowed me to quickly look at a variety stringing
options, see the impact on voltage, narrow down the possibilities and then
run my own voltage calculations to verify.  Sunny Design makes quickly
scanning various string options not so easy, and it buries the results
behind more obscure output info.  It is quite a sophisticated program, but
I wish they gave a way to see the calculations behind the choices it
makes.  Or am I just missing something?

Howie
--
Howie Michaelson
NABCEP Certified Solar PV InstallerT

Catamount Solar, LLC
Renewable Energy Systems Sales and Service
VT Solar Electric & Hot Water Incentive Partner
http://www.CatamountSolar.com
802-272-0004





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Re: [RE-wrenches] calculating low string voltage

2011-11-30 Thread Joel Davidson
...or that most of the time, PV systems do not operate at the array and 
inverter maximum power points...or that test instruments at the best labs are 
only accurate to 3% to 5% (K. Emrey, NREL) which brings to question some of the 
tight module specifications we now see...or that a one-time snapshot is not as 
accurate as a moving picture. Nevertheless, an experienced diagnostician can 
tell if everything (but not necessarily any specific thing) is ok or something 
is amiss.

Joel Davidson
  - Original Message - 
  From: b...@midnitesolar.com 
  To: RE-wrenches 
  Sent: Tuesday, November 29, 2011 10:02 PM
  Subject: Re: [RE-wrenches] calculating low string voltage




  If you really want to throw a monkey wrench into the mix, bring up partial 
shading...

  Or, maybe that's just not allowed in that debate ??Just a thought.

  boB







  On 11/29/2011 8:39 PM, Kent Osterberg wrote: 
Kirk,

You've got some good feedback on this from Ray and Bill. I'll try to add a 
little more. Most module datasheets show a normal operating cell temperature, 
NOCT, value that's typically 47.5°C. That's 20°C ambient temperature, 800 W/sq 
m, and calm wind and nothing blocking the airflow on the back of the module. 
That 27.5°C temperature rise should be pretty close to the temperature rise 
that occurs for a pole-top mount. It's common to see people use 25°C for 
modules on a pole and 30°C or 35°C on a roof and there are data that support 
these "typical" values. With 1000 W/sq irradiance, the temperature rise can 
obviously be more too. Between the intensity of the sun, the direction of the 
sun, the color of the roof, the spacing off the roof, and the wind speed there 
is a lot that is different from one system to the next or even one day to the 
next.

Most PV module spec sheets don't give you a temperature coefficient for 
Vmp. I've seen people use the the Voc coefficient, usually expressed as a 
percentage, for both Voc and Vmp. Big mistake. Data from NREL indicates as Bill 
said, the temperature coefficient for Vmp is higher than that the temperature 
coefficient for Voc. That's particularly true when the coefficient is expressed 
as a percentage per °C. Since there are very few manufacturer's that give both 
temperature coefficients, I'll use a value from an old Evergreen module for an 
example. The Evergreen ES-195 datasheet shows Voc = 30.5 volts with a 
coefficient of -0.34%/°C and Vmp = 27.1 volts with a coefficient of -0.47%/°C. 
Since one shouldn't add volts and percents, I'll put the temperature 
coefficients in volts/°C: Voc = 30.5 V - 0.10 V/°C and Vmp = 27.1 V - 0.13V/°C. 
So Vmp is moving faster than Voc, but not a lot faster. That's generically true 
for c-Si or poly-Si.

Kent Osterberg
Blue Mountain Solar, Inc.
www.bluemountainsolar.com
t: 541-568-4882
On 11/29/2011 11:48 AM, Kirk Herander wrote: 
  I am in debate with a PE over calculation of low voltage of a series 
string on a hot day. He insists that an arbitrary high cell temp is factored 
in, not just ambient temperature. Could someone please give an accepted formula 
for this calculation? Thanks. I cannot find a clear reference to low voltage 
calculation on a hot day (but every reference material is clear on how to 
calculate high voltage on a cold day).



  Kirk Herander

  VT Solar, LLC

  dba Vermont Solar Engineering

  NABCEPTM Certified installer Charter Member

  NYSERDA-eligible Installer

  VT RE Incentive Program Partner




   

 

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Re: [RE-wrenches] Liability

2011-11-23 Thread Joel Davidson
Hello Mac,

I can understand not wanting to get involved in some people's problems, but 
electricians, plumbers and other tradespeople make a good living fixing 
people's problems. I have examined, tested and repaired PV systems for over 25 
years. Sometimes I work with subcontractors or partner up with other experts on 
some jobs. I have never been sued by a client or a subcontractor because I make 
it a point to avoid problem people.

Almost all my problem-solving work comes from phone inquiries, but some come by 
email. I telephone interview the prospect to determine the problem and to get a 
feel for how they will be as a client. I will not work for or with disturbed 
people or trouble-makers. I always ask who did the work and why he or she is 
not fixing it. The prospect's answers tell a lot about how the prospect will be 
as a client.

If I can not do the work and know someone good who can do the work, I make a 
courtesy referral. If I can do what the caller wants or needs, I will tell the 
caller what I will do and how much I will charge. If they agree, I go to the 
site. If I do not feel good about the prospect or the place, I tell them I can 
not help them and leave.

If the prospect is reasonable and I can do the work, I examine what needs to be 
done, show and tell the prospect what I will do, how much it will cost and the 
payment terms. If the client agrees, then in writing I specify the problem, my 
solution, list pre-existing conditions and exclusions for which I am not 
responsible. I also indemnify myself from any and all unspecified and 
undiscovered pre-existing conditions. Then I get the client to agree in writing 
that I will not be held responsible for the listed and undiscovered 
pre-existing conditions and exclusions. Then I do the work.

Upon completion of the work, I show and tell the client what I did and get 
their acknowledgement that I performed the work that they expected to their 
complete satisfaction. If there are any unfinished issues, I finish them to 
their complete satisfaction. Then in writing, I list the work performed, 
reiterate the exclusions, have them sign off that the work is completed to 
their complete satisfaction and give them the invoice.

I am thankful that many customers have become references and friends.

Happy Thanksgiving.
Joel Davidson

  - Original Message - 
  From: mac Lewis 
  To: RE-wrenches 
  Sent: Wednesday, November 23, 2011 8:43 AM
  Subject: [RE-wrenches] Liability


  Hey wrenches,


  Wanted to see what everyone does in a case like I just encountered.  I got a 
call from a tenant for an off-grid system installed by the landlord (supposedly 
an electrician).  I went up there to look at the site and it was a mess.  
System lacked OCPDs, there were gouges in the insulation of the wires, loose 
terminals, nothing ran in conduit, etc...  I was called up there to see why the 
generator was not auto starting.  I got the auto start working, expressed my 
concern to the tenant about the workmanship and left.  Now I'm wondering 
whether I should have touched the system at all.  What would you do?  Is there 
liability here?


  Thanks
  -- 







  Mac Lewis


  "Yo solo sé que no sé nada." -Sócrates





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Re: [RE-wrenches] Convert Grid Tie SW4048 to Backup System; Add New Inverter, AC Coupled

2011-11-22 Thread Joel Davidson
Allan,

Thanks for reprinting the discussion. The retired engineer and his SW4048 are 
still both alive and doing well. Aside from the Trace SW4048 grid-tie low 
dc-to-ac efficiency (~65%), it is still one of the finest inverters ever made. 
In case I outlast my 13 year old SW4048, what new inverter has the same rugged 
durability but higher grid-tie efficiency?

Joel Davidson
  - Original Message - 
  From: Allan Sindelar 
  To: re-wrenches@lists.re-wrenches.org 
  Sent: Tuesday, November 22, 2011 8:07 AM
  Subject: Re: [RE-wrenches] Convert Grid Tie SW4048 to Backup System; Add New 
Inverter, AC Coupled


  Nathan,
  I neither stated nor implied that the SW series could be AC-coupled, because 
I don't know, friend. I have never had reason to try this. The issue was 
discussed on this forum several years ago, and I have found two key posts from 
David Katz of AEE about this topic in my email Wrenches archives. David only 
addresses compatibility with early Sunny Boys. The SW is true modified sine 
waveform, so whether is would be capable of providing a reference signal to 
which a modern grid-tie inverter could latch would be subject to several 
variables, and would likely vary among inverter brands and models. Here's what 
David wrote on 4/15/2005, excerpted:

I have connected Sunny Boy inverters directly to the output of Xantrex SW 
inverters and Outback inverters. It works well. The Sunny Boy operates when it 
sees the SW or Outback output.  Sometimes it shuts off when a large load, like 
a pump is applied to the circuit, because it looks like a grid failure. If the 
SB shuts off, it waits 5 minutes to turn on.  If there is no AC load on the 
system and the SB is supplying power, you will charge the batteries connected 
to the SW.  You need to put a voltage controlled switch to turn of the AC 
between the Sunny Boy and the sub panel if the battery voltage gets too high.

The SW is bi-directional. if you put ac into the output, it charges the 
battery. The AC in terminal is connected directly to the output through a 
relay. The inverter is quite amazing. If you connect the output of the SB and 
the SW to the same sub panel and turn off all loads you will see it charge the 
battery. If you turn on loads to the point you are drawing more than the SB is 
supplying, it will begin to draw power from the battery and supply the excess 
that the SB is not supplying. I use an outback for backup power on my grid 
connected house this way. As long as the SW in turned on, there is a sine wave 
present at the AC output. This makes the SB think the grid is present. I hope 
this answers your question. If not let me know and I will try to draw a 
diagram. 
By the way, if you connect the AC input of the SW or (FX) to a breaker in 
the main panel in a grid connected system it will become your connection from 
the main panel to the sub panel (120VAC) and the inverter will turn on whenever 
the grid fails and keep the SB running. If you are using a 240 V SB, you will 
need an autotransformer or a second SW. 
David 

  You mention the GTI below, but have not indicated whether the SW you are 
considering is or isn't a GTI-equipped model. If it is 4.10/GTI-equipped, I'd 
suspect it's incompatible with AC-coupling. When one of these is not selling 
(such as at night), has no loads on it but is grid-connected, it is continually 
drifting between buy and sell by an amp or two. Note that I have only observed 
this on the SW's meter display, which is a pretty crude measurement. But I 
would expect that this would interfere with any GT inverter's latching 
function, given the mandatory 5-minute waiting period.

  This is all based on observing one system that we installed around 2002 for a 
well-known retired movie star. The system remains fully operational today. We 
had an SW5548 (for most loads) and an SW 4048 (for background loads with surge, 
like pumps) that were not series-stacked, in a GTWB system, small by today's 
standards at 4.4kW of PV. Both inverters had GTIs, but only one was set to 
sell, in order for the two SWs not to argue with each other and to minimize 
their inherent float inefficiency previously noted. 

  I'd guess your chances of AC-coupling would be better with a pre-GTI unit. 
Others here may have had more experience with this question. 

  Just to stir the pot some more, here is an email from Lloyd Gomm, then at 
Xantrex, about the GTI/listing issue from 11/17/2003:

Joel Davidson Wrote: 
  November 15, 2003 one of our customers (maybe more) with a line-tie SW in 
Southern California Edison territory got a notice from Xantrex dated October 
22, 2003 about a required firmware update. Anyone else get this notice? 
Joel, this firmware update is necessary for SW inverters tested / listed by 
UL.  This batch of SW's were produced by Xantrex between Q4 2000 and Q4 2001 
and, to be clear, were de-listed by UL in November 20

Re: [RE-wrenches] Convert Grid Tie SW4048 to Backup System; Add New Inverter, AC Coupled

2011-11-20 Thread Joel Davidson
Wrenches,

I answered Richard off-list, but other wrenches may find this information about 
old SW4048s and batteries useful.

The SW4048 is a solid machine. We've been using one since 1998 and have sold 
hundreds of them for both on and off grid systems. We would leave what's 
working alone and replace and expand the battery bank to meet the client's 
expected grid outage hours. Our system has only 4 kWh of sealed batteries 
because we live in an area that gets almost no power outages and did not want 
to bother watering batteries. See info and wiring diagram at 
http://www.solarsolar.com/oursys.html 

On the other hand, one of our clients in Malibu on the grid had an off-grid 5 
kW PV system for backup power with 75 kWh of IBE flooded lead-acid batteries (2 
parallel strings of 24 each 2-volt cells). We installed the system in 1993 but 
no one maintained the batteries properly. So in 1996 the dead IBE battery bank 
was replaced with a maintenance-free, sealed Absolyte battery bank that only 
lasted 4 years because of 40 F to 90 F temperature swings in the equipment 
room. A few years ago, we upgraded the system with a 31 kW array, 6 Sunny Boys, 
2 Sunny Islands, and went back to a new set of 75 kWh of IBE cells like before. 
Now the batteries are inspected and watered every 2 to 6 months. We are still 
determining the right service period.

I have learned to buy good batteries, install them where the temperature stays 
60 to 70 degrees F. as much as possible, inspect and water flooded batteries at 
least 2 times per year. All things being equal, sealed lead-calcium batteries 
cost twice as much and last half as long as flooded lead-antimony batteries. 
Most importantly, batteries are electro-chemical things just like living 
organisms. Keep them clean, fed (fully charged as much as possible), properly 
watered, at 70 degrees F, don't over-work them (deeply discharged without fully 
charging promptly), and they will last 6 to 8 years easily and often 12 years 
before old-age (high self-discharge) sets in. Battery bank owners that take 
care of themselves, their families, their animals, and their vehicles carry 
those good habits over to taking care of their battery banks. It's sad but true 
that people who are unhealthy and have vehicle problems all the time almost 
always have battery problems.

Best regards,
Joel Davidson



  - Original Message - 
  From: Allan Sindelar 
  To: re-wrenches@lists.re-wrenches.org 
  Sent: Sunday, November 20, 2011 8:21 AM
  Subject: Re: [RE-wrenches] Convert Grid Tie SW4048 to Backup System; Add New 
Inverter, AC Coupled


  Kirk,
  I think there are a couple of subtleties that you're missing in your post. 
All of the SW series that we installed in grid-tied mode prior to Trace/Xantrex 
losing its 1741 listing - mostly Y2K installations - are still in use legally, 
as they were grandfathered in. Once Xantrex lost its listing and went to the 
GTI models (firmware rev. 4.10 and above), only with a GTI were they 1741, and 
the earlier inverters couldn't be retrofit.

  So if Richard's customer's SW4048 is pre-GTI and is currently legitimately 
utility-interactive, it could be argued that it's grandfathered in. Of course, 
I'd avoid arguing anything that esoteric with any governing body. 

  But it's a moot issue anyway. Reviewing the other Wrenches' suggestions, none 
advised continuing to use the SW as an interactive inverter, but only as a 
charging source for a battery bank. One Wrench suggested putting the SW's AC 
input on a weekly timer, which is a good idea. Jay is correct that the SW was a 
terrible inverter for grid-tie. One primary weakness of the SW series was that 
as long as the grid was up, it tried to maintain float voltage to the batteries 
continuously (this was the "lack of silent sell" issue). This brought overall 
sell efficiency down to around 55%, as I recall, rather than the 93+% 
efficiency of today's inverters. But if the inverter is only being used as a 
charging source, it's not selling and thus neither the poor efficiency nor the 
lack of a GTI is relevant.

  Personally, I wouldn't get rid of the SW if the customer wants battery 
backup. The inverters have proven generally reliable, and this one is likely to 
last for decades as an occasional battery charger. Plus it's already paid for, 
and does a good job as both a battery charger and a backup inverter during 
outages. I'd use sealed batteries to deal with the customer's maintenance 
concerns. The Honda 3000i is a good choice at sea level, as the SW can 
hard-limit the AC amp draw from an undersized generator and avoid overloading 
it (and nuisance-tripping its output breaker). But note that the SW can take up 
to about 5,200 watts from an AC source, and sealed batteries prefer high 
charging C/rates, so you might want to use a generator of around 6kW (at 120V) 
instead for bet

Re: [RE-wrenches] Convert Grid Tie SW4048 to Backup System; Add New Inverter, AC Coupled

2011-11-20 Thread Joel Davidson

Where in the NEC is the requirement for the GTI interface?

- Original Message - 
From: "Kirk Herander" 

To: "'RE-wrenches'" 
Sent: Sunday, November 20, 2011 3:33 AM
Subject: Re: [RE-wrenches] Convert Grid Tie SW4048 to Backup System;Add New 
Inverter, AC Coupled




PS - Richard, does it have a Trace / Xantrex GTI interface installed? If
not, it's not code-legal to be tied to the grid anyway. Get rid of the 
4048

whatever you do.

Kirk Herander
VT Solar, LLC
dba Vermont Solar Engineering
NABCEPTM Certified installer Charter Member
NYSERDA-eligible Installer
VT RE Incentive Program Partner


-Original Message-
From: re-wrenches-boun...@lists.re-wrenches.org
[mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Richard L
Ratico
Sent: Friday, November 18, 2011 6:53 PM
To: re-wrenches@lists.re-wrenches.org
Subject: Re: [RE-wrenches] Convert Grid Tie SW4048 to Backup System; Add 
New

Inverter, AC Coupled

Jay, Marv, Chris, Ray, Joel & Maverick,

Thanks tremendously for your input. Each of you provided interesting
suggestions, all of which I find thought provoking and helpful. I greatly
appreciate your taking the time to share your experience.

Dick
Solarwind Electric


--- You wrote:
We redid one in a very similar situation recently. In that case the
customer wanted super backup and so we put in Grid tie Outbacks and a
new battery bank, added modules, and kept the SWs as battery chargers
from the generator. He had the option with bypass switches to use the
SWs, if the Outbacks went out. This guy wanted a "keep the power going,
no matter what" system, but I can't claim that was optimal.  The right
answer depends on what the customer wants.
I probably wouldn't trash everything though as Jay suggested, since the
existing modules are already racked and wired. (unless it's a bogus
install, then yep, salvage it all)
You could probably easily rewire the parallel 48 v sets of modules all
in series in 15 minutes in the combiner box to get the voltage up, and
use a small GT only inverter, too. I guess it would also depend on how
close the 2 different types of modules are in voltage or current, but it
doesn't have to be perfect; as these were modules headed to the scrap
heap otherwise.
In honor of modules that are well installed and still performing
correctly, I do try and reuse them. Being able to brag: "these have been
working for 30 years..." is great for the solar industry as a whole, but
only if it makes sense.

Ray

On 11/17/2011 5:51 PM, jay peltz wrote:

HI Richard,

I'll chime in, although you won't like it.

Dump the system and start over with a new battery less system and a genny

as
back up.


Told you, you wouldn't like it.

The SW parts are basically gone and it was a terrible  grid tied inverter

anyway.

The modules are usable but why at $1.5 watt keep them?
Client doesn't want MX, so that means no batteries.

You'll need a genny as back up anyway for long power outages during

storms, so
get a natural gas/propane unit as back up instead of batteries.


OK you asked,

jay

peltz power
On Nov 17, 2011, at 4:03 PM, Richard L Ratico wrote:


Hi Wrenches,

This is a repost. No replies the first time, so I'm trying one last 
time.


I may be "adopting" an eleven year old, Y2K, grid tie with battery

back-up

system. It consists of 12 - Astro-Power 120 modules, installed in 2000,

12 -

Evergreen  EC-110 modules installed in 2004, only one MX60, which

controls
BOTH

sub-arrays, one SW4048 in SELL mode through a dedicated load sub-panel.
Existing, seven year old battery is shot (8-Trojan L-16). Initial bank 
of

unknown batteries was replaced after only four years.

Recent long, nearby, utility outages have the client requesting a

proposal to

include a new back-up generator and to restore the system selling to the

grid.

Client may decide go straight grid tie to eliminate the batteries. They

have

found the maintenance to be a hassle.

My thoughts so far:

1)To take advantage of most of the existing hardware, I wonder if it

makes
sense

to try to improve the system efficiency by relegating the SW to a manual

back-up

mode only, where, say, by means of a timer controlling grid availability

through
AC1, it would only charge a smaller battery bank once a week. The 
battery

bank

would be small,
a single string of either, sealed gel units or T-105s with the new 
Trojan

watering system.
2) Provide new grid-tie inverter/s (appropriate string type or Enphase

190s)
to

handle the net metering.
3) Provide a way to AC couple the new inverter/s to the SW in the event

of an

outage.
4) Provide a new Honda 3000 inverter type generator connected to AC2 in

the
SW.

5)Provide a way to lockout the grid tie inverter/s when the generator is
operating.

Any thoughts or suggestions would be greatly appreciated.

Thanks in advance,

Dick Ratico
Solarwind Electric
Bradford, VT

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Re: [RE-wrenches] What inverter? (was Faulty PM-60 circuit board)

2011-11-10 Thread Joel Davidson
So far William and Maverick say Enphase 190 and Darryl says Solar Edge. My 
experience is that one SMA inverter costs less and is more reliable than 
multiple inverters.
Joel Davidson
  - Original Message - 
  From: Darryl Thayer 
  To: RE-wrenches 
  Sent: Wednesday, November 09, 2011 8:29 PM
  Subject: Re: [RE-wrenches] What inverter? (was Faulty PM-60 circuit board)


  I think you shoud go with Solar Edge, and modules optimizers


  From: William Miller 
  To: RE-wrenches 
  Sent: Wednesday, November 9, 2011 7:42 PM
  Subject: Re: [RE-wrenches] What inverter? (was Faulty PM-60 circuit board)

  Joel:

  24 Enphase M190s.

  William Miller


  At 09:33 AM 11/9/2011, you wrote:
  >Wrenches,
  >
  >After telling my customer to upgrade to an MPPT charge controller (thanks 
  >Ray Walters and John Blittersdorf), he decided to really optimize his PV 
  >array and retire his Trace SW4048 inverter. He has 48 Siemens SP75 modules 
  >(67.5 W DC PTC) that are ground mounted in full sun and easy to re-wire. 
  >With so many new batteryless grid-tie inverters on the market, this is a 
  >good time to ask this sage group with over 3,000 combined years of 
  >experience what inverter do you prefer?
  >
  >Joel Davidson
  >
  >----- Original Message - From: "Joel Davidson" 
  >
  >To: "RE-wrenches" 
  >Sent: Saturday, November 05, 2011 4:50 PM
  >Subject: Faulty PM-60 circuit board
  >
  >
  >>Wrenches,
  >>
  >>My customer has a circa 2001 Pulse PC250 with a faulty PM-60 circuit 
  >>board TC-750,  REV D2 (the microprocessor U1 has v2.5 and v1.01 written 
  >>on a label on it). Does anyone repair or have replacements for PC250 
  >>PM-60 circuit boards? If not, what do you recommend? Thank you in advance 
  >>for your help.
  >>
  >>Joel Davidson
  >>
  >
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  >19:34:00

  Miller Solar
  Voice :805-438-5600
  email: will...@millersolar.com
  http://millersolar.com
  License No. C-10-773985

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Re: [RE-wrenches] What inverter? (was Faulty PM-60 circuit board)

2011-11-09 Thread Joel Davidson

Hello Ray,

He has had almost no utility power outages since he got his PV system in 
2001. By going batteryless, his dc-to-ac conversion efficiency and kWh 
production should increase by over 15%. He has not decided if he wants to 
keep the SW4048 and float charge his batteries with the grid for emergency 
power.


Joel Davidson

- Original Message - 
From: "Ray Walters" 

To: "RE-wrenches" 
Sent: Wednesday, November 09, 2011 12:59 PM
Subject: Re: [RE-wrenches] What inverter? (was Faulty PM-60 circuit board)



He doesn't want battery backup?

Ray

On 11/9/2011 10:33 AM, Joel Davidson wrote:

Wrenches,

After telling my customer to upgrade to an MPPT charge controller (thanks 
Ray Walters and John Blittersdorf), he decided to really optimize his PV 
array and retire his Trace SW4048 inverter. He has 48 Siemens SP75 
modules (67.5 W DC PTC) that are ground mounted in full sun and easy to 
re-wire. With so many new batteryless grid-tie inverters on the market, 
this is a good time to ask this sage group with over 3,000 combined years 
of experience what inverter do you prefer?


Joel Davidson

- Original Message - From: "Joel Davidson" 


To: "RE-wrenches" 
Sent: Saturday, November 05, 2011 4:50 PM
Subject: Faulty PM-60 circuit board



Wrenches,

My customer has a circa 2001 Pulse PC250 with a faulty PM-60 circuit 
board TC-750,  REV D2 (the microprocessor U1 has v2.5 and v1.01 written 
on a label on it). Does anyone repair or have replacements for PC250 
PM-60 circuit boards? If not, what do you recommend? Thank you in 
advance for your help.


Joel Davidson




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[RE-wrenches] What inverter? (was Faulty PM-60 circuit board)

2011-11-09 Thread Joel Davidson

Wrenches,

After telling my customer to upgrade to an MPPT charge controller (thanks 
Ray Walters and John Blittersdorf), he decided to really optimize his PV 
array and retire his Trace SW4048 inverter. He has 48 Siemens SP75 modules 
(67.5 W DC PTC) that are ground mounted in full sun and easy to re-wire. 
With so many new batteryless grid-tie inverters on the market, this is a 
good time to ask this sage group with over 3,000 combined years of 
experience what inverter do you prefer?


Joel Davidson

- Original Message - 
From: "Joel Davidson" 

To: "RE-wrenches" 
Sent: Saturday, November 05, 2011 4:50 PM
Subject: Faulty PM-60 circuit board



Wrenches,

My customer has a circa 2001 Pulse PC250 with a faulty PM-60 circuit board 
TC-750,  REV D2 (the microprocessor U1 has v2.5 and v1.01 written on a 
label on it). Does anyone repair or have replacements for PC250 PM-60 
circuit boards? If not, what do you recommend? Thank you in advance for 
your help.


Joel Davidson




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Re: [RE-wrenches] Faulty PM-60 circuit board

2011-11-07 Thread Joel Davidson

Hello Ray,

Thank you for the quick reply. You are right. It's time to move on from the 
Pulse stuff. I will recommend this solution to my customer. I did something 
similar to my Trace system when I replaced the C40 that came with the Trace 
Modular Cabinet with an externally mounted Outback MX60, but I did not 
rewire the array.


Best regards,
Joel Davidson


- Original Message - 
From: "Ray Walters" 

To: "RE-wrenches" 
Sent: Monday, November 07, 2011 10:16 AM
Subject: Re: [RE-wrenches] Faulty PM-60 circuit board


Today's controllers are so much better both in terms of battery 
management, and power efficiency, that I replace the old Pulse stuff even 
if they're not dead. I usually keep the PC250 as a DC load center, and pop 
a new controller off the top. This is often a good time to add a few 
modules to the array, and rewire the existing array to higher voltage. 
This allows the existing home run wiring to be reused, even with the 
additional modules. I've found that if the original array wiring was good, 
that it takes very little work to jump up the voltage. Definitely don't 
need to redo every connection.
People are used to upgrading to better electronics: who still uses their 
computer, modem, or cell phone from 10 years ago?
Today's controllers will pay for themselves in extended battery life 
alone.


Ray

On 11/5/2011 6:50 PM, Joel Davidson wrote:

Wrenches,

My customer has a circa 2001 Pulse PC250 with a faulty PM-60 circuit 
board TC-750,  REV D2 (the microprocessor U1 has v2.5 and v1.01 written 
on a label on it). Does anyone repair or have replacements for PC250 
PM-60 circuit boards? If not, what do you recommend? Thank you in advance 
for your help.


Joel Davidson


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[RE-wrenches] Faulty PM-60 circuit board

2011-11-07 Thread Joel Davidson

Wrenches,

My customer has a circa 2001 Pulse PC250 with a faulty PM-60 circuit board 
TC-750,  REV D2 (the microprocessor U1 has v2.5 and v1.01 written on a label 
on it). Does anyone repair or have replacements for PC250 PM-60 circuit 
boards? If not, what do you recommend? Thank you in advance for your help.


Joel Davidson


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Re: [RE-wrenches] Bifacial modules

2011-11-03 Thread Joel Davidson
I also like Bill Brooks' test. I use a Daystar irradiance meter to determine 
light levels through glazing or PV modules by measuring the light throughout 
the day and at the distance from the glazing and height of whatever is being 
illuminated.

  - Original Message - 
  From: Ray Walters 
  To: RE-wrenches 
  Sent: Thursday, November 03, 2011 11:54 AM
  Subject: Re: [RE-wrenches] Bifacial modules


  Geez Joel, we need to start a solar museum for all the cool old stuff you 
have. 
  I just did a bit of research, and it seems lux is a weighted measure based on 
visible light present, while irradiation is more a total power measurement. I 
guess we really need to have two different meters to measure how much light 
passes through a module.
  If we were to go a step further and characterize the quality of light 
present, we might need a spectral analyzer to determine whether its "cool 
white" or "daylight", etc. As always, the more you think about something, the 
more complicated it becomes.

  Ray Walters

  On 11/3/2011 11:39 AM, Joel Davidson wrote: 
See-thru solar cells have been around for decades. Arco Solar made 4% 
efficient amorphous silicon modules and car sunroofs in 1984 that were tinted 
brown like sunglasses. I got a 12-inch square see-thru laminate that still 
works.

I also have a 6.75-inch square sample of MSK Corp's amorphous silicon PV-TV 
solar panels. They were developed in conjunction with Kaneka and Japanese 
architects Taiyo Industries. The full-size glass panels, measure 1-meter 
square. In addition to producing electricity, they provide thermal insulation, 
solar heat gain protection and protection from ultra violet rays. During the 
manufacturing process, a laser inscribes a series of ultra fine lines onto the 
panel to allow 10 percent of visible light to be transmitted through the glass, 
enough for sufficient light to enter a building even during cloudy conditions 
while protecting against excessive solar gain. Amorphous silicon solar cells 
with 10 percent, 5 percent or 1 percent transparency are placed between two 
sheets of glass to generate power. This solar panel is called PV-TV because it 
is also used as a display screen on the outside of buildings. See 
http://www.metropolismag.com/story/20040727/pv-tv-a-multifunctional-eco-friendly-building-material

The Tiger Woods Learning Center in Anaheim and other buildings have 
see-thru Schott solar modules with different amounts of transparency. See 
http://www.solardesign.com/library/pdf/tiger-woods-solar-curtain-wall.pdf

Also, opaque cell solar modules are manufactured with various cell spacings 
for BIPV applications.

I have a Mastech Light Meter LX1010B in my tool kit for measuring lux. This 
handy tool costs around $20.

Joel Davidson


  - Original Message - 
  From: Keith Cronin 
  To: Phil Undercuffler ; RE-wrenches 
  Sent: Wednesday, November 02, 2011 9:50 PM
  Subject: Re: [RE-wrenches] Bifacial modules


  Thanks everyone for the feedback!


  Thinking that the manu's can space cells accordingly on the surface of 
the glass and create whatever % light the end user wants to seep through.


  The % of light must slide between 5-15%, depending on manu's specs. 
Architecture can meet solar and increase the applicability of the products.


  Perhaps someday, they can make the cells see-through (or almost), like 
glass...? Now that opens up possibilities! 

  Aloha,


  Keith


--
  From: Phil Undercuffler 
  To: Keith Cronin ; RE-wrenches 

  Cc: Bill Brooks 
  Sent: Wednesday, November 2, 2011 9:18 AM
  Subject: Re: [RE-wrenches] Bifacial modules


  We've got an array of Silicon Energy modules "out back," and in the 
interests of scientific discovery and procrastinating from what I really am 
supposed to be doing, Kelly, Seth and I just ran a few experiments to see if we 
can quantify the amount of irradiation that makes it through the array. 


  Using a Kyocera module as our reference, we measured ISC with the module 
in the plane of the array, then moved the module to the same orientation but 
approximately 12 feet behind and in the shade of the SE array, and again 
measured ISC.  Sun conditions were light wispy clouds, guesstimated 800 W/M2 
(pretty darned good for Arlington WA this time o' year), 10:30 local time.  We 
measured 5.9A ISC in front of the array, and 610 milliamps when in the shade 
the array, leading us to say that just over 10% of the available sun will make 
it to your orchids.


  It should be noted that there is a opaque backing behind each SE cell, so 
the only light that makes it through is through the intercell gaps.  I've used 
Sanyo doubles before, and in those modules the cells are slightly translucent, 
so the sun is somewhat vis

Re: [RE-wrenches] Bifacial modules

2011-11-03 Thread Joel Davidson
See-thru solar cells have been around for decades. Arco Solar made 4% efficient 
amorphous silicon modules and car sunroofs in 1984 that were tinted brown like 
sunglasses. I got a 12-inch square see-thru laminate that still works.

I also have a 6.75-inch square sample of MSK Corp's amorphous silicon PV-TV 
solar panels. They were developed in conjunction with Kaneka and Japanese 
architects Taiyo Industries. The full-size glass panels, measure 1-meter 
square. In addition to producing electricity, they provide thermal insulation, 
solar heat gain protection and protection from ultra violet rays. During the 
manufacturing process, a laser inscribes a series of ultra fine lines onto the 
panel to allow 10 percent of visible light to be transmitted through the glass, 
enough for sufficient light to enter a building even during cloudy conditions 
while protecting against excessive solar gain. Amorphous silicon solar cells 
with 10 percent, 5 percent or 1 percent transparency are placed between two 
sheets of glass to generate power. This solar panel is called PV-TV because it 
is also used as a display screen on the outside of buildings. See 
http://www.metropolismag.com/story/20040727/pv-tv-a-multifunctional-eco-friendly-building-material

The Tiger Woods Learning Center in Anaheim and other buildings have see-thru 
Schott solar modules with different amounts of transparency. See 
http://www.solardesign.com/library/pdf/tiger-woods-solar-curtain-wall.pdf

Also, opaque cell solar modules are manufactured with various cell spacings for 
BIPV applications.

I have a Mastech Light Meter LX1010B in my tool kit for measuring lux. This 
handy tool costs around $20.

Joel Davidson


  - Original Message - 
  From: Keith Cronin 
  To: Phil Undercuffler ; RE-wrenches 
  Sent: Wednesday, November 02, 2011 9:50 PM
  Subject: Re: [RE-wrenches] Bifacial modules


  Thanks everyone for the feedback!


  Thinking that the manu's can space cells accordingly on the surface of the 
glass and create whatever % light the end user wants to seep through.


  The % of light must slide between 5-15%, depending on manu's specs. 
Architecture can meet solar and increase the applicability of the products.


  Perhaps someday, they can make the cells see-through (or almost), like 
glass...? Now that opens up possibilities! 

  Aloha,


  Keith


--
  From: Phil Undercuffler 
  To: Keith Cronin ; RE-wrenches 

  Cc: Bill Brooks 
  Sent: Wednesday, November 2, 2011 9:18 AM
  Subject: Re: [RE-wrenches] Bifacial modules


  We've got an array of Silicon Energy modules "out back," and in the interests 
of scientific discovery and procrastinating from what I really am supposed to 
be doing, Kelly, Seth and I just ran a few experiments to see if we can 
quantify the amount of irradiation that makes it through the array.


  Using a Kyocera module as our reference, we measured ISC with the module in 
the plane of the array, then moved the module to the same orientation but 
approximately 12 feet behind and in the shade of the SE array, and again 
measured ISC.  Sun conditions were light wispy clouds, guesstimated 800 W/M2 
(pretty darned good for Arlington WA this time o' year), 10:30 local time.  We 
measured 5.9A ISC in front of the array, and 610 milliamps when in the shade 
the array, leading us to say that just over 10% of the available sun will make 
it to your orchids.


  It should be noted that there is a opaque backing behind each SE cell, so the 
only light that makes it through is through the intercell gaps.  I've used 
Sanyo doubles before, and in those modules the cells are slightly translucent, 
so the sun is somewhat visible through the body of the cell itself as well -- 
sort of like looking through very dark sunglasses.  In either case, the 
illumination on objects behind the array is a dappled, dynamic light.  As Bill 
says, it's pretty cool from an aesthetic point of view.  My personal .02 is 
that there is no finer place to put an array than a shade structure using clear 
modules.  It keeps everything off the roof, gives shade and makes for a premium 
installation option.

  Phil
  ---
  "When we learn how to store electricity, we will cease being apes ourselves; 
until then we are tailless orangutans. You see, we should utilize natural 
forces and thus get all of our power. Sunshine is a form of energy, and the 
winds and the tides are manifestations of energy.  Do we use them? Oh, no! We 
burn up wood and coal, as renters burn up the front fence for fuel. We live 
like squatters, not as if we owned the property.  


  There must surely come a time when heat and power will be stored in unlimited 
quantities in every community, all gathered by natural forces."
  -- Thomas Edison --




  On Tue, Nov 1, 2011 at 7:48 PM, Keith Cronin  wrote:

Bill


Appreciate

[RE-wrenches] Low-power consuming LEDs

2011-10-26 Thread Joel Davidson

Wrenches,
Who is a good supplier of low-power consuming individual LEDs. Thank you 
very much for your recommendations.

Best regards,
Joel Davidson

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[RE-wrenches] 6-volt, 10-watt solar module?

2011-10-10 Thread Joel Davidson

Hello Wrenches,
I need a 6-volt approximate 10-watt solar module and a 6-volt charge 
controller and timer similar to the Morningstar 12-volt SL-10L-12V. Thanks 
in advance for your recommendations.

Best regards,
Joel Davidson

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Re: [RE-wrenches] Solar gathering?

2011-10-08 Thread Joel Davidson

Dear Jesse,

1. Go to the Dallas solar exhibition and spend a lot of time on the floor 
talking to real engineers with field experience (not salespeople). First 
question to ask is "How many PV systems have you installed?" Anyone with 
less than 50 systems under their belt is either reading from the book or 
still in training.


2. Attend a Bill Brooks training session. Bill has strong opinions that some 
wrenches disagree with but has seen more PV installations than over 99% of 
the people on Earth and has spend decades thinking about what is good and 
bad PV.


3. Meet with and walk the exhibit floor with and talk shop day and night 
with as many wrenches as you can (at least 3 a day).


4. Go to the exhibits all the time they are open and keep your ears open. 
Wrenching is parts and the people who put parts together. Only go to 
sessions and workshops when the exhibits are closed.


5. Don't become a true believer in any one part or one way to put parts 
together. There are many good and bad parts and techniques. The quest is 
finding something better.


Have fun.
Joel Davidson
"Not all change is for the better, but nothing gets better without change."

- Original Message - 
From: "Jesse Dahl" 

To: "RE-wrenches" 
Sent: Saturday, October 08, 2011 7:56 AM
Subject: [RE-wrenches] Solar gathering?



All,

I am looking for advice on a trade show or continuing Ed classes to attend 
in the future.  I have around $1800 to spend on this endeavor.


Any suggestions?

Thanks as always,

Jesse

Sent from my iPhone
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Re: [RE-wrenches] Home Depot solar?

2011-09-29 Thread Joel Davidson
Solar Electrical Systems (SES) in Westlake Village California was a Home 
Depot installer for BP Solar systems for a few years. SES does excellent 
work. SES no longer installs BP Solar or Home Depot systems but occasionally 
replaces BP modules that fail on the systems that they installed.


Joel Davidson

- Original Message - 
From: "Jesse Dahl" 

To: "RE-wrenches" 
Sent: Thursday, September 29, 2011 7:39 AM
Subject: [RE-wrenches] Home Depot solar?



Anyone out there have any experience with Home Depot's solar installers?

Jesse

Sent from my iPhone
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Re: [RE-wrenches] Suniva

2011-09-12 Thread Joel Davidson
Hello Keith,

I have not bought Suniva cells or modules, but I know that Dr. Ajeet Rohatgi, 
founder and CTO, is one of the world's top PV scientists and US and Asian cell 
customers are lined up waiting to buy their cells.

Joel Davidson

  - Original Message - 
  From: Keith Cronin 
  To: RE-Wrenches 
  Sent: Monday, September 12, 2011 3:08 PM
  Subject: [RE-wrenches] Suniva


  Folks- any of you purchased any of these?


  http://suniva.com/index.php


  Aloha,


  Keith


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Re: [RE-wrenches] unique battery bank design question

2011-09-02 Thread Joel Davidson
On T-105 battery banks, I've used taps with alligator clips so the tap could 
be moved every few days to power 1 amp or less loads. The taps worked 
because I equalized the battery bank every month. I've used voltage-dropping 
resistors (simple and cheap), Vanner equalizers (ambulance grade hardware), 
off-the-shelf DC-to-DC converters (some only lasted 2 years) and custom 
DC-to-DC converters with MPPT. All work well when they are designed for the 
peak load and continuous load, have good heat dissipation and their 
parasitic load is included in the system's energy production.


Joel Davidson

- Original Message - 
From: "Rob Shappell" 

To: "'RE-wrenches'" 
Sent: Friday, September 02, 2011 6:53 AM
Subject: Re: [RE-wrenches] unique battery bank design question



As far as I know, The DC/DC and the Equalizers do basically the same thing
(step up or down). I recollect that the Equalizers are adjustable and can 
be

used as a load dump. Enermaxer comes to mind. It's been a long time...
but a refresher will be gladly accepted from those in the know.

Rob Shappell

-Original Message-
From: re-wrenches-boun...@lists.re-wrenches.org
[mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Jason
Szumlanski
Sent: Friday, September 02, 2011 9:42 AM
To: RE-wrenches
Subject: Re: [RE-wrenches] unique battery bank design question

Yeah, Rob, you and I have talked about this before regarding 12V required
for generator start/control with a 48V battery bank. In that case we did 
the

inefficient thing by charging the generator starting battery with a 12V
charger off the AC output of the inverter. A separate PV panel was the 
more

expensive option. I appreciate your input on this.

What can you tell us about battery equalizers as an alternative to DC-DC
converters??

Jason Szumlanski
Fafco Solar

-Original Message-
From: re-wrenches-boun...@lists.re-wrenches.org
[mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Rob 
Shappell

Sent: Friday, September 02, 2011 8:24 AM
To: 'RE-wrenches'
Subject: Re: [RE-wrenches] unique battery bank design question

I never, never recommend taps of any sort, but sometimes we have to 
satisfy

the needs of the customer. If any taps are done in any manner I would
recommend AT LEAST an annual reconfig of the taps.

To reduce and/or eliminate the imbalance of the 12 volt and 24 volt taps,
you could install a 12 volt charging source to the 12 volt tap, a 24 volt
charging source to the 24 volt tap and the 48 volt loads get a 48 volt
charging source. The array is still calculated the same, just distributed
different through different controllers. Is this bullet proof or perfect?
Nope, but neither are DC/DC converters and the system is much more 
efficient

too.

Rob Shappell



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[RE-wrenches] Warranty repair costs [was Evergreen goes down]

2011-08-19 Thread Joel Davidson
How much does a $29 part cost your business when you have to pay a technician 
to travel to a jobsite, troubleshoot, submit an RMA or order a replacement, and 
return and replace the bad unit? I advise contractors not to subsidize bad 
equipment suppliers by doing repairs and replacements at their own expense. I 
also advise suppliers to factor in realistic service costs and support their 
installing contractors.

Joel Davidson

  - Original Message - 
  From: Jason Szumlanski 
  To: RE-wrenches 
  Sent: Friday, August 19, 2011 3:47 AM
  Subject: Re: [RE-wrenches] Evergreen goes down


  Sounds like you are making a good argument for microinverters. We've already 
had that warranty discussion, but if module mismatch is an expensive and 
difficult to manage module warranty issue, microinverters allow you to, a) not 
replace a bad module, or b) replace it with a different module if physical size 
permits.

   

  All I am saying is that warranty becomes less of an issue as equipment prices 
drop. When my DVD player cost $500 I wanted a warranty. When it cost $29, not 
so much.

   

  Jason Szumlanski

  Fafco Solar

   

  From: re-wrenches-boun...@lists.re-wrenches.org 
[mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Joel Davidson
  Sent: Thursday, August 18, 2011 5:48 PM
  To: RE-wrenches
  Subject: Re: [RE-wrenches] Evergreen goes down

   

  Hello Jason,

   

  Warranty coverage could be a non-issue if you buy from a company with a 
warranty escrow account. Still, call-back costs and finding same-size, 
same-spec replacement modules costs do matter. Factor in travel time, labor, 
troubleshooting, finding replacement modules, paperwork, phone calls, etc. to 
replace 200-watt modules that cost less than $400? Not to mention how selling 
bad products and buying from unreliable suppliers affect your reputation. How 
many spare modules and inverters can a contractor afford to stock? The risk is 
always there because even reputable manufacturers make bad modules. The pile of 
bad modules made by reputable companies keeps growing. Europeans have recently 
recycled 600 tonnes of solar modules plus thousands of dead inverters. See 
  
http://www.waste-management-world.com/index/display/article-display/2373267650/articles/waste-management-world/opinion/2011/08/Solar_PV_Recycling_-_One_Step_Ahead_.html
 

   

  600 tonnes at 40 lbs/module = approx 33,000 modules at 150 watts = approx 5 
MW. 5 MW sounds like a lot but is only 0.03% of the 16 GW installed PV in 
Europe. Are wrenches seeing less than 0.03% of the modules they install ending 
up in the trash or sent back to the manufacturer?

   

  Yes, Astropower made a good module. Some good people use to work there.

   

  Joel Davidson

   

   

- Original Message - 

From: Jason Szumlanski 

To: RE-wrenches 

Sent: Thursday, August 18, 2011 12:10 PM

Subject: Re: [RE-wrenches] Evergreen goes down

 

Pretty soon I believe warranty coverage will become a virtual non-issue. At 
well under $2/watt, does it matter much anymore? Is there really that much risk 
of product or performance failure with most reputable manufacturers?

 

Yes, I paid $10+/w for Astropower modules over a decade ago, and warranty 
definitely mattered at that time.

 

Anyway. sad to see them go. We were a big fan for a while.

 

Jason Szumlanski

Fafco Solar 

 

 

From: re-wrenches-boun...@lists.re-wrenches.org 
[mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of boB Gudgel
Sent: Thursday, August 18, 2011 2:23 PM
To: RE-wrenches
Subject: Re: [RE-wrenches] Evergreen goes down

 

On 8/18/2011 11:10 AM, Marco Mangelsdorf wrote: 

Evergreen Solar, one of the last remaining independent U.S. module 
manufacturers, announced their plan to file for bankruptcy protection this week.

 

Done in by plummeting module pricing no doubt.

 

I'm sure you all are getting the same kind of solicitation emails that I 
get from mod manufacturers and wholesalers from across the globe peddling mods 
at low, low prices, including Evergreen.

 

Anyone have any idea what's going to happen to the warranty coverage for 
Evergreen mods?  Will they become unwanted, unwarrantied orphans, a la 
Astropower?

 

Sad, sad..

 

marco

 




I'd beware of newer companies offering say,   50 year warranties !

Hopefully NOT the new business model  !

boB








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Re: [RE-wrenches] Out of Warranty Inverter Replacements

2011-08-19 Thread Joel Davidson
Out of Warranty Inverter ReplacementsWhere inverters and other equipment are 
mounted affects their life. Exposure to south and west intense sun and heat and 
exposure to sea winds shorten equipment life even if the equipment is turned 
off.
  - Original Message - 
  From: Mark Frye 
  To: 'RE-wrenches' 
  Sent: Friday, August 19, 2011 10:56 AM
  Subject: Re: [RE-wrenches] Out of Warranty Inverter Replacements


  Ray,

  Here are the nameplate module rating vs nameplate inverter rating:

  - 24 x 175 W = 4,200 W : IG4000 = 4,000 W : 105 %
  - 18 x 175 W = 3,150 W : IG3000 = 2,700 W : 117 %
  - 8 x 175 W = 1,400 W : SB1100 = 1,100 W : 127 % (sub-optimal orientation 
limits peak power levels)

  I think it is fair to say that amps=heat=component aging. The question is to 
what extent can the installer rely on the representations made by manufactures 
with respect to their ratings and product life?

  For instance, the 24 module system above lands well within the Fronius 
specifications for max DC power and is "Good" based on their online 
configuration tool, and also well in line the the SMA white paper of many years 
ago suggesting a 120% mod/inv ratio as optimal.

  And yet, the first unit failed in 4 years and the refurb failed in 2 year.

  Mark Frye 
  Berkeley Solar Electric Systems 
  303 Redbud Way 
  Nevada City,  CA 95959 
  (530) 401-8024 
  www.berkeleysolar.com  




--
  From: re-wrenches-boun...@lists.re-wrenches.org 
[mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Ray Walters
  Sent: Friday, August 19, 2011 10:26 AM
  To: RE-wrenches
  Subject: Re: [RE-wrenches] Out of Warranty Inverter Replacements


  Hi Mark;

  In cases like that, I let the customer decide. My job is to present them with 
two or three streamlined options and let them decide.
  It seems it comes down to cost vs continued warranty (and possible 
expandability?). Financial decisions ultimately need to be made by the people 
paying the bill.
  From a technical perspective, I don't ever present an option that I wouldn't 
be comfortable installing, and in the end everyone's happy. (hopefully)

  Just curious; what are the array sizes relative to the inverter rating? I 
always wondered if inverters that were run at or over their rating didn't last 
as long as inverters that were run well below their rating. (just my stupid 
assumption that: more amps = more heat = less reliability)

  Ray


  On 8/19/2011 11:03 AM, Mark Frye wrote: 
Folks, 

Yesterday I took a trip through my service area and initated 3 inverter 
replacement actions: 

- A 6 year old Sunnyboy 1100W, 5 year warranty expired, $360 for a 
refurbished unit w/ 1 year warranty, new replacement not available

- A 2 year old Fronius IG4000 refurbished, sent as warranty replacement for 
unit failed at 4 years under 5 year warranty, now out of warranty, est. $ 600 
to refurbish with 1 year warranty

- A 4 year old Fronius IG3000, under 10 year warranty, warranty replacement 
and service fee provided by Fronius 

I have to decide, what is best for my out of warranty customers: 

- Buy the refurbished units w/ 1 year warranty 
- Buy new replacement units with 10 or 20 year warrranties 
- Buy entirely new equipment such as Enphase or SolarEdge 

What are other folks experiencing as we move well past the 5 year warranty 
horizon for many of our earlier customers? 

Mark Frye 
Berkeley Solar Electric Systems 
303 Redbud Way 
Nevada City,  CA 95959 
(530) 401-8024 
www.berkeleysolar.com  


 

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Re: [RE-wrenches] Evergreen goes down

2011-08-18 Thread Joel Davidson
Hello Jason,

Warranty coverage could be a non-issue if you buy from a company with a 
warranty escrow account. Still, call-back costs and finding same-size, 
same-spec replacement modules costs do matter. Factor in travel time, labor, 
troubleshooting, finding replacement modules, paperwork, phone calls, etc. to 
replace 200-watt modules that cost less than $400? Not to mention how selling 
bad products and buying from unreliable suppliers affect your reputation. How 
many spare modules and inverters can a contractor afford to stock? The risk is 
always there because even reputable manufacturers make bad modules. The pile of 
bad modules made by reputable companies keeps growing. Europeans have recently 
recycled 600 tonnes of solar modules plus thousands of dead inverters. See 
http://www.waste-management-world.com/index/display/article-display/2373267650/articles/waste-management-world/opinion/2011/08/Solar_PV_Recycling_-_One_Step_Ahead_.html
 

600 tonnes at 40 lbs/module = approx 33,000 modules at 150 watts = approx 5 MW. 
5 MW sounds like a lot but is only 0.03% of the 16 GW installed PV in Europe. 
Are wrenches seeing less than 0.03% of the modules they install ending up in 
the trash or sent back to the manufacturer?

Yes, Astropower made a good module. Some good people use to work there.

Joel Davidson



  - Original Message - 
  From: Jason Szumlanski 
  To: RE-wrenches 
  Sent: Thursday, August 18, 2011 12:10 PM
  Subject: Re: [RE-wrenches] Evergreen goes down


  Pretty soon I believe warranty coverage will become a virtual non-issue. At 
well under $2/watt, does it matter much anymore? Is there really that much risk 
of product or performance failure with most reputable manufacturers?

   

  Yes, I paid $10+/w for Astropower modules over a decade ago, and warranty 
definitely mattered at that time.

   

  Anyway. sad to see them go. We were a big fan for a while.

   

  Jason Szumlanski

  Fafco Solar 

   

   

  From: re-wrenches-boun...@lists.re-wrenches.org 
[mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of boB Gudgel
  Sent: Thursday, August 18, 2011 2:23 PM
  To: RE-wrenches
  Subject: Re: [RE-wrenches] Evergreen goes down

   

  On 8/18/2011 11:10 AM, Marco Mangelsdorf wrote: 

  Evergreen Solar, one of the last remaining independent U.S. module 
manufacturers, announced their plan to file for bankruptcy protection this week.

   

  Done in by plummeting module pricing no doubt.

   

  I'm sure you all are getting the same kind of solicitation emails that I get 
from mod manufacturers and wholesalers from across the globe peddling mods at 
low, low prices, including Evergreen.

   

  Anyone have any idea what's going to happen to the warranty coverage for 
Evergreen mods?  Will they become unwanted, unwarrantied orphans, a la 
Astropower?

   

  Sad, sad..

   

  marco

   




  I'd beware of newer companies offering say,   50 year warranties !

  Hopefully NOT the new business model  !

  boB








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Re: [RE-wrenches] mechanical vs. electronic kwh meter

2011-08-12 Thread Joel Davidson
Electronic meters always work in favor of the utility company. Mechanical 
meters can be ratcheted 1-way or unratcheted bi-directional. Bi-directional 
meters can be calibrated accurately. Meters are the utility's cash registers. 
Businesses get very angry if you touch or even look closely at their cash 
registers. The recession has resulted in more business closings and home 
foreclosures which means fewer utility meters and less revenue so utility 
companies are watching their meters very closely. Utility workers are also 
concerned about bi-directional electricity flow safety. LADWP's revised solar 
program says if the PV system meter shows 10 hours or more PV production before 
the net-meter is placed, then the customer forfeits the rebate and the 
contractor can be taken off the approved installers list. It often takes 
Southern California Edison 6 to 8 weeks place a meter on a PV system. LADWP is 
even slower. Yet new non-PV services get meters/cash registers placed usually 
within 3 days. Expect strong pushback if you try to fight your electric 
utility's meter policy. You're better off making friends so that they place 
meters on your jobs quickly.

Joel Davidson

  - Original Message - 
  From: Kirk Herander 
  To: RE-wrenches 
  Sent: Friday, August 12, 2011 6:45 AM
  Subject: [RE-wrenches] mechanical vs. electronic kwh meter


  Hello,

   

  I am now in a debate with the metering dept. of a local utility. They don't 
want a PV system to be energized and tested until a bidirectional electronic 
meter is installed. They insist that an old plain Jane mechanical meter can be 
damaged and is a safety concern if power is pushed through it (its running 
backwards) to the grid. I have never heard of, witnessed, or been told this by 
any utility or AHJ inspector until now. Have any of you ever?

   

  I don't know the reason for their paranoia. I assume that many utility 
districts don't to this day install bidirectional electronic meters. And rely 
on the original mechanical meter to count backwards reliably and safely.  

   

  Kirk Herander

  VT Solar, LLC

  dba Vermont Solar Engineering

  NABCEPTM Certified installer Charter Member

  NYSERDA-eligible Installer

  VT RE Incentive Program Partner

   



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Re: [RE-wrenches] Power Factor (was Efficient step up, down transformers)

2011-07-26 Thread Joel Davidson

Hi Bob,
The inverter PF was 1.0. The grid was always less than 1.0 and often down to 
0.7. LADWP would not say what they did to fix the problem.

Joel Davidson

- Original Message - 
From: "boB Gudgel" 

To: "RE-wrenches" 
Cc: "Joel Davidson" 
Sent: Tuesday, July 26, 2011 7:30 PM
Subject: Re: [RE-wrenches] Power Factor (was Efficient step up, down 
transformers)




On 7/26/2011 4:42 PM, Joel Davidson wrote:
Power factor less than 1.0 can shorten the life of and damage equipment 
and reduce PV production. We installed a 200 kW PV system on a facility 
with a lot of 3-phase motors and monitored the PV and the grid. We 
measured around 0.7 PF being delivered by the Los Angeles Dept of Water & 
Power. The data was used as evidence by the PV client to negotiate 
compensation for lost power and get better quality power at that site and 
other facilities. Now I always monitor utility power on commercial 
systems for trouble-shooting.


Joel Davidson




That's very interesting...   I would expect   a current-source type grid 
tie inverter would
be very close to PF of 1.0 (if that one WAS a CS type which I would think 
it would be)


Might be because the grid voltage at that facility is really distorted 
because of the loads
you mentioned.  Did you measure the PF of the line from the GT inverter 
itself ?


What kind of inverter system was this ??   A big one of course.

Some GT inverters that are more of a voltage source will supply lower 
power factor

and tend to clean up the dirty voltage waveform.

boB







- Original Message - From: "Exeltech" 
To: "RE-wrenches" 
Sent: Tuesday, July 26, 2011 12:13 PM
Subject: Re: [RE-wrenches] Efficient step up, down transformers


Hello Ray,

Wow.  I could do an another thesis on the topic of
power factor alone...

There's no good way to fully explain this in depth
here .. so all we can do is scratch the surface.


First, a quick review.

Power factor less than 1.0 causes current flow in a load
that's out of phase with the applied voltage.  The actual
power delivered to the load (and thus consumed by the
source, disregarding efficiency for now), would be:
Vac * Iac * COS(theta) .. where theta is the phase angle
differential between the voltage and current (with the
values for V and I in rms).

Though the real power consumed in a reactive circuit
is going to be less than the real power consumed in
an equivalent resistive circuit (by virtue of the
phase angle), the amperage in the reactive circuit
is still whatever is flowing.

Now, to answer your question...

All inverters will operate at a lower efficiency
when connected to a load with lousy power factor
than if connected to a purely resistive load
under similar operating conditions (VA vs. watts).

The actual efficiency reduction will depend also
on whether the low power factor is due to reactive
components (e.g. inductors or capacitors), or
due to a non-linear load, such as a switching power
supply in a computer, microwave oven, etc.

Nonlinear loads present their own issues that I'll
skip for now.  Let's presume reactive...


That said...

The majority of the losses in inverters under
these conditions would be resistive.


Here's why:
Inverters made with power transformers have large
amounts of copper wire, and consequently, wire
resistance.  When connected to a load with a poor
power factor, transformer-based inverters will not
perform as efficiently as they do when connected
to a purely resistive load.

With a very low power-factor load, you could
theoretically be providing the max current from
an inverter at much lower real power output than
it's rated.  This additional loss, when taken
into account at an AC power with low real wattage
output, will make the inverter's efficiency
worse than with a resistive load.  Expect the
efficiency hit to be on the order of 2-5% for
transformer-based inverters (again, depending on
inverter's max wattage rating as well, as this
will impact the wire size used in its construction,
and thus the total wire resistance).

Transformerless inverters don't have this large
mass of wire (thus much lower internal resistance).
Subsequently, they aren't nearly as affected by
low-power-factor loads - but even here, I'd expect
around 0.5-1% efficiency reduction, all other
conditions being equal.


Power factor is deceptively simple .. but is one of
the more complex aspects of power systems and
power equipment design.


Hope this helps.


Dan Lepinski
Sr. Engineer
Exeltech


P.S. Thanks for being a long-time Exeltech customer.
Much appreciated.



--- On Mon, 7/25/11, R Ray Walters  wrote:

From: R Ray Walters 
Subject: Re: [RE-wrenches] Efficient step up, down transformers
To: "RE-wrenches" 
Date: Monday, July 25, 2011, 4:10 PM
Hi Dan;

I agree that a 2000 VA inverter isn't equal to a 2000 watt
unit.

The focus on VA here though was not about looking 

[RE-wrenches] Power Factor (was Efficient step up, down transformers)

2011-07-26 Thread Joel Davidson
Power factor less than 1.0 can shorten the life of and damage equipment and 
reduce PV production. We installed a 200 kW PV system on a facility with a 
lot of 3-phase motors and monitored the PV and the grid. We measured around 
0.7 PF being delivered by the Los Angeles Dept of Water & Power. The data 
was used as evidence by the PV client to negotiate compensation for lost 
power and get better quality power at that site and other facilities. Now I 
always monitor utility power on commercial systems for trouble-shooting.


Joel Davidson

- Original Message - 
From: "Exeltech" 

To: "RE-wrenches" 
Sent: Tuesday, July 26, 2011 12:13 PM
Subject: Re: [RE-wrenches] Efficient step up, down transformers


Hello Ray,

Wow.  I could do an another thesis on the topic of
power factor alone...

There's no good way to fully explain this in depth
here .. so all we can do is scratch the surface.


First, a quick review.

Power factor less than 1.0 causes current flow in a load
that's out of phase with the applied voltage.  The actual
power delivered to the load (and thus consumed by the
source, disregarding efficiency for now), would be:
Vac * Iac * COS(theta) .. where theta is the phase angle
differential between the voltage and current (with the
values for V and I in rms).

Though the real power consumed in a reactive circuit
is going to be less than the real power consumed in
an equivalent resistive circuit (by virtue of the
phase angle), the amperage in the reactive circuit
is still whatever is flowing.

Now, to answer your question...

All inverters will operate at a lower efficiency
when connected to a load with lousy power factor
than if connected to a purely resistive load
under similar operating conditions (VA vs. watts).

The actual efficiency reduction will depend also
on whether the low power factor is due to reactive
components (e.g. inductors or capacitors), or
due to a non-linear load, such as a switching power
supply in a computer, microwave oven, etc.

Nonlinear loads present their own issues that I'll
skip for now.  Let's presume reactive...


That said...

The majority of the losses in inverters under
these conditions would be resistive.


Here's why:
Inverters made with power transformers have large
amounts of copper wire, and consequently, wire
resistance.  When connected to a load with a poor
power factor, transformer-based inverters will not
perform as efficiently as they do when connected
to a purely resistive load.

With a very low power-factor load, you could
theoretically be providing the max current from
an inverter at much lower real power output than
it's rated.  This additional loss, when taken
into account at an AC power with low real wattage
output, will make the inverter's efficiency
worse than with a resistive load.  Expect the
efficiency hit to be on the order of 2-5% for
transformer-based inverters (again, depending on
inverter's max wattage rating as well, as this
will impact the wire size used in its construction,
and thus the total wire resistance).

Transformerless inverters don't have this large
mass of wire (thus much lower internal resistance).
Subsequently, they aren't nearly as affected by
low-power-factor loads - but even here, I'd expect
around 0.5-1% efficiency reduction, all other
conditions being equal.


Power factor is deceptively simple .. but is one of
the more complex aspects of power systems and
power equipment design.


Hope this helps.


Dan Lepinski
Sr. Engineer
Exeltech


P.S. Thanks for being a long-time Exeltech customer.
Much appreciated.



--- On Mon, 7/25/11, R Ray Walters  wrote:

From: R Ray Walters 
Subject: Re: [RE-wrenches] Efficient step up, down transformers
To: "RE-wrenches" 
Date: Monday, July 25, 2011, 4:10 PM
Hi Dan;

I agree that a 2000 VA inverter isn't equal to a 2000 watt
unit.

The focus on VA here though was not about looking at the
rating of the inverter, but instead noting that a load with
a high reactive component might draw more energy than a
purely resistive load in a battery based inverter system. AC
watts might be equal, but my understanding (perhaps false?)
is that the inverter efficiency decreases with PF.

SInce you're in the inverter manufacturing biz, perhaps you
could better explain this to the rest of us.

My fundamental question is: how does power factor effect
the efficiency of an inverter?

A better understanding of this issue would not only help us
with the current issue of transformers vs. big wire,
but also help us better size battery based systems to all
types of AC loads.

Thanks in advance for your time,

R. Walters
r...@solarray.com
Solar Engineer
(and long time Exeltech user)



On Jul 25, 2011, at 1:41 PM, Exeltech wrote:

> Focusing on VA ratings would not be advisable.
>
> Here's why.
>
> Watts are real power. This would be actual DC
> volts times actual DC amps. Measuring DC volt

Re: [RE-wrenches] Fwd: Car charging station without grid

2011-07-14 Thread Joel Davidson
Allan,

We also did what Dana suggests (as did many PV and or EV wrenches). For us, the 
idea morphed into www.solarelectricalvehicles.com Whether PV is on the vehicle 
or somewhere else, tapping into the vehicle battery bank voids the vehicle 
warranty.

Joel Davidson

  - Original Message - 
  From: Dana 
  To: al...@positiveenergysolar.com ; 'RE-wrenches' 
  Sent: Thursday, July 14, 2011 3:32 PM
  Subject: Re: [RE-wrenches] Fwd: Car charging station without grid


  Hey Allan,

   

  We did freestanding  golf cart charger direct dc array to charger controller 
with a direct coupler to the golf cart's battery. Works just like an off grid 
system.

   

  Could you do the same for a car? Bypassing or paralleling the internal 
controls.

   

  Dana Orzel

  Great Solar Works, Inc

  E - d...@solarwork.com

  V - 970.626.5253

  F - 970.626.4140

  C - 970.209.4076

  web - www.solarwork.com

   

  "Responsible Technologies for Responsible People since 1988"

  Do not ever believe anything, but seriously trust through action.

   

  From: re-wrenches-boun...@lists.re-wrenches.org 
[mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Allan Sindelar
  Sent: Thursday, July 14, 2011 2:43 PM
  To: RE-wrenches
  Subject: [RE-wrenches] Fwd: Car charging station without grid

   

  Wrenches,
  I'm stumped as to the best approach for a customer who wants a non-grid-tied, 
batteryless PV-powered EV charging station. See below, from one of our 
salespeople. Any ideas?
  Thank you, 
  Allan




   



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Re: [RE-wrenches] Fwd: Car charging station without grid

2011-07-14 Thread Joel Davidson
Hi Allan,

Off-grid batteryless EV charging? Perhaps if the EV battery was tapped to keep 
the off-grid inverter awake, but that would void the vehicle warranty. I'm sure 
you considered PV into Sunny Islands (or similar) with a small sealed battery 
into Sunny Boys. I question if a person in SF who wants an off-grid PV system 
without batteries to charge a battery vehicle is really a customer.

Good luck,
Joel Davidson
  - Original Message - 
  From: Allan Sindelar 
  To: RE-wrenches 
  Sent: Thursday, July 14, 2011 1:43 PM
  Subject: [RE-wrenches] Fwd: Car charging station without grid


  Wrenches,
  I'm stumped as to the best approach for a customer who wants a non-grid-tied, 
batteryless PV-powered EV charging station. See below, from one of our 
salespeople. Any ideas?
  Thank you, 
  Allan

   Original Message 

  Allan:
  Monday I sit down with an interesting fellow who sounds like a potential good 
customer (has money and right enviro goals) - in SF.
  He brought up the idea of discussing a car charging station for future 
electric car that:

1.. stands alone, no grid connection 
2.. no batteries - he pictures his car is home most days - he parks it and 
when the sun shines it gets charged directly 
  Why that approach?

1.. He is thinking this must be the most efficient conversion, i.e. 
directly without batteries or line loss of electrons to and from utility 
2.. Wants the car to function independent of dirty fuel/dirty electrons 
3.. He assumes less equipment; maybe less cost but the cost is not 
important other than as example for others 
  Issues I see:

1.. All inverters that can produce the high voltage needed need grid power 
or if off grid need batteries - know of anything stand alone available? 
2.. Power or voltage fluctuation as panels see more or less sun; ie hours 
of day or clouds, etc - what will be the output from inverter? 
3.. Without tieing into grid investment in PVs (both his financial and the 
embodied for manuf.) gets wasted when car fully charged or car not home and 
sunny. 
4.. Is total amps output in peak sun even going to meet the charging 
requirements? ie takes 10 days to recharge instead of 4 hours - or overly 
massive system to match rate of charge? 
  Your thoughts?
  Karlis


  Allan Sindelar
  al...@positiveenergysolar.com
  NABCEP Certified Photovoltaic Installer
  NABCEP Certified Technical Sales Professional
  New Mexico EE98J Journeyman Electrician
  Positive Energy, Inc.
  3201 Calle Marie
  Santa Fe, New Mexico 87507
  505 424-1112
  www.positiveenergysolar.com 


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Re: [RE-wrenches] Dangerous installs/installers..

2011-07-01 Thread Joel Davidson
Wrenches,
We've seen solar shutters displayed recently at two trade shows in the Los 
Angeles area. See http://plugnsaveenergyproducts.com/shutters/ The solar 
shutters use zip cord and the people at the shows were telling people to just 
plug the inverter into a wall outlet. I told them that they were violating the 
NEC and endangering people. They replied that ETL is testing their product and 
said it will get listed and be put on the CEC eligible module list. We asked 
how much power a solar shutter produces when mounted inside a window and 
getting light through the window and frame and if one shutter slat shades cells 
on the slat below it. They replied that their solar shutter works and seem to 
sincerely believe in their product.
Joel Davidson
  - Original Message - 
  From: R Ray Walters 
  To: RE-wrenches 
  Sent: Saturday, May 07, 2011 12:34 PM
  Subject: Re: [RE-wrenches] Dangerous installs/installers..


  Even a bad solar installer isn't going to use cut up extension cords; that 
install was DIY or a "knowledgable" inebriated neighbor. I lived in the 
backwoods for many years, and saw even my own work get turned into horror 
systems. 
  As far as your competitor doing bad work, we had the same problem for years 
with a guy who was finally run out of Taos by the inspector and a growing list 
of angry customers.
  He's now in California doing Wholesale Solar.
  Your best bet is to turn him in to the AHJ for illegal contracting, along 
with pics of the work., but make dang sure he really did it. Enough complaints 
and eventually they'll get him.
  Luckily much of the system can survive without OCP; the array is current 
limited and won't pop an OCP anyway, and the house wiring can't actually fry at 
2500 watts continuous, so a battery wiring issue will be the most dangerous 
situation. (batteries on NEC systems are not really protected from the most 
likely dangers like a wrench being dropped across the terminals)


  I've rewire dozens of such monsters, and you don't even want to have your 
fingerprints on it without having approval to completely rewire it.
  Also, for budget cabin systems  like that, we would often just supply parts 
and a wiring diagram, and let them keep the liability. 
  It can get cost prohibitive and unnecessary to bring the whole system up to 
NEC 2011, my own beautiful house has 103 yr old Knob & tube wiring that is 
going great. I only added AFCI breakers and replaced all the lights with low 
current CFs. 
  You have to suspend some of the code junky in you, and proceed with common 
sense, or don't proceed at all.
  Definitely not for the faint of heart, Good luck,


  R. Walters
  r...@solarray.com
  Solar Engineer








  On May 7, 2011, at 11:21 AM, Jesse Dahl wrote:


Good point, and I guess I could see work like this from a homeowner, but 
this is from a "energy solutions" company in my area. I can fix the problems 
with the solar, some new parts, some conduit, pull some wire.. 
I just don't know what to do about this "energy solutions" guy. Show him 
why it's wrong, confront him 


Thanks,




Jesse

Sent from my iPhone

On May 7, 2011, at 11:37 AM, "Jason Szumlanski"  
wrote:


  Yeah – it can be scary. Retrofits/fix-its are the worst, but can be fun 
and profitable at times. Starting from scratch is usually the answer, reusing 
components if practical.


  Word of caution… be careful not to harshly criticize work in front of the 
customer. Sometimes they claim that “another idiot PV installer” did the 
system, when in fact it was a DIY installation. You can be matter of fact about 
the safety hazards and code violations, but I’ve seen the look on a person’s 
face who obviously did it himself as I tore the system apart. 


  Jason Szumlanski

  Fafco Solar 



  From: re-wrenches-boun...@lists.re-wrenches.org 
[mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of 
d...@foxfire-energy.com
  Sent: Saturday, May 07, 2011 7:58 AM
  To: RE-wrenches
  Subject: Re: [RE-wrenches] Dangerous installs/installers..


  Welcome to the Rodeo partner.. 



  Dan Brown
  Foxfire Energy Corp.
  Renewable Energy Systems
  (802)-483-2564
  www.Foxfire-Energy.com
  NABCEP #092907-44


 Original Message 
Subject: [RE-wrenches] Dangerous installs/installers..
From: Jesse Dahl 
Date: Sat, May 07, 2011 2:45 am
To: RE-wrenches 

Wrenches,

 The other day on my travels, I came across a very scary small 
stand-alone hunting shack install.  All the wiring is cut extension cords and 
some UF, the cable from the charge controller to the batteries is an extension 
cord with the 14s paralleled.   mice chewed wire, splices taped and laid on the 
ground, mis matched modules (least of the problems). not a disco or OCPD to 

Re: [RE-wrenches] commercial system monitoring

2011-06-09 Thread Joel Davidson
Daron Stein
Locus Energy LLC
646 395 9913(desk)
646 660 5223 (cell)
www.locusenergy.com


  - Original Message - 
  From: Marco Mangelsdorf 
  To: 'RE-wrenches' 
  Sent: Thursday, June 09, 2011 11:52 AM
  Subject: [RE-wrenches] commercial system monitoring


  I'm looking for a bare-bones, cheap (hah!) web-based monitoring system for 
three-phase systems using either Satcon or PV Powered inverters.

   

  I'm having a hard time finding any package (it doesn't have to be bloomin' 
"revenue-grade") under $3,000.

   

  Anyone know of anything reputable and lower cost out there?

   

  Thanks,

  marco

   



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Re: [RE-wrenches] Los Angeles Assessor Form

2011-05-19 Thread Joel Davidson

Peter,

The PV system is property tax exempt. Do not fill out the form. Instead, the 
property owner has to contact the tax assessor's office and fill out this 
form: http://www.boe.ca.gov/proptaxes/pdf/lta08071.pdf


Joel Davidson

- Original Message - 
From: "Peter Parrish" 

To: "'RE-wrenches'" 
Sent: Thursday, May 19, 2011 9:35 AM
Subject: [RE-wrenches] Los Angeles Assessor Form


Has anyone had to help a client (Los Angeles County, California) filling 
out
a "Property Owner's Statement - New Construction". This form was sent to 
the

client/homeowner, apparently triggered by the issuance of a permit to
install a PV system.

I gave it a quick once over and there does not appear to be a place for
exempt projects such as wind and solar.

Any help from someone who has actually filled out one of these forms, 
would

be much appreciated.

- Peter


Peter T. Parrish, Ph.D., President
California Solar Engineering, Inc.
820 Cynthia Ave., Los Angeles, CA 90065
CA Lic. 854779, NABCEP Cert. 031806-26
peter.parr...@calsolareng.com
Ph 323-258-8883, Mobile 323-839-6108, Fax 323-258-8885



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Re: [RE-wrenches] Side-by-side microinverter, maximizer, and conventional inverter comparisons

2011-05-09 Thread Joel Davidson

Hello Bill,

Henk Oldenkamp is the inventor of the OK4U microinverter. Perhaps David Katz 
knows what Henk is up to lately. The OK4U inverter that I first tested on 
the Solec International factory roof in 1994 worked ok (as specified).


The central inverters vs. multiple small inverters side-by-side comparison 
was also in Los Angeles on a 400 kW PV array between 2 each Xantrex 100 kW 
central inverters and 74 each SMA 2500 inverters (both circa 2003). The kW 
and kWh output was the same for both configurations.


Joel Davidson

- Original Message - 
From: "Bill Loesch" 

To: "RE-wrenches" 
Sent: Monday, May 09, 2011 7:10 AM
Subject: Re: [RE-wrenches] Side-by-side microinverter, maximizer,and 
conventional inverter comparisons





Joel,

As I remember Trace rebranded the (nominal 100 watt) OK4U units as 
MicroSine

about 2000 AD. Didn't SMA (or someone else) recently take over the OK4U
product line?

Do I understand you were not impressed with the MPPT OK4U microinverters
performance (vs. the non-MPPT SMA?) under full sun?

Do I understand correctly that you compared some 2,000 (OK4U?) 
microinverter

units
with 74 transformerless (?) SMA machines?

The "as much as", "up to", etc. wording is why "caveat emptor" and "Your
Mileage May Vary" should accompany each one of those comments. Kudos
marketing mavens.

Bill Loesch
Solar 1 - Saint Louis Solar
314 631 1094



- Original Message - 
From: "Joel Davidson" 

To: "RE-wrenches" 
Sent: Wednesday, May 04, 2011 8:54 AM
Subject: [RE-wrenches] Side-by-side microinverter, maximizer,and
conventional inverter comparisons



Wrenches,

A few years ago, we compared conventional and MPPT charge controllers and
found power production improvement in only in unique conditions and 
rarely

over 15%. Now Microinverter and DC maximizer companies are claiming "as

much

as 25%" increased electricity production and a booming market. See


http://www.interpv.net/market/market_view.asp?idx=401&code=401&part_code=01


I've been comparing grid-connected microinverters since 1994 when Henk

came
out with his OK4U and am not impressed in full-sun (no shade) 
comparisons.

In 2005, I compared a side-by-side 200 kW system with two 100 kW Xantrex
inverters with a 200 kW system with 74 SMA inverters and saw no 
difference

in kW or kWh.

Have any wrenches made side-by-side comparisons? Are the claimed
improvements hype or real?

Joel Davidson

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Re: [RE-wrenches] Dangerous installs/installers..

2011-05-07 Thread Joel Davidson
Except for the renewable energy equipment, I saw poor wiring throughout India, 
soon to be the most populated country in the world. As my Arkansas Ozark 
mountain neighbor with poor wiring use to say about poverty of the mind, "Poor 
folks have poor ways." I hope you left a wiring diagram of a properly designed 
system.

Joel Davidson

  - Original Message - 
  From: Jesse Dahl 
  To: RE-wrenches 
  Sent: Friday, May 06, 2011 11:45 PM
  Subject: [RE-wrenches] Dangerous installs/installers..


  Wrenches,

   The other day on my travels, I came across a very scary small stand-alone 
hunting shack install.  All the wiring is cut extension cords and some UF, the 
cable from the charge controller to the batteries is an extension cord with the 
14s paralleled.   mice chewed wire, splices taped and laid on the ground, mis 
matched modules (least of the problems). not a disco or OCPD to be seen. 

  Also a 500W wind generator 100 yards from the battery bank, feed with #10s 
and then spliced to #12s (most of it just laying on the ground.  

  Now I think the owner should have some responsibility to stop work when the 
see things this awful, but what can/should we as an industry do about this? 
What do we say to people that install stuff like this? Take them to court?

  A small 2500w with surge of 5000w inverter was used here with 6 paralleled 
12V deep cycle batteries. Powering a few lights and a vacuum at first, a well 
pump was added later. I could see the lights and vacuum, but a pump?  How do 
you go about wiring the output of an inverter like this?  From a receptacle on 
the inverter to what? This guy cut an extension cord off and splice it to some 
NM and ran it inside to the loads. No breaker, I just can't get over the fact 
this guy sleeps at night...




  You should see the photos of this mess...


  Thank you for your thoughts,



  Jesse

  Sent from my iPhone


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[RE-wrenches] Side-by-side microinverter, maximizer, and conventional inverter comparisons

2011-05-04 Thread Joel Davidson

Wrenches,

A few years ago, we compared conventional and MPPT charge controllers and 
found power production improvement in only in unique conditions and rarely 
over 15%. Now Microinverter and DC maximizer companies are claiming "as much 
as 25%" increased electricity production and a booming market. See 
http://www.interpv.net/market/market_view.asp?idx=401&code=401&part_code=01


I've been comparing grid-connected microinverters since 1994 when Henk came 
out with his OK4U and am not impressed in full-sun (no shade) comparisons. 
In 2005, I compared a side-by-side 200 kW system with two 100 kW Xantrex 
inverters with a 200 kW system with 74 SMA inverters and saw no difference 
in kW or kWh.


Have any wrenches made side-by-side comparisons? Are the claimed 
improvements hype or real?


Joel Davidson 


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[RE-wrenches] Battery SG testing (was Battery watering)

2011-04-03 Thread Joel Davidson
Hello Dana,

Sounds like you've solved the sore back problem without over- or under-watering 
cells.

I water and check electrolyte level every 2 to 6 months depending on the 
battery bank's age and use (grid-tie float only, off-grid daily 
charge/discharge, etc.). I encourage spot-checking specific gravity of about 
10% of the cells before each scheduled watering and changing the sampling cells 
each time. That's only 5 cells of a 48 cell battery. But is that an adequate 
sampling or am I just rationalizing to avoid a sore back?

Joel Davidson
  - Original Message - 
  From: Dana 
  To: 'RE-wrenches' 
  Sent: Saturday, April 02, 2011 1:06 PM
  Subject: Re: [RE-wrenches] Battery watering


  Hey Joel,

  We have a couple of auto water systems in use that we connect manually and it 
takes less than 5 minutes to water a triple HUP 1690 amp hour-24vdc bank. 
Pretty sweet but doing the SG is a bit of a hassle as you have to unscrew each 
cap. I hear that there are auto water caps that have a port for the extraction 
of electrolyte for testing, but I have not used or seen this cap.

   

  Dana Orzel

  Great Solar Works, Inc

  E - d...@solarwork.com

  V - 970.626.5253

  F - 970.626.4140

  C - 970.209.4076

  web - www.solarwork.com

   

  "Responsible Technologies for Responsible People since 1988"

  Do not ever believe anything, but seriously trust through action.

   

  From: re-wrenches-boun...@lists.re-wrenches.org 
[mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Joel Davidson
  Sent: Saturday, April 02, 2011 9:59 AM
  To: RE-wrenches
  Subject: Re: [RE-wrenches] Battery watering

   

  Dana,

   

  One of my battery suppliers gave me the same or similar float. He said 
something like, "Here's a sample from one of the watering systems that we sell. 
It's pretty good, but sometimes the float sticks open and sometimes it sticks 
closed so I wouldn't turn on the water supply unless I was there to monitor 
it." He said that his forklift customers schedule 30 minutes for watering - 
turns the water on before going to lunch and checks to see if the cells are 
full when he comes back from lunch.

   

  Joel Davidson

- Original Message - 

From: Dana 

To: 'RE-wrenches' 

Sent: Friday, April 01, 2011 2:37 PM

Subject: [RE-wrenches] Battery watering

 

I found Battery Watering Systems ; http://www.batterywatering.com/

Kits and lots of options on parts for battery service.

I am getting a new pressure sprayer and ordered a "gun" that stops when the 
battery fluid is at a preset level $80, includes a flow meter visual, 20PSI 
pressure reducer, sprayer handle and auto stop tip.

No more sore back from leaning over the battery bank, Yes!

 

Dana Orzel

Great Solar Works, Inc

E - d...@solarwork.com

V - 970.626.5253

F - 970.626.4140

C - 970.209.4076

web - www.solarwork.com

 

"Responsible Technologies for Responsible People since 1988"

Do not ever believe anything, but seriously trust through action.

 




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Re: [RE-wrenches] Battery watering

2011-04-02 Thread Joel Davidson
Dana,

One of my battery suppliers gave me the same or similar float. He said 
something like, "Here's a sample from one of the watering systems that we sell. 
It's pretty good, but sometimes the float sticks open and sometimes it sticks 
closed so I wouldn't turn on the water supply unless I was there to monitor 
it." He said that his forklift customers schedule 30 minutes for watering - 
turns the water on before going to lunch and checks to see if the cells are 
full when he comes back from lunch.

Joel Davidson
  - Original Message - 
  From: Dana 
  To: 'RE-wrenches' 
  Sent: Friday, April 01, 2011 2:37 PM
  Subject: [RE-wrenches] Battery watering


  I found Battery Watering Systems ; http://www.batterywatering.com/

  Kits and lots of options on parts for battery service.

  I am getting a new pressure sprayer and ordered a "gun" that stops when the 
battery fluid is at a preset level $80, includes a flow meter visual, 20PSI 
pressure reducer, sprayer handle and auto stop tip.

  No more sore back from leaning over the battery bank, Yes!

   

  Dana Orzel

  Great Solar Works, Inc

  E - d...@solarwork.com

  V - 970.626.5253

  F - 970.626.4140

  C - 970.209.4076

  web - www.solarwork.com

   

  "Responsible Technologies for Responsible People since 1988"

  Do not ever believe anything, but seriously trust through action.

   



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Re: [RE-wrenches] Battery watering equipment

2011-04-01 Thread Joel Davidson
Forklift battery suppliers and Wrenches told me that automatic watering systems 
either stick closed (dry cells) or stick opened (flooded battery box). 
Warehouse operators told me that they operate their so-called automatic 
watering systems manually.

I use an RL Flo-Master 1.5-Gallon Polyethylene-Tank Sprayer from Home Depot for 
$11. It works great. 
Model # 1415D. Internet # 100637818. Store SKU # 367767

Joel Davidson
  - Original Message - 
  From: d...@foxfire-energy.com 
  To: RE-wrenches 
  Sent: Thursday, March 31, 2011 6:22 PM
  Subject: Re: [RE-wrenches] Battery watering equipment


  I like using a plant sprayer (a new one), with the end of the wand removed, 
and a piece of tape for a depth gauge.. and a good head light.. db




  Dan Brown
  Foxfire Energy Corp.
  Renewable Energy Systems
  (802)-483-2564
  www.Foxfire-Energy.com
  NABCEP #092907-44



 Original Message 
Subject: Re: [RE-wrenches] Battery watering equipment
From: jay peltz 
Date: Thu, March 31, 2011 7:14 pm
To: RE-wrenches 

Are you talking semi-automatic or manual?


jay


peltz power

On Mar 31, 2011, at 6:01 AM, Dana wrote:


  I am currently looking for recommendations on battery watering equipment. 
We have a regular route of clients that  want us to perform regular battery 
checks for SG and VPC and water afterwards, generator oil check and operation, 
control settings [older Trace and Xantrex equip. w/o non-volatile memories] etc.

  What has worked for you, who supplies it, would you buy it again?
  What would you do differently?

  Dana Orzel
  Great Solar Works, Inc
  E - d...@solarwork.com
  V - 970.626.5253
  F - 970.626.4140
  C - 970.209.4076
  web - www.solarwork.com





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Re: [RE-wrenches] Nabcep Stamp

2011-03-31 Thread Joel Davidson
Greg,

I think some states require designers to have a professional engineering 
license. I know some clients require a licensed engineer with professional 
liability insurance.

You can be rightly proud of your NABCEP certification. It is good that NABCEP 
supports the practitioner concept and encourages life-long learning, but Bill 
Brooks is right. What out for slippery slopes.

Joel Davidson
  - Original Message - 
  From: Greg Egan 
  To: re-wrenches@lists.re-wrenches.org 
  Sent: Thursday, March 31, 2011 9:36 AM
  Subject: [RE-wrenches] Nabcep Stamp


  Bill & Peter,

  Okay, if I have a PE Stamp that means I went to school and worked under a 
mentor for an amount of time to qualify for the PE exam.  Passed the exam and I 
got my stamp.  

  If I have NABCEP certification that means I worked installing solar electric 
systems (in my case) for an amount of time and /or went to school to qualify 
for the NABCEP exam and passed the test. 

  I'm having a hard time seeing the difference here.  If NABCEP provided a 
stamp to it's members that they could use to stamp drawings all it would show 
is that someone who passed the NABCEP exam reviewed the design and hung his or 
her name on the job.  I don't see where NABCEP would be responsible for the 
design anymore than the PE board or whoever is in charge of giving out PE 
stamps would be culpable in a case of a bad design by a PE.

  I think NABCEP should provide a stamp with the certificated member's # on it. 
 All it would do is identify them as a NABCEP member.  My understanding is that 
NABCEP was formed to help the general public distinguish between fly by nights 
and real RE professionals.  A stamp would help do that.  If the city of xyz 
decides that they've seen a lot of good work from NABCEP members and that 
NABCEP certification is good enough for them, what's wrong with that?

  Greg Egan
  Remote Power Inc.
  NABCEP PV Installer



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Re: [RE-wrenches] Value of PV system to a home

2011-03-24 Thread Joel Davidson
Consider not moving or selling your PV powered home. Making your PV powered 
home your retirement home is a better investment than a savings CD and 
definitely a hedge against increased grid electricity prices for retired people 
on a fixed income. Plant some roots and lead your neighborhood by example.

Joel Davidson

  - Original Message - 
  From: Kirpal Khalsa 
  To: RE-wrenches 
  Sent: Tuesday, March 22, 2011 9:33 PM
  Subject: Re: [RE-wrenches] Value of PV system to a home


  What I have been putting forth to our customers and potential customers, is 
that a PV system when looked at like an appliance is simply equal to the value 
of the energy it produces over a given periodfor straight grid tied systems 
I have used what I think is a conservative number of 20 years and then I 
multiply that by today's energy costs...so if a system is installed in 
Oregon and electricity is $.09/kWh and the system is expected to produce 
4500kWh per year then that system would add 4500kWh x $.09 x 20 years = $8100 
in value to their property.in Oregon..
  Certainly you could add average utility price increases over time to the 
value of the energy produced, as well as reductions in system output overtime 
as equipment degrades.additionally if a party is buying a house equipped 
with a PV system they may not want to calculate a full 20 years into that 
formula if the system was installed years earlier...I prefer to use 
conservative numbers in my formula inputs, however the argument could be made 
stating that the 20 year time span is too short and if the lifetime is 
potentially double that the value of the system also doubles. 
  In my mind an off grid system can be more directly tied to the cost of the 
equipment as the grid is not an alternative to the power that is supplied.
  Finally, we have never had a customer disagree with this basic approach, 
however it still falls flat on its face if the customer is not planning on 
moving or selling their property!

  -- 
  Sunny Regards,
  Kirpal Khalsa
  NABCEP Certified Solar PV Installer
  Renewable Energy Systems
  www.oregonsolarworks.com
  541-218-0201 m
  541-592-3958 o


  On Tue, Mar 22, 2011 at 7:44 PM, Exeltech  wrote:

  I spoke last October with the Appraisal Journal, and specifically 
with Rick Nevin,
  author of the referenced articles.

  Mr. Nevin stated a recent review conducted by the Appraisal Journal 
confirmed
  the information in the reports is as applicable today as it was when 
the study
  was conducted, and even more so given the increased cost of energy 
that's
  occurred since the study was published.

  Dan

  --- On Tue, 3/22/11, Jamie Johnson  wrote:


From: Jamie Johnson 
Subject: Re: [RE-wrenches] Value of PV system to a home
To: "Keith Cronin" , "RE-wrenches" 
, "Joel Davidson" 

Date: Tuesday, March 22, 2011, 5:01 PM


Keith & Joel,

The old metric was $20 in value for each $1 saved in energy, 
however the Appraisal Institute has not supported that valuation metric for 
some time now and neither has Fannie, Freddie or FHA.

Using the gross sales price that the customer paid for PV as a 
valuation number was also shot down.

And unfortunately most regional MLS databases don't provide a 
category for solar electric, solar hot water or solar pool heaters, so that 
makes it difficult for an appraiser to use the sales comparison approach.

A year ago I began developing a valuation model for PV for the 
Appraisal Institutes Educational Committee and they are now incorporating parts 
of it into their training programs on "valuation of sustainable buildings" for 
appraisers.  Earlier this year DOE awarded a grant to Sandia Natl Lab to 
essentially do the same thing for the Solar America Cities program (soon to be 
the Solar America Communities program) and they have since picked up my work on 
the valuation model.

A proof of concept spreadsheet (which takes all of the fun out of 
it) and pdf explanation of the valuation model should be released this summer.  
I will provide the download link to the list when it is available.  

It's important to note that any valuation model for PV needs to be 
accepted by Fannie, Freddie and FHA before it is relied on and quoted by the PV 
industry.  There are currently ongoing discussions between FF&F, AI and DOE on 
PV valuations and hopefully they will resolve the PV valuation issues for loan 
transactions soon. 

Jamie Johnson
NABCEP Certified PV Technical Sales Professional PVTS012911-44
NABCEP Certified Solar PV Installer 031310-118

General Manager
SOLAR POWER ELECTRIC






   Original Message 
  Su

Re: [RE-wrenches] Value of PV system to a home

2011-03-23 Thread Joel Davidson
FHA and some other federally funded housing orgs have hardening of the 
arteries. Although EnergyStar has some problems too, they do have mortgages 
that recognize the value of energy efficiency. See 
http://www.energystar.gov/index.cfm?c=mortgages.energy_efficient_mortgages

If anyone doubts the immediate and future value of PV on a home, they can talk 
to the homeowners and realtors in my neighborhood who live with PV (as compared 
to PV wannabes with pv envy).

Joel Davidson

  - Original Message - 
  From: North Texas Renewable Energy Inc 
  To: RE-wrenches 
  Sent: Wednesday, March 23, 2011 6:40 AM
  Subject: [RE-wrenches] Value of PV system to a home


  While the Appraisal Institute model is about the only widespread reference 
point available, it too lacks strong credibility due to the perception that 
it's out dated information and nothing else confirms its conclusion. Many in 
the anti-RE realm point to the fact that F/F&FHA don't support the premise that 
energy saving has real value and use F&F as a valid reason, along with the 
"...no credible evidence" argument, not to. 
  F&F are private mortgage investment corporations that are supported with 
taxpayer money, money that kept them from collapsing under the weight of their 
own bad mortgage investments. Their dislike of any pro-renewable program [PACE 
comes instantly to mind] is grounded in their perception that the low risk 
design that makes PACE so desirable to cities and homeowners is a financial 
risk to the private investors returns. 
  The logic is: homeowner with PV defaults, taxing authority bonds are exempt 
from risk, investment banks are left holding the bag, investors lose pennies. 
  Those investors lobbyists pushed back up the chain of authority to, among 
other things, seriously wound California's own voter approved and taxpayer 
friendly version of PACE. As usual the taxpayers lost much of the the momentum 
that had brought them so close to creating another national standard for 
renewable energy financing without taxpayers having to foot the bill before the 
investment cartel pulled the rug out from under us. 
  The FHA, being nothing more than a hand-puppet for the mortgage industry, 
nodded in agreement and brandished their rubber stamp of approval.
  The factual and irrefutable data proving beyond any doubt that homes & 
businesses with PV are worth more should be an immediate goal for the RE 
industry. While that proof, if it even exists, might not open the investment 
floodgates, it would however open more doors for investors which moves our 
industry a step closer to reaching critical mass.

  my 2¢
  Jim Duncan
  PV installer & financial know-it-all 

From: Jamie Johnson 


Keith & Joel,

The old metric was $20 in value for each $1 saved in energy, 
however the Appraisal Institute has not supported that valuation metric for 
some time now and neither has Fannie, Freddie or FHA.

Using the gross sales price that the customer paid for PV as a 
valuation number was also shot down.

And unfortunately most regional MLS databases don't provide a 
category for solar electric, solar hot water or solar pool heaters, so that 
makes it difficult for an appraiser to use the sales comparison approach.

A year ago I began developing a valuation model for PV for the 
Appraisal Institutes Educational Committee and they are now incorporating parts 
of it into their training programs on "valuation of sustainable buildings" for 
appraisers.  Earlier this year DOE awarded a grant to Sandia Natl Lab to 
essentially do the same thing for the Solar America Cities program (soon to be 
the Solar America Communities program) and they have since picked up my work on 
the valuation model.

A proof of concept spreadsheet (which takes all of the fun out of 
it) and pdf explanation of the valuation model should be released this summer.  
I will provide the download link to the list when it is available.  

It's important to note that any valuation model for PV needs to be 
accepted by Fannie, Freddie and FHA before it is relied on and quoted by the PV 
industry.  There are currently ongoing discussions between FF&F, AI and DOE on 
PV valuations and hopefully they will resolve the PV valuation issues for loan 
transactions soon. 

Jamie Johnson
NABCEP Certified PV Technical Sales Professional PVTS012911-44
NABCEP Certified Solar PV Installer 031310-118

General Manager
SOLAR POWER ELECTRIC






   Original Message 
  Subject: [RE-wrenches] Value of PV system to a home
  From: Keith Cronin 
  Date: Tue, March 22, 2011 2:57 am
  To: RE-Wrenches 


  Hi


  Was wondering if anyone has any new data points on the a

Re: [RE-wrenches] Value of PV system to a home

2011-03-22 Thread Joel Davidson
In general, for every $1/year energy savings add $20 to the home's value.

See http://www1.resnet.us/ratings/overview/resources/appraisal/default.htm

  - Original Message - 
  From: Keith Cronin 
  To: RE-Wrenches 
  Sent: Monday, March 21, 2011 11:57 PM
  Subject: [RE-wrenches] Value of PV system to a home


  Hi


  Was wondering if anyone has any new data points on the additional value a PV 
system adds to the home?


  If someone spends $X for a system and saves $Y a month/year, how is this 
being calculated?


  Do we have actuaries with enough empirical data to suggest what the numbers 
would look like?


  Realizing alot has to do with location, current cost per kWh of electricity 
etc.


  Could have swore there were some studies done to imput the value of two homes 
on the same street, one with solar and one without- for some granular details 
on the delta in values.


  Thanks


  Keith


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Re: [RE-wrenches] Electromagnetic Pulse (EMP)

2011-03-19 Thread Joel Davidson
The subject of EMP comes up from time to time, usually when real catastrophes 
occur or imagined catastrophes are expected to occur. In the 1960s, the US 
military thought that an EMP would affect semiconductors so all the electronics 
at the nuclear missile base where I was stationed had tubes instead of 
transistors. Meanwhile, the civilian world was going solid-state. Sure, you can 
harden your equipment, but no one has ever reported a problem with a PV system 
as the result of an EMP. I'm reminded of a phone call I got in 1984 from a PV 
customer living in southern Utah who called himself a survivalist. He asked how 
his solar module would be affected by an EMP from a nuclear blast. I asked him 
if he planned to watch the end of civilization on his solar powered TV and told 
him to get a life.

Joel Davidson
  - Original Message - 
  From: Drake 
  To: RE-wrenches 
  Sent: Saturday, March 19, 2011 7:53 AM
  Subject: [RE-wrenches] Electromagnetic Pulse (EMP)


  Hello Wrenches,

  I had an inquiry concerning the effect of EMP on photovoltaic systems.  We 
are heading for a period of solar activity that likely will produce this 
effect.  According to a local AEP (American Electric Power) representative, the 
utility is spending a lot of money to counter this anticipated problem.  
Additionally, nuclear related issues are moving back to the front burner.  

  It is clear that the pulse would damage an inverter, but possibly it could be 
put in a Faraday cage.  But a number of questions arise.  
a.. Would the pulse damage the modules?  
b.. Could the large currents and voltages induced by EMP damage the 
conductors in the cells?   
c.. Even if the inverters were surrounded by a Faraday cage, would induced 
currents & voltages from the modules harm the inverters?  
  a.. Would series fuses and surge protectors be adequate protection. 
  Has any research been done in this area?  Does anyone know answers to any of 
these questions?

  Thanks,

  Drake 


  Drake Chamberlin 
  Athens Electric
  OH License 44810
  CO license 3773
  NABCEP Certified PV




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Re: [RE-wrenches] Smart Utility meters

2011-03-07 Thread Joel Davidson
If on-site generator powers all or part of the load and does not send (wheel) 
power backwards to the grid, the utility company cannot detect the on-site 
generator. The kWh consumption reduction will look like you are conserving 
energy or are on vacation and should not attract their attention.

--- On Mon, 3/7/11, William Miller  wrote:


From: William Miller 
Subject: Re: [RE-wrenches] Smart Utility meters
To: "RE-wrenches" 
Date: Monday, March 7, 2011, 10:10 AM


Joel:

It is my understanding that Smart meters will prevent unauthorized (guerilla) 
grid-tie installations from reducing energy costs.  You can still defray your 
costs as long as you don't try to run the meter backwards.  If you do, the 
amount you sell is accounted for as consumption.  Is that your understanding as 
well?

If this is true, Smart meters are not detrimental to approved intertie 
installations.

William Miller



At 07:22 AM 3/7/2011, you wrote:

Smart meters for whom? Smart meters (toll booths) are just another way for 
electric utility companies to increase their revenue and stop customer-owned 
solar power distributed generation. 
-Inline Attachment Follows-


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Re: [RE-wrenches] Smart Utility meters

2011-03-07 Thread Joel Davidson
Smart meters for whom? Smart meters (toll booths) are just another way for 
electric utility companies to increase their revenue and stop customer-owned 
solar power distributed generation. 
  - Original Message - 
  From: Carl Adams 
  To: RE-wrenches 
  Sent: Sunday, March 06, 2011 6:55 PM
  Subject: Re: [RE-wrenches] Smart Utility meters


  William,
  We have run into issues with smart meters. We had a customer in one of the 
pilot neighborhoods. What we saw was the meter registered his production as 
consumption. Effectively doubling his consumption per the meter. After some 
research it was determined that while the new smart meters were indeed net 
metering capable the software back at the reporting station was not net 
metering capable. Solution was to install an old dumb meter which was 
bi_directionally accurate. I hope this helps.

  Cheers Carl
  Sunrock Solar LLC

  On Mar 5, 2011 6:47 PM, "William Miller"  wrote:
  > Friends:
  > 
  > Our local utility (PG&E) is installing smart meters. These will not apply 
  > to interconnected customers because the meter apparently is not capable of 
  > two way metering.
  > 
  > There has been a lot of controversy about smart meters regarding safety, 
  > accuracy and many other issues. Do any of you have any evidence that smart 
  > meters are a problem in any regard?
  > 
  > Thanks,
  > 
  > William
  > 
  > 
  > Please note new e-mail address and domain:
  > 
  > William Miller
  > Miller Solar
  > Voice :805-438-5600
  > email: will...@millersolar.com
  > http://millersolar.com
  > License No. C-10-773985



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Re: [RE-wrenches] NEC 690.11 - Arc Fault Protection ProvisionQuestions ?

2011-03-03 Thread Joel Davidson

A building like a garage or a dwelling for human occupancy?

- Original Message - 
From: "Bill Brooks" 

To: "'RE-wrenches'" 
Sent: Wednesday, March 02, 2011 11:48 PM
Subject: Re: [RE-wrenches] NEC 690.11 - Arc Fault Protection 
ProvisionQuestions ?




Ryan,

690.11 refers to any system that is building mounted--usually roof 
mounted,

but an awning would apply. It is not intended to deal with ground-mounted
systems unless the dc conductors penetrated a building. The intension is
that any PV system associated with a building where people are located 
would

have this extra safety.

Bill.

-Original Message-
From: re-wrenches-boun...@lists.re-wrenches.org
[mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Ryan J
LeBlanc
Sent: Wednesday, March 02, 2011 11:10 PM
To: re-wrenches@lists.re-wrenches.org
Subject: [RE-wrenches] NEC 690.11 - Arc Fault Protection Provision 
Questions

?


Wrenches,

NEC 2011, 690.11 says, "PV Systems with DC source Circuits, DC output
Circuits, or both, on or penetrating a building...at over 80V... Shall be
protected by a listed (DC) arc fault circuit interrupter, PV type, or 
other
system components listed to provide equivalent protection." and then it 
goes

on to say what the arc fault should do.

My questions are:

1) What does "on" mean?

On the roof? attached to the wall?  Say the array is in a field, with
combiner boxes having PV output circuits run underground and stubbed up 
into

the bottom of a DC disconnect mounted to the side of a house.  The conduit
is strapped to the side of the house on it way up to the bottom of the
disconnect switch.  Is this "on" the building?

2) What is a "building"?

Is it a dwelling, small and large commercial buildings?  How about an
enclosed MW in a box solution in the middle of a MW power plant, is that a
building?  I like for example that in the 600V max limitation that it
specifies 1 or 2 family dwellings, leaving small & large commercial
buildings opportunity to have 1000V systems.

Any clarification from Bill Brooks, Matt Lafferty, David Brearly, or the
host of other awesome PV Guru's on the list is extremely appreciated.

~Ryan L

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Re: [RE-wrenches] module / panel

2011-02-09 Thread Joel Davidson
Hi Bill,

The module operated at approximately 450 degree F. When the flame became 
yellow, the PV cell would conduct more and the light power would change the 
orifice size to get the flame back to blue.

There are lots of unusual ways to use cells, modules, and panels. Solar modules 
used as desks, tables, and conference room tables by several PV contractors. 
From my office, I can see a nearby office building with vertically mounted 
solar panels in portrait mode used as screens to hide roof-mounted air 
conditioners. Not very efficient mounting panels at 34 degrees latitude, but 
it's always nice to see more PV.

Here's an interesting solar module as a piece of art. With Valentine's Day 
coming up, you might want to give your honey a solar rose. Tell them Joel 
sentcha. They may give you a discount. See 
http://www.sunbrothers.com/portfolio/flower.htm

Joel Davidson
  - Original Message - 
  From: Bill Loesch 
  To: RE-wrenches 
  Sent: Wednesday, February 09, 2011 5:02 AM
  Subject: Re: [RE-wrenches] module / panel



  Hi Joel,

  Interesting applications.

  I'm not trying to be pedantic but (in the '93 application) did you mean the 
module was seeing the flame and keeping the _gas valve_ open? Do I understand 
correctly that it was capable of keeping the electromagnet energized on only 
pilot flame? Essentially substituting for a thermocouple or thermopile?

  Not exactly an ideal cold temperature application.

  TIA,

  Bill Loesch
  Solar 1 - Saint Louis Solar
  314 631 1094


- Original Message - 
From: Joel Davidson 
To: RE-wrenches 
Sent: Tuesday, February 08, 2011 10:01 PM
Subject: Re: [RE-wrenches] module / panel


Cells? Modules? Bell Labs use to call them solar batteries. Call them what 
you will, but please buy and use them.

Nomenclature from micro to macro: Cell > Module > Panel > Sub-array > Array 
> Power Field.

From Solar Photovoltaic Applications Seminar: Design, Installation and 
Operation of Small, Stand-Alone Photovoltaic Systems, July 1980, 
DOE/CS/32522-T1 (with thanks to Jim Fortenberry for his copy when the DOE shut 
down the PV Division of the Jet Propulsion Laboratory in 1984):
A PV array is composed of many subarrays, panels, modules, and cells in 
various series, parallel, star, and delta combinations. Individual cells are 
wired together and mounted to produce a module.

From UL 1703:
2. Glossary
2.13 Module (Flat-Plate) - The smallest environmentally protected, 
essentially planar assembly of solar cells and ancillary parts, such as 
interconnects and terminals, intended to generate dc power under unconcentrated 
sunlight. The structural (load-carrying) member of a module can either be the 
top layer (superstrate), or the back layer (substrate), in which:
a) The superstrate is the transparent material forming the to 
(light-facing) outer surface of the module. If load-carrying, this constitutes 
a structural superstrate.
b) The substrate is the material forming the back out surface of a module. 
If load-carrying, this constitutes a structural substrate.
2.15 Panel (Flat-Plate) - A collection of modules mechanically fastened 
together, wired, and designed to provide a field-installable unit.

Cell/Module/Panel factoids:

There are such things as non-solar PV cells and modules. In 1983, a UCLA 
researcher used a silicon solar cell to measure the contractions (beats) of a 
heart cell. The heart cell was viewed on a television screen that was connected 
to a microscope. The solar cell was taped to the TV screen. When the cell 
contracted, the photons emitted by the TV screen changed causing the solar cell 
to generate current that was then recorded.

In 1993, while at Solec International, I had a customer who used a small 
custom solar module mounted near the combustion chamber of a natural gas 
heater. The solar module used the photons emitted by the combusted gas to power 
the gas flow regulator.

In 1994, while at Solar Integrated Technologies, I got the first UL listing 
for a photovoltaic panel (not module).

Joel Davidson






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Re: [RE-wrenches] module / panel

2011-02-08 Thread Joel Davidson
Cells? Modules? Bell Labs use to call them solar batteries. Call them what you 
will, but please buy and use them.

Nomenclature from micro to macro: Cell > Module > Panel > Sub-array > Array > 
Power Field.

>From Solar Photovoltaic Applications Seminar: Design, Installation and 
>Operation of Small, Stand-Alone Photovoltaic Systems, July 1980, 
>DOE/CS/32522-T1 (with thanks to Jim Fortenberry for his copy when the DOE shut 
>down the PV Division of the Jet Propulsion Laboratory in 1984):
A PV array is composed of many subarrays, panels, modules, and cells in various 
series, parallel, star, and delta combinations. Individual cells are wired 
together and mounted to produce a module.

>From UL 1703:
2. Glossary
2.13 Module (Flat-Plate) - The smallest environmentally protected, essentially 
planar assembly of solar cells and ancillary parts, such as interconnects and 
terminals, intended to generate dc power under unconcentrated sunlight. The 
structural (load-carrying) member of a module can either be the top layer 
(superstrate), or the back layer (substrate), in which:
a) The superstrate is the transparent material forming the to (light-facing) 
outer surface of the module. If load-carrying, this constitutes a structural 
superstrate.
b) The substrate is the material forming the back out surface of a module. If 
load-carrying, this constitutes a structural substrate.
2.15 Panel (Flat-Plate) - A collection of modules mechanically fastened 
together, wired, and designed to provide a field-installable unit.

Cell/Module/Panel factoids:

There are such things as non-solar PV cells and modules. In 1983, a UCLA 
researcher used a silicon solar cell to measure the contractions (beats) of a 
heart cell. The heart cell was viewed on a television screen that was connected 
to a microscope. The solar cell was taped to the TV screen. When the cell 
contracted, the photons emitted by the TV screen changed causing the solar cell 
to generate current that was then recorded.

In 1993, while at Solec International, I had a customer who used a small custom 
solar module mounted near the combustion chamber of a natural gas heater. The 
solar module used the photons emitted by the combusted gas to power the gas 
flow regulator.

In 1994, while at Solar Integrated Technologies, I got the first UL listing for 
a photovoltaic panel (not module).

Joel Davidson



  - Original Message - 
  From: benn kilburn 
  To: Wrenches 
  Sent: Tuesday, February 08, 2011 2:49 PM
  Subject: [RE-wrenches] module / panel


  Wrenchers,


  Which term do you to describe a single framed unit with either a j-box or two 
wire leads on the back, module or panel? 
  Which term do you believe to be correct and why?


  My interpretation is that a single framed unit is a module.  Any number of 
modules attached to a single detached 'rack' is a panel, and a group of panels 
with the same orientation or mounting location/type is an array.


  If you agree with my interpretation, what are your thoughts on the widespread 
use of the term 'panel' to describe a module.


  thanks,
  benn

  DayStar Renewable Energy Inc.  
  b...@daystarsolar.ca
  780-906-7807 
  HAVE A SUNNY DAY 







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Re: [RE-wrenches] PV encapsulation qualities

2011-02-04 Thread Joel Davidson

Conrad,

Your concern about encapsulation is justified but not just for Chinese 
products. EVA and Tedlar are relatively standard throughout the world. My 
concern is less about the source or the materials and more about process 
time and temperature which are critical in the encapsulation process.


In an effort to be better-faster-cheaper or to differentiate themselves from 
the pack, some manufacturers are using other encapsulants. This is not bad. 
While it is true that not all change is for the better, nothing gets better 
without change. Your choices are clear: buy tried-and-true technology from 
well-established companies and hope that they continue to practice good 
quality control and/or take the risk and buy innovative technology. I do 
both with open eyes and an open mind and have rarely been burned.


Joel Davidson

- Original Message - 
From: "Conrad Geyser" 

To: "'RE-wrenches'" 
Sent: Friday, February 04, 2011 8:33 AM
Subject: [RE-wrenches] PV encapsulation qualities



Esteemed wrenches,

As the Chinese invasion continues, I imagine that most of us will end up
using products made in China at some point.

Most of my experience and knowledge has indicated the Chinese modules are 
by
and large going to be of comparable quality to any other crystalline 
silicon

module.  The one aspect that I haven't seen much information on is the
encapsulation.

Anyone up on their Tedlar & Tedlar substitutes?  All the Tedlar that I've
known from 80's exterior pipe insulation has truly been amazingly durable
stuff even in direct sunlight.  The stuff typically is still holding up 30
years later.  But now I've been stymied by trying to get backing and
encapsulation information out of manufacturers no matter where they are. 
I

am very nervous that less expensive substitution will lead to premature
failure of backing or other encapsulation points.  I've seen too many
plastics undergo breakdown with age to not be nervous.

My concern for a early February day...

Conrad
Cotuit Solar

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[RE-wrenches] Multi-MW PV Maintenance

2011-02-02 Thread Joel Davidson

Hello Wrenches,

I have experience performing periodic inspection, maintenance, and cleaning 
of roof-mounted arrays up to 500 kW and smaller ground-mounted arrays, but 
no experience maintaining and cleaning multi-MW ground-mounted arrays. Any 
experiences you can share would be appreciated. Does someone have a written 
procedure?


I would think that first, a review of past performance and any troubles and 
repairs would be in order. Then walking or using a slow-moving vehicle like 
an open golf cart going up and down the rows would be a good way to make a 
preliminary inspection. Stopping and spot-checking fasteners, wiring, and 
connections would be required. Opening up and inspecting cabinets and 
equipment enclosures would be needed. Then using a mobile sprayer to clean 
the subarrays while keeping radio contact with someone monitoring the array 
for current and voltage fluctuations (sort of megging for faults). What do 
you think?


Joel Davidson 


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Re: [RE-wrenches] Roofers installing solar = creative, new installation methods

2011-01-28 Thread Joel Davidson
Andrew,

Carter era contractors did not kneecap alternative energy industry in the 
1970s, but that's not a wrenches subject.

Sure, everyone has stories about bad customers, GCs, subs, equipment, etc. Some 
of us are honest enough to admit that we have made a mistake or two. You don't 
have to work for or with people you don't like or buy equipment you don't like. 
But I don't know anyone in the building or energy industry who does not work 
with others.

Few contractors nowadays do all the trades in-house. Do you sub out structural 
engineering, surveying, roofing, arborist, concrete cutting, crane, etc.? Then 
what's wrong with you being a sub if you like the other guy's work and can 
control design and electrical installation or whatever you need to control? 
There are plenty of decent contractors in your service area who would like to 
have a good go-to PV company just as you like to have good go-to roofer. You 
know your design and electrical costs and what margin you need for that portion 
of your work. So what's the hassle?

Joel Davidson
  - Original Message - 
  From: Solar Energy Solutions 
  To: RE-wrenches 
  Sent: Friday, January 28, 2011 8:41 AM
  Subject: Re: [RE-wrenches] Roofers installing solar = creative,new 
installation methods


Joel,

Our company cannot survive without selling an entire system.  When we 
help the unqualified and untrained we legitimize unsubstantiated pv businesses. 
 We get  a dozen phone calls a month from folks wanting us to install their 
systems.  It is a rat hole and we have learned that not only are such ventures 
unprofitable, they are fraught with poor designs and a plethora of other 
hassles.  This whole thing reminds me of the Carter solar Gold Rush where, 
sure, a bunch of systems were installed, but look at the damage it did to the 
industry.

Respectfully, 



Andrew Koyaanisqatsi
President
Solar Energy Solutions, Inc.
Since 1987,
Moving Portland and Beyond 
to an Environmentally Sustainable Future.
503-238-4502
www.solarenergyoregon.com 

"Better one's House too little one day
than too big all the Year after."


--- On Fri, 1/28/11, Joel Davidson  wrote:


  From: Joel Davidson 
  Subject: Re: [RE-wrenches] Roofers installing solar = creative, new 
installation methods
  To: "RE-wrenches" 
  Date: Friday, January 28, 2011, 7:06 AM


  Guys,
  You're missing a business opportunity. Instead of complaining about 
roofers' bad work and competition, show the company owners photos of their 
screw-ups and your quality work. Tell him that he is a risk. Then offer to do 
their design and electrical installation (let them do the sales, roofing, and 
grunt work).
  Joel Davidson
- Original Message - 
From: Warren Lauzon 
To: RE-wrenches 
Sent: Friday, January 28, 2011 3:35 AM
Subject: Re: [RE-wrenches] Roofers installing solar = creative,new 
installation methods


We have seen a lot of the roofing companies nibbling around the 
edges of solar installs lately. I have only seen a couple of installs 
personally, and they were far from what I would call professional or reliable. 
Not quite as bad as your example, but in one case they had used Romex to run 
the wiring down to the inverter, and not in conduit.


From: Nick Soleil 
Sent: Thursday, January 27, 2011 8:11 PM
To: re-wrenches@lists.re-wrenches.org 
Subject: [RE-wrenches] Roofers installing solar = creative,new 
installation methods

Hi wrenches:
   Have you noticed that roofing companies have recently been 
trying to sell solar?  One company thought of something that I had never 
considered.  Listen to this neat story.
   I was servicing a job today, where a roofing company recently 
removed and re-installed a PV array on a 12 degree sloped roof.  The funny 
thing is that the roofer didn't want to penetrate his new roof, so he and the 
customer decided to leave the panels sitting on the composition roof without 
any attachments to the structure.  They didn't think it was necessary!  
Shortly afterward, the array slid down the roof, and a 
MultiContact connector came unplugged.  The customer noticed that his system 
was not operating, and called us to the site.  


Nick Soleil
Project Manager
Advanced Alternative Energy Solutions, LLC
PO Box 657
Petaluma, CA 94953
Cell: 707-321-2937
Office: 707-789-9537
Fax: 707-769-9037 





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Re: [RE-wrenches] Roofers installing solar = creative, new installation methods

2011-01-28 Thread Joel Davidson
Guys,
You're missing a business opportunity. Instead of complaining about roofers' 
bad work and competition, show the company owners photos of their screw-ups and 
your quality work. Tell him that he is a risk. Then offer to do their design 
and electrical installation (let them do the sales, roofing, and grunt work).
Joel Davidson
  - Original Message - 
  From: Warren Lauzon 
  To: RE-wrenches 
  Sent: Friday, January 28, 2011 3:35 AM
  Subject: Re: [RE-wrenches] Roofers installing solar = creative,new 
installation methods


  We have seen a lot of the roofing companies nibbling around the edges of 
solar installs lately. I have only seen a couple of installs personally, and 
they were far from what I would call professional or reliable. Not quite as bad 
as your example, but in one case they had used Romex to run the wiring down to 
the inverter, and not in conduit.


  From: Nick Soleil 
  Sent: Thursday, January 27, 2011 8:11 PM
  To: re-wrenches@lists.re-wrenches.org 
  Subject: [RE-wrenches] Roofers installing solar = creative,new installation 
methods

  Hi wrenches:
 Have you noticed that roofing companies have recently been trying to sell 
solar?  One company thought of something that I had never considered.  Listen 
to this neat story.
 I was servicing a job today, where a roofing company recently removed and 
re-installed a PV array on a 12 degree sloped roof.  The funny thing is that 
the roofer didn't want to penetrate his new roof, so he and the customer 
decided to leave the panels sitting on the composition roof without any 
attachments to the structure.  They didn't think it was necessary!  
  Shortly afterward, the array slid down the roof, and a MultiContact 
connector came unplugged.  The customer noticed that his system was not 
operating, and called us to the site.  


  Nick Soleil
  Project Manager
  Advanced Alternative Energy Solutions, LLC
  PO Box 657
  Petaluma, CA 94953
  Cell: 707-321-2937
  Office: 707-789-9537
  Fax: 707-769-9037 





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  Northern Arizona Wind & Sun - Electricity from the sun since 1979
  
  Online Solar Store
  Free Solar Discussion Forum
  



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Re: [RE-wrenches] Incompatible Metals

2011-01-15 Thread Joel Davidson

Here is a good powerpoint presentation about galvanic corrosion.
www.rose-hulman.edu/~stienstr/me%20328/Day_36.ppt

- Original Message - 
From: "Hugh" 

To: "RE-wrenches" 
Sent: Saturday, January 15, 2011 2:46 PM
Subject: Re: [RE-wrenches] Incompatible Metals



>Hi Kelly:
Are you sure about the XHHW listing.  Doesn't that designate aluminum 
wire?  You mentioned CU before.
I have seen some discolloration from copper wire against module 
frames, but not real corrosion.


The way I understand galvanic corrosion is that it is produced by a 
current as in a battery, and if the base metal side of the equation is 
large in area, and the noble metal is small then the effect is diluted. 
If you use aluminium rivets in a copper vessel then they might disappear 
fast, but copper rivets will have little effect on an aluminum vessel.  So 
much for the theory anyway.

--
Hugh Piggott

Scoraig
http://www.scoraigwind.co.uk
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[RE-wrenches] Galvanic corrosion

2010-12-30 Thread Joel Davidson

Wrenches,

Galvanic corrosion has been discussed before, but I am hoping that you all 
have come up with better, faster, cheaper ways to fasten and ground aluminum 
framed modules to steel and galvanized steel mounting structures. I am 
particularly interested in how to effectively and permanently ground 
aluminum framed modules to galvanized steel and - ready for the big 
challenge - getting the AHJ's approval.


Best wishes for another wonderful year of fun in the sun.
Joel Davidson 


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Re: [RE-wrenches] Low grid voltage fix

2010-12-21 Thread Joel Davidson
Dan,

Thank you for the quick reply. I have been using the 108 VAC default setting 
since 1998. I'll try 95 VAC.

It is interesting to hear other wrenches comment on utility low and high 
voltage. Power factor control is another challenge for some utility companies. 
On the other hand, they hold the RE industry to very tight power quality 
standards. I have tried to get Los Angeles Department of Water & Power (LADWP) 
and Southern California Edison (SCE) to keep their voltage within spec and 
improve their power factor. Their responses are similar to asking City Hall to 
fix potholes in the road. Sometimes they do. Sometimes they don't get a round 
tuit for a while. SCE power is generally ok except in old neighborhoods with 
wires and transformers over 40 years old. Forget about LADWP. They are off on 
another planet. The smaller municipal utilities in southern California are 
pretty good at managing power quality. Fortunately, today's inverters can be 
adjusted manually. Perhaps some day inverters and loads will self-compensate 
for less than stellar grid power quality.

Happy Holidays!
Joel Davidson
  - Original Message - 
  From: d...@foxfire-energy.com 
  To: RE-wrenches 
  Sent: Sunday, December 19, 2010 2:54 PM
  Subject: Re: [RE-wrenches] Low grid voltage fix


  Try menu 11.. Ac input.




  Dan Brown
  Foxfire Energy Corp.
  Renewable Energy Systems
  (802)-483-2564
  www.Foxfire-Energy.com
  NABCEP #092907-44



 Original Message 
Subject: [RE-wrenches] Low grid voltage fix
From: "Joel Davidson" 
Date: Sun, December 19, 2010 12:24 pm
To: "RE-wrenches" 

Wrenches,

It's Christmas time again in Southern California Edison (SCE) territory 
which means low insolation and high regional electric consumption. Every 
night SCE voltage drops to around 105 VAC or lower. Our grid-tie SW4048 
inverter sees SCE's low voltage as a brownout and switches to autonomous 
mode which is normal. However, we have only 4 kWh of battery storage so the 
combination of nightly brownouts and a series of cloudy days eventually 
depletes our battery bank causing the inverter to do a low-voltage shut 
down 
which is normal. Power goes off in our home and we have to switch over to 
SCE power, reset the inverter, and wait until the battery bank is 
recharged. 
How do we set the SW4048 to accept as low as 100 VAC from the grid before 
    switching to autonomous mode?

Joel Davidson 

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[RE-wrenches] Low grid voltage fix

2010-12-19 Thread Joel Davidson

Wrenches,

It's Christmas time again in Southern California Edison (SCE) territory 
which means low insolation and high regional electric consumption. Every 
night SCE voltage drops to around 105 VAC or lower. Our grid-tie SW4048 
inverter sees SCE's low voltage as a brownout and switches to autonomous 
mode which is normal. However, we have only 4 kWh of battery storage so the 
combination of nightly brownouts and a series of cloudy days eventually 
depletes our battery bank causing the inverter to do a low-voltage shut down 
which is normal. Power goes off in our home and we have to switch over to 
SCE power, reset the inverter, and wait until the battery bank is recharged. 
How do we set the SW4048 to accept as low as 100 VAC from the grid before 
switching to autonomous mode?


Joel Davidson 


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Re: [RE-wrenches] Battery based hydrogen incidents

2010-12-17 Thread Joel Davidson
Here's a true story about another foolish but lucky guy. My Arkansas Ozark 
Mountain neighbor had a big 115 VDC windcharger and a battery bank of large 
2-volt cells inside a shed at the base of his 85 feet tower. One day he opened 
the door with a smoke in his mouth. The H2 (not the batteries) exploded, 
rocketing him out the door, and knocking him on his ass. He was a big, strong 
guy and didn't get hurt, but he swore he would never smoke around batteries 
again. (Preventive action - ventilate battery room before entering.)

  - Original Message - 
  From: Luke Christy 
  To: re-wrenches@lists.re-wrenches.org 
  Sent: Thursday, December 16, 2010 7:52 AM
  Subject: Re: [RE-wrenches] Battery based hydrogen incidents




  These descriptions of battery explosions certainly drive home the point that 
one should always always wear protective gear when working on batteries.


  I have  a story that may take the prize for the most foolish behavior yet 
described (thankfully I wasn't involved until the cleanup stage).
  In 2008 a neighbor of mine was filling a bank of 12 L-16s installed in a 
remote home here in So. Colorado. Apparently it didn't occur to him that it 
probably wasn't a good idea to smoke while adding water to gassing batteries. 
Two or three batteries into the job, sure enough, a spark fell off his lit 
cigarette, probably landed in or near the open cap of the cell he was filling, 
and the resulting explosion blew the top off of the L-16, also spraying 
electrolyte everywhere in the battery room. My neighbor (who shall remain 
nameless) was not wearing protective gear of any kind, and of course he had 
acid in his eyes and all over his face. He was alone at this house, 40+ miles 
from the nearest town, and close to ten miles from the closest neighbor. He 
managed to wash his eyes and face in a creek, and was somehow able to drive the 
ten miles to the neighbor's house, who then took him to a hospital. Amazingly, 
he came out of it without permanent eye damage or scarring, but that must be 
due to having had more than his share of luck that day.


  I had the job of cleaning up the mess and replacing the blown-up battery. One 
thing that stood out was the fact that the top of the battery disintegrated 
into dozens of very sharp shards of plastic. These were obviously thrown out 
with the explosion and could have easily caused serious injury themselves. The 
entire wall of the battery room was covered with tiny bits of plastic, plate 
particles, and electrolyte, almost making a cartoon-like outline of my 
neighbor, as he had been standing in front of the wall when the battery blew.


  Always wear your eye protection. (and it seems that smoking plus hydrogen 
equals bad things).




Luke Christy 

 NABCEP Certified PV Installer™: Certification #031409-25 (Luke Christy)
 CoSEIA Certified PV Installer (Luke Christy)

Solar Gain Services, LLC
Monte Vista, CO.
sgsrenewab...@gmail.com










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Re: [RE-wrenches] Battery based hydrogen incidents

2010-12-15 Thread Joel Davidson
I have sold thousands of off-grid PV systems and hundreds of on-grid PV systems 
with batteries. In 1984, one customer located 30 miles north of New Orleans 
with an off-grid PV system and T-105 batteries reported that a battery 
exploded. The cause was a clogged cell cap vent that trapped H2 that was 
ignited by transient current from a nearby lightning strike (that also 
destroyed his charge controller). About 6 months later another nearby lightning 
strike fried another controller. The PV array was a few hundred feet from the 
home. The owner wired the PV array and home equipment ground rods together and 
made sure that cap vent holes were kept clean. Subsequent lightning storms 
caused no problems.

The only exploded battery that I actually saw was also in the 1980s at a Sears 
service station. An automobile battery had exploded and tore a hole in the car 
engine hood.

Joel Davidson

- Original Message - 
  From: Dana 
  To: 'RE-wrenches' 
  Sent: Wednesday, December 15, 2010 8:10 AM
  Subject: [RE-wrenches] Battery based hydrogen incidents


  Ken - 

   

  To meet the flow have run 2 and 3 fans to meet the flow. 2" output from the 
fan into a 4" header with a matching 2.5" inlet as far away on the lowest 
portion of the battery box.

   

   

  In 22+ years in off grid installations I have yet to see or even hear of one 
hydrogen explosion. I get repeatedly asked why we have to go to the efforts we 
go to for box and venting. I am not able to provide even one incident that I 
have heard rumor of.

   

  Q - How many battery based hydrogen incidents have happened in our collective 
experience?

   

   

   

  Dana Orzel

  Great Solar Works, Inc

  E - d...@solarwork.com

  V - 970.626.5253

  F - 970.626.4140

  C - 970.209.4076

  web - www.solarwork.com

   

  "Responsible Technologies for Responsible People since 1988"

  Do not ever belive anything, but seriously trust through action.

   

  From: re-wrenches-boun...@lists.re-wrenches.org 
[mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Kent Osterberg
  Sent: Tuesday, December 14, 2010 12:07 PM
  To: Wrenches
  Subject: [RE-wrenches] Battery Venting

   

  Fellow Wrenches,

  The discussion about battery venting reminds me of a useful and inexpensive 
program, BattMV, for determining ventilation requirements per EN-50272.  
EN-50272 is a European standard used to determine how much air flow is needed 
for a room, I don't know of a equivalent standard used in the U.S.  It takes a 
surprising amount of ventilation.  For a 400-AH 48-volt L16 bank charged at 
57.6 volts and 24 amps, it's about 7 CFM just to keep the %H2 down to 4%.  A 
12-volt Zephyr vent is good for about 5 CFM!   If you think you are venting 
enough, take some time and study this issue.

  Kent Osterberg
  Blue Mountain Solar



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Re: [RE-wrenches] To insulate a battery bank DEPENDS on a lot offactors.

2010-12-12 Thread Joel Davidson
Insuating batteries does not have to be complicated. Several years ago, a 
Minnesota man (can't recall his name) who worked for the Jacobs brothers at 
their Wind Electric Company in the 1930's told me how he insulated his glass 
case Edison cells. He kept his battery bank outdoors on boards and covered with 
a tarp. Before the first snow, he would heap a big pile of loose hay on the 
tarp and then cover the whole hay pile and batteries with another tarp. Between 
winter storms he would lift the tarps and hay to check his batteries and add 
water if needed. He said he stored his potatoes and other root crops that 
didn't fit in his root cellar the same way. He and other old-timer in 
Massachusetts who also had Edison cells told me that they would dump out the 
electrolyte every 5 years and clean the jars and plates with plain water and 
add fresh electrolyte. The gentleman in Massachusetts bought his batteries from 
Mr. Edison in 1935 and was still using them in the early 1980s when he bought 
Arco ASI 16-2000 modules. Sensible people. Simpler times.

Joel Davidson
  - Original Message - 
  From: Dana 
  To: 'RE-wrenches' 
  Sent: Sunday, December 12, 2010 3:13 PM
  Subject: [RE-wrenches] To insulate a battery bank DEPENDS on a lot offactors.


  Great discussion and Thanks to all of you for the input.

   

  I thought of attempting a  wrap up of the various presentations but there are 
and always will be many variables in battery storage and insulation 
requirements. Here are my thoughts and a distillation from you all with respect 
to my high elevation climate in W. CO. - 6 months of winter and cool nights in 
summer [typically].

   

  Type of battery - Wet VS. Sealed batteries. : depends on size and usage of 
system and client choice.

   

  Climates – 4 season with 5-6 months of winter like conditions VS. a mild year 
round costal climate. : A long winter climate can seriously chill a poorly 
insulated bank and therefore reduce capacity when the bank get cold. I get more 
calls each Nov. from new to off grid folks with an under sized array and cold 
battery bank about reduced capacity.

   

  Does it cool off at night in the summer? VS. It is hot  24/7 for 4 months?

   

  Size of bank – Small VS. Large. : Smaller reacts more quickly to a cooling or 
heating trend VS. Larger react slowly.

   

  Ambient building temperature. – heated building VS. walled in shed/free 
standing battery box in a snowy scenario. : If I can put the bank on a 
temperature controlled radiant concrete slab I do so.

   

  Ability to sink the battery bank into the ground VS. not being able to do so. 
: installation & cost can be a challenge here.

   

  Powered venting VS.  convective venting ; Powered with a back draft damper 
seems to be a better option in winter climates. I have used the Zephyr 
Industries powered vent with backdraft damper for many years with great success.

   

  As mentioned batteries are an electrochemical unit that requires, like us, a 
narrow window for temperature to exist and operate efficiently. When working 
hardest, typically during winter, the recharge requirements are high and the 
hours of sunlight are low, therefore the temperature window is best on the 
warmer end of the range. 

   

  The time of year when power requirement can be lowest in summer, the usage is 
lower due to long days and lack of heating systems drawing them down over 
night, unless you are irrigating and perhaps a PV direct design would then be 
best.

   

  Thanks all.

   

   

  Dana Orzel

  Great Solar Works, Inc

  E - d...@solarwork.com

  V - 970.626.5253

  F - 970.626.4140

  C - 970.209.4076

  web - www.solarwork.com

   

  "Responsible Technologies for Responsible People since 1988"

  Do not ever belive anything, but seriously trust through action.

   

  From: re-wrenches-boun...@lists.re-wrenches.org 
[mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Joel Davidson
  Sent: Sunday, December 12, 2010 11:59 AM
  To: RE-wrenches
  Subject: Re: [RE-wrenches] To insulate a battery bank -- sort of

   

  First of all, there is no one solution to battery selection, installation, 
operation, and maintenance. One size does not fit all. Allan and other wrenches 
with lots of battery experience have a good understanding about batteries in 
their regions for their customers.

   

  Second, insulation is used to control temperature change. Insulation slows 
both heat loss and gain. Large battery banks tend to change temperature slowly 
due to their mass and may not need insulation in your region or in a specific 
installation. The goal is to keep the battery bank at its optimum temperature. 
Cold batteries have reduced capacity. 40 F (4.4 C) is too cold for almost all 
RE system batteries. Hot batteries have shorter lives. Heat affects both 
battery chemistry and materials. For example, the plastic around Absolyte 
terminals cracks if their

Re: [RE-wrenches] To insulate a battery bank -- sort of

2010-12-12 Thread Joel Davidson
First of all, there is no one solution to battery selection, installation, 
operation, and maintenance. One size does not fit all. Allan and other wrenches 
with lots of battery experience have a good understanding about batteries in 
their regions for their customers.

Second, insulation is used to control temperature change. Insulation slows both 
heat loss and gain. Large battery banks tend to change temperature slowly due 
to their mass and may not need insulation in your region or in a specific 
installation. The goal is to keep the battery bank at its optimum temperature. 
Cold batteries have reduced capacity. 40 F (4.4 C) is too cold for almost all 
RE system batteries. Hot batteries have shorter lives. Heat affects both 
battery chemistry and materials. For example, the plastic around Absolyte 
terminals cracks if their temperature is repeatedly 90 F (32.2 C) which can 
happen in an uninsulated battery area in the southwest U.S. So too hot or too 
cold is not good.

Third, batteries need ventilation to safely remove hydrogen. Surprisingly, what 
most people consider a small amount of battery ventilation will suffice unless 
the battery bank is being charged excessively. For example, a PV system with 
eight 100 watt modules (rated 17.1 V, 5.88 A) and sixteen 6-volt batteries is 
wired for 24 volts DC. The required venting is 0.0135 x (5.88 x 4) x 12 = 3.81 
CFM or 228.6 cubic feet per hour. Many, if not most, rooms are 8 feet in height 
with 2 air changes per hour. A room 8’ x 6’ x 6’ has 288 cubic feet volume and 
naturally vents 576 cubic feet per hour, almost 2.5 times the required 288.6 
cubic feet per hour.

In general, a battery area, room, box, etc. should be kept at 70 F (21.1 C), 
have good ventilation, no open flames (heater, gas water heater nearby?), no 
electrical sparks (automatic igniters, etc.?), easy to maintain and inspect, 
tidy, out of reach of non-authorized personnel, and have an up-to-date fire 
extinguisher handy.

Batteries operate by electro-chemical process almost like living things. If 
they are too hot or too cold, they perform poorly and can die. If they are not 
fed properly (charged correctly), they will die. Interestingly, we use 
expressions like "die" and "end of life" to describe these non-living things. 
Most wrenches know people who party all weekend, don't eat well, forget to 
dress properly for the weather, and get sick. Likewise, if a battery bank is 
deeply discharged, not properly recharged, and too hot or too cold, it will 
perform poorly and die prematurely. You get the picture.

Lastly, we have learned a lot about batteries in the 200 year since physicist, 
Allessandro Volta, developed the first cells. Unfortunately, a lot of battery 
myths exist. Explode myths (but not batteries) by asking the "5 whys". See 
http://en.wikipedia.org/wiki/5_Whys

Joel Davidson
  - Original Message - 
  From: d...@foxfire-energy.com 
  To: RE-wrenches 
  Sent: Saturday, December 11, 2010 5:32 PM
  Subject: Re: [RE-wrenches] To insulate a battery bank -- sort of


  Ok, I'm a little reluctant to kick this critter much.. because I feel like I 
must be missing something here... but let me float this notion.. If we stuff 
flammable gas producing batteries in an enclosure (and proceed to button them 
up tighter than a bull's ass in fly season -- fan or no fan), Haven't we just 
created a Class I Division 1 location? (NEC 500.5).  then say we do rely on a 
$4. fan (OK -- $15.) to declassify as allowed in 500.5(A)fpn,  Wouldn't we 
still have a Class I Division 2 location? NEC 500.5(B)(2)(2)/(3). So my point 
is -- are fully enclosed battery boxes really worth the hassle? are they even A 
good idea? I can't seem to find where NFPA 70 "Requires" a battery enclosure.. 
690 VIII  says you need to protect electrical connections (in dwellings) and 
kicks you back to 480, but makes no mention of "requiring" a battery 
enclosure.. 480.8 says basically that if you use racks or trays, they've got to 
hold up. 480.9 outlines ventilation and working space, but again doesn't 
"require" enclosures. (480.6 deals with Insulation of batteries.. But I'm 
thinking they're talking about electrical insulation)... But nowhere in the NEC 
have I found any mention of battery boxes or Enclosures being "Required"..  On 
the contrary, Seems to me they're suggesting that if by design you can provide 
for proper work space, adequate ventilation (both out and in) and protect the 
electrical connections, you're good as far as NEC is concerned.. In NFPA 70E, 
(Workplace Safety) 320.4 says batteries should be under lock and key (or 
require a tool for access), and that they be protected both physically and 
electrically.  also in NFPA 70E, 320.6 kicks around enclosure requirements 
some, but seems to focus more on protecting terminals and related equipment..  
Now in 

Re: [RE-wrenches] To insulate a battery bank

2010-12-11 Thread Joel Davidson
I recommend insulation. In general, operating temperature is very important. 
Batteries last longer if kept cool. However, a battery below 60 degrees F (15.5 
C) has reduced capacity. Temperatures above 77 F (25 C) increase capacity only 
slightly but they significantly reduce battery life. Batteries operating 
regularly above 85 F (29.4 C) lose have their operating life.
Joel Davidson
  - Original Message - 
  From: bob ellison 
  To: 'RE-wrenches' 
  Sent: Friday, December 10, 2010 3:32 AM
  Subject: Re: [RE-wrenches] To insulate a battery bank


  With the amount of lead in a battery bank it changes temperature very slowly. 
Both gaining and losing heat is a very slow process.

  I have never insulated battery banks, if in a cold area like here we size 
them larger for the slower reaction time in the winter anyway. Part of the 
reason being that I would bet that the acid would raise hell with the 
insulation! 

  We regularly see battery banks that are 40 degrees or so it presents no 
problem.

  If the exhaust fan is running in a 70 degree building all it does is draw the 
warm air over the top of the battery and not really warm them much anyway, in 
an unheated building it will probably not make much difference.

  The only way that I would put insulation in an unheated battery box is on the 
outside of the plywood, away from the acid and gasses. I would also make it 
removable in the summer.

   


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[RE-wrenches] Internet-based monitoring

2010-11-25 Thread Joel Davidson

Hello Wrenches,

The subject of PV system monitoring has been discussed before, but I want to 
get your latest recommendations. I have over 50 commercial PV systems in 
several states that I want to monitor on computers both at the site and at 
one central location. Some sites have more than one PV system. What 
internet-based PV monitoring system for multiple commercial PV systems have 
you found to be reliable, provides useful information for identifying 
problems and trouble-shooting, and is reasonably priced? What other 
attributes should I be looking for? And what should I avoid? Thanks in 
advance for your practical and sage advice.


Joel Davidson

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Re: [RE-wrenches] Megger for array testing

2010-11-18 Thread Joel Davidson
Perhaps someone has an electronic copy of "Field Wet Resistance Test" revised 
7/18/94 that was developed by the PVUSA Project, PG&E, and Bechtel that they 
could share with the group.

Joel Davidson


- Original Message - 
  From: Matt Lafferty 
  To: 'RE-wrenches' 
  Sent: Wednesday, November 17, 2010 6:29 PM
  Subject: Re: [RE-wrenches] Megger for array testing


  Hi Drake,

  Disclaimer #1: i do not recommend megger-testing an array (or module or 
string) unless you have an approved procedure from the module manufacturer for 
the installed configuration. 
  Disclaimer #2: i am not the foremost authority on the list for this topic... 
Mr. Brooks? (Note: Bill's post just came in, but i want to share this anyway)

  i have, however, conducted these tests, as part of the commissioning 
requirements, on about a dozen systems which were installed under R&D grants. 
Back in the day, pretty much all systems bigger than 4 or 5 kilowatts were 
required to be megger tested, if they were "on the radar" in any way. This was 
a function of the fact that public dollars were being spent in the HOPE that PV 
could some day become a mainstream technology. And the fact that PV modules 
were so expensive. The combination of these factors meant that, in any 
meaningful sense, only projects that received subsidies were built, and grant 
requirements were in play. One of the conditions was that these tests be 
performed. This is a logical requirement in many ways. 

  Each system, that i've done this on, was different from the others. In each 
case, the procedure and analysis methodology was different. Sufficiently 
different, that i learned early on to NOT MAKE UP MY OWN PROCEDURE. 
Manufacturer procedures varied in lead placement, array sections to be tested, 
surface wetting techniques, test voltages, temperature compensation, and 
Pass/Fail values. i've made up lots of procedures over the years, but i'm not 
touching this one. I don't understand it well enough.

  The basic theme and theory was the same, pretty much across the board. But 
the actual methods... The steps... They were different. The very limited 
information i was able to extract from manufacturers' engineers varied. Some 
warned about reverse-biasing diodes and others didn't think it was a concern. 
Some insisted that test-lead arrangement was super-critical and others didn't. 
Some wanted to test at voltages lower than the system voltage and others said 
1kV was fine on a 500V circuit. Some wanted to connect one pole to ground. Most 
didn't.

  Applying test voltages to, and measuring the resistance of, an installed, 
illuminated source circuit or array, is very different than applying test 
voltages to, and measuring resistance of, a single, unilluminated and shorted 
module. Myriad additonal factors and considerations must be accounted for. 

  My observation is that at least half of the manufacturers' engineers were 
only guessing, and crossing their fingers that everything would be fine after 
performing megger testing on a source circuit or array. Another observation is 
that at least half of these engineers had never contemplated megger-testing an 
array as a completed system... Only as a single module within the hi-pot test 
regime for manufacturing and listing purposes. As a group, they all were 
resistant to provide a documented procedure and acceptable test values. None, 
as in Z-E-R-O, were able to predict actual test results with any reasonable 
degree of accuracy. As in, off by megohms in many cases. Even though the 
subjects under test were designed, and largely manufactured, by their 
companies. Even though these guys were responsible for the actual system 
design, in most cases. Even though my experience leads me to believe these guys 
are at least half full of crap, i do believe this test is valid and has merit. 
i believe that all arrays should be tested for their dielectric resistance 
during the commissioning process, in fact.

  If we are going to megger our field-installed conductors... And we absolutely 
should be... It's a simple step. In order to do this, as an industry, we just 
need a better understanding of the characteristics and test procedures. My 
requests that manufacturers publish a procedure for each module they make, with 
acceptable test results in common circuit configurations, have resulted in 
squat. Going forward, i hope somebody forces them to do it, 'cause they ain't 
likely to bother otherwise.

  Under controlled conditions, such as those found during module manufacturing, 
predicting a test result within a reasonable degree of accuracy has a much 
higher chance for success than a prediction under uncontrolled conditions in a 
multi-subject combination. I get that. Nevertheless, we are deploying these 
products into an installed configuration. There is shipping to the distributor. 
Shipping to t

Re: [RE-wrenches] Megger for array testing

2010-11-17 Thread Joel Davidson
Hello Drake,

I think you should talk to a Sanyo Solar engineer to get accurate information. 
Every Sanyo and other brand UL listed modules must be dielectric 
voltage-withstand factory tested to 2 times system voltage plus 1,000 volts. I 
hi-pot test modules in the factory at 3,000 volts so they will meet UL and also 
IEC standards. I megger field test arrays at 1,000 volts to find module, 
connector, and wiring problems. Megging at 500 volts is ok, but it may not 
reveal wire insulation problems.

Joel Davidson

  - Original Message - 
  From: Drake 
  To: RE-wrenches 
  Sent: Wednesday, November 17, 2010 7:36 AM
  Subject: [RE-wrenches] Megger for array testing


  Hello Wrenches,

  Looking through the archives on using a Megger  for testing modules, it 
appears that it is best to keep voltages to 500VDC.  I read all that I could 
find. 

  Talking to a Sanyo representative, I was told that keeping test voltage under 
600 would not void the warranty or be an issue with UL.  He said they have 
tested Sanyo modules up to 1000 VDC with no problems.

  As a final test on a system, I want to Megger test the array from the 
terminations at the inverter.  The approach I'd plan to use is: 
a.. Clamp the Fluke 1587 negative to the enclosuer ground. 
b.. Put the positive test lead to the negative conductor from the array and 
test 
c.. Put the positive test lead to the positive conductor from the array and 
test 
  All tests would be done at 500 V.  The modules are illuminated, but there is 
no significant reading from either positive or negative terminal to ground. 
a.. The conductors would be removed from their terminals at the inverter 
and be in free air. 
b.. The conductors would be continuous through the string of 10 Sanyo 210 
modules. 
  My questions are: 
a.. Does anyone see a problem in this approach? 
b.. Since the array often has 500 VDC open circuit readings and shows no 
indication of a fault whatever, would this test accomplish anything more than 
the standard voltage to ground tests I've already done? 
c.. Is there any danger to diodes or other PV components? 
  Thanks in advance.

  Drake  


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Re: [RE-wrenches] Forklift battery life

2010-10-31 Thread Joel Davidson
William, What is the size of your forklift battery and what is the 24-hour 
self-discharge rate?


- Original Message - 
From: "William Korthof" 

To: 
Sent: Saturday, October 30, 2010 7:52 PM
Subject: Re: [RE-wrenches] RE-wrenches Digest, Vol 3, Issue 600


The batteries in my forklift are from the early 90's and continue to 
perform, despite regular abuse and irregular care. I'll second the comment 
about the economy of golf cart batteries... They are great for situations 
where they can be made to fit.
They've worked well for me in all sorts of applications, and even when 
they actually fail due to abuse or application misfit, the remedy is not 
much of a hardship. But you do need to remember that they are commodity 
traction batteries, not heavy duty solar float or cycling batteries...


/wk



On Oct 30, 2010, at 10:35 AM, re-wrenches-requ...@lists.re-wrenches.org 
wrote:



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Today's Topics:

  1. Re: Are Thick Plate Batteries Worth the Price? (Dave Palumbo)


--

Message: 1
Date: Fri, 29 Oct 2010 22:57:43 -0400
From: "Dave Palumbo" 
To: "'RE-wrenches'" 
Subject: Re: [RE-wrenches] Are Thick Plate Batteries Worth the Price?
Message-ID: <051901cb77de$42a97d00$c7fc77...@com>
Content-Type: text/plain; charset="us-ascii"

All,



I've worked with most battery types in 23 years in the trade. There are 
no

easy answers here. We see the unusual T-105 battery bank go 12 years.
Conversely we have seen people blow through L-16's in 3 years. I 
personally

have some gigantic (Hoppecke LA's 330lbs each cell) 2v cells in my shop
system that are 16 years old and show no signs of decline. They are 
German
made and brought in special to make good on a failed fibered NICAD 
battery
we sold for Hoppecke in the early 90's  (that was not a pleasant 
experience,
I would not do it again, even for a free 20 year+ battery bank as a 
make-up

gift). Also, I wouldn't want to actually buy these large 2v cells.



If you can trust the life cycle, depth of discharge, charts from the
manufacturer and calculate a simple "best value" for the dollar, than 
you've

done your job. Then it's up to a good system sizing design, good metering
and great user care. Our number one rule is "fully charge every ten days 
(at

least)". If you do this, you avoid sulfation, the number one culprit in
early battery demise.

For a small system  the T-105's typically are the best value. In larger
system's there are more choices. A string, or two, of 2v cells can be an
excellent choice depending on the price/value ratio. Medium size systems
will normally call for Surrette/Rolls 6v, or Trojan L-16 batteries. All 
for

off grid applications. Sealed batteries for battery backup grid tied.



Dave Palumbo

Independent Power LLC

Offices in Lamoille and Champlain Valley, Vermont

www.independentpowerllc.com

NABCEP Certified PV Installer

Vermont Solar Partner

802.888.7194









From: re-wrenches-boun...@lists.re-wrenches.org
[mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of jay peltz
Sent: Friday, October 29, 2010 8:52 PM
To: RE-wrenches
Subject: Re: [RE-wrenches] Are Thick Plate Batteries Worth the Price?



HI Nick,



I gotta ask have you ever seen a battery last 25 years that wasn't in 
float

and had to do some work,

or even 15 years?



jay

peltz power

On Oct 29, 2010, at 5:17 PM, Nick Soleil wrote:





You generally pay for what you get.  The industrial 2V cells generally 
cost
more, but will last a lot longer (up to 25 yrs.)  I think it depends on 
the

customer's budget, and the long term plans for the property.



Nick Soleil
Project Manager
Advanced Alternative Energy Solutions, LLC
PO Box 657
Petaluma, CA 94953
Cell: 707-321-2937
Office: 707-789-9537
Fax: 707-769-9037





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[RE-wrenches] Need 12 each 200-watt PV laminates

2010-10-22 Thread Joel Davidson

Wrenches,

I need 12 each 200-watt or higher output PV laminates (no frames). Please 
contact me off-list if you know a source. Thanks in advance.


Best regards,
Joel Davidson

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Re: [RE-wrenches] The perfect solar ready roof

2010-10-22 Thread Joel Davidson
Roof construction knowledge and roofing experience is essential if you are a 
solar designer and installer. You or people you work with must with have roof 
experience. If you do not have an experienced roofer in your organization, then 
you must work closely with an experienced roofing subcontractor (unless you 
like getting angry phone calls when it is raining).

Framing and roofing a standing seam metal roof is not difficult. There is no 
need to guess or to ask inexperienced people what they think should be done. 
Good suppliers will provide specifications, instructions, and drawings and put 
you in touch with experts who can answer your questions.

In 1996, I did the Unisolar standing seam roof at the University of California 
Irvine campus. See http://www.hamcontact.com/unisolar/roofapps.html All we had 
was to start with was a 2nd floor deck and a contract with Southern California 
Edison (SCE) and the DOE UPVG (Utility Photovoltaic Group now called SEPA) who 
cost-shared the 5 kW new roof BIPV system. Unisolar provided standing seam 
metal roofing installation instructions but knew very little about roofing. I 
talked with McElroy, the manufacturer of the roofing Unisolar used for their 
SSR product. I also visited metal roofing jobsites during construction to see 
if anything new had been developed since I last did a metal roof a few years 
before. Then I designed the framing, building attachments, and the PV system 
and got SCE and Campus approval. I was concerned about my attachments to the 
roof deck knee-wall so I asked for the building structural drawings and really 
lucked out. The engineer who had designed the building still worked at his 
nearby office part-time even though he was 85 years old. (This old-timer still 
came to his office in a suit and tie to share his over 50 years of knowledge, 
experience, and wisdom. I love working in the construction industry.) He and I 
spent 15 minutes reviewing my design and he gave it his blessing.

When I designed the solar roof, the University's Combustion Engineering Lab 
Director said that he might want to someday enclose the roof deck so we put in 
metal diagonal straps under the roof panels to brace the roof. The engineer 
said this was a good idea because it strengthened the roof in case of 
earthquakes.

The construction went smoothly. We fastened the ledger and post attachments 
with lag bolts and attached the posts, beams and purlins. The SSR panels were 
laminated at the Unisolar factory and shipped from Troy, Michigan (a waste of 
time and money). When we started fastening the standing seam panels, I had to 
ask the University lab engineers to turn off the experimental natural gas fuel 
cell they were testing on the deck because the rising heat was cooking us on 
the roof like grilled hotdogs. We fastened clips 6 inches from panel ends and 
also every 12 inches using self-taping stainless steel screws (over-kill but it 
went fast). The slowest work was lapping the 12-feet panels over the 18-feet 
panels because each panel's standing seam had to be notched with a sidecutter 
and fit into place. The electrical work was conventional. The homerun in 
conduit went into the building to a Trace SWODE SW5548 that back-feeds to a 120 
VAC breaker in a subpanel.

A few years ago, I was on campus so I dropped by to inspect the system. The 
deck was enclosed and the space turned into offices and the Trace inverter was 
still working like new.

Joel Davidson


- Original Message - 
  From: North Texas Renewable Energy Inc 
  To: RE-wrenches 
  Sent: Friday, October 22, 2010 7:47 AM
  Subject: Re: [RE-wrenches] The perfect solar ready roof


  Phil hits the nail on the head, it sounds like we've both been down this 
road. Problem is it's not always as simple as asking the roofers to do their 
job your way when you are not signing their paycheck.
  I contracted a metal roof PV installation a few years back but only got the 
job on the condition, by the very fastidious homeowner, that I could verify 
that the installation won't cause leaks or void the warranty on the <2 year old 
roof. He gave me the roofers name and the roofing product and mfgr. I 
researched the manufacturers installation requirements for our inland climate. 
Then I called the roofer and asked if the 16" wide panels were installed per 
the mfgrs specs. 
  He proceeded to go ballistic, telling me that if I put one module on 'his' 
roof he would void the warranty. Even after sending him links to the S5 
engineering test results he refused to even talk to me. Finally the customer 
had to have a long talk with the guy before he was convinced his roof had been 
installed correctly. 
  Bottom line you cannot ever be certain about the quality of the installation 
by someone else.  Besides, the homeowners insurance company will have the last 
word on whether a PV mounted roof, found across the street after a windstorm, 
was installed right or

Re: [RE-wrenches] AC voltage in North America

2010-10-19 Thread Joel Davidson
Hello Darryl,

I tip my hat in honor to your many years working with electricity. 110 volts 
was Edison's choice for direct current. Then Tesla/Westinghouse chose higher 
voltage alternating current stepped down to 120 volts. See 
http://en.wikipedia.org/wiki/War_of_Currents 115-volt AC/DC universal motors in 
drills and other tools were fairly common until low-cost induction motors 
became widespread.

Best regards,
Joel Davidson

  - Original Message - 
  From: Darryl Thayer 
  To: RE-wrenches 
  Sent: Monday, October 18, 2010 7:18 PM
  Subject: Re: [RE-wrenches] AC voltage in North America


When I was an electrical apprentus back in the late 40's we called it 
110/220 then in the fifties the voltage was reised to 115/230  and some time in 
the 1960 it was raised to 120 240 

Darryl

--- On Mon, 10/18/10, Marco Mangelsdorf  wrote:


  From: Marco Mangelsdorf 
  Subject: [RE-wrenches] AC voltage in North America
  To: "'RE-wrenches'" 
  Date: Monday, October 18, 2010, 8:27 PM


  I just don’t understand it.



  Lots of people—from reporters to homeowners—consistently refer to the 
AC voltage in their homes as “110/220.”



  Where does this come from?



  If North American utilities were putting out power at that voltage 
range, they would be in serious trouble.



  Anyone able to educate me on this matter?



  marco




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Re: [RE-wrenches] Enphase v. string inverter

2010-10-11 Thread Joel Davidson
Hello Drake,

I have observed hundreds of PV systems in the early morning and can say without 
doubt that string inverters are not inherently slow to wake up.

For example, today my 12 year old SW4048 with a single crystal PV array facing 
south at 12 and 18 degrees tilt and my SB2100 with a single crystal PV array 
facing south at 18 degrees both were putting out power at 7:45 am when the sun 
was 9 degrees above the horizon at azimuth 105 degrees. Today the sky is clear 
and the sun rose in Los Angeles at 6:57 am.

I have seen systems with 100 kW Xantrex inverters and flat Unisolar arrays wake 
up before the morning sun rose above the horizon. Granted the systems were 
putting out less than 5 kW, but the inverters were on.

See you all at the solar conference.

Best regards,
Joel Davidson


- Original Message - 
  From: Drake 
  To: RE-wrenches 
  Sent: Monday, October 11, 2010 6:39 AM
  Subject: Re: [RE-wrenches] Enphase v. string inverter


  I'm now monitoring a 5.376 kW system we recently installed. The sun is barely 
up, with light clouds, and a portion of the array is still in shade.  The 
system is putting out 700 watts.  A string inverter would probably be waiting 
to start. 

  My main problem with the Enphase is the 199 watt limit to its output.  The 
inverters are rated for up to 235 watt modules.  This 224 watt module array 
spends a fair amount of time at full inverter capacity during cool sunny days.  
Maybe these inverters should not be used with over 210 watt modules.  

  Drake 



  At 12:50 AM 10/11/2010, you wrote:

The main advantage of Enphase is the module level monitoring.  However, 
the increased output due to partial shading can be significant.  I was at a 6 
year old PV site this week, and a tree had grown up near the base of the roof.  
Branches were casting a few minor shadows on the array, but was wiping out 75% 
of the production.  I can assure you, those 9 modules would have been producing 
'50+% greater output'
Nick Soleil
Project Manager
Advanced Alternative Energy Solutions, LLC
PO Box 657
Petaluma, CA 94953
Cell: 707-321-2937
Office: 707-789-9537
Fax: 707-769-9037



From: Jamie Johnson 
To: RE-wrenches 
Sent: Sun, October 10, 2010 5:38:55 AM
Subject: Re: [RE-wrenches] Enphase v. string inverter

Marco,

The last I heard the NREL was testing enphase vs. a string inverter, they 
were also suppose to test enphase vs. A competitors module level mpp tracking.  
Not sure if that performance test is complete yet.  

I have seen 1 independent unshaded test ( potentially biased ) which IIRC 
showed enphase ~1% less than a string inverter, this seems to match the 
inverters CEC rating.

What we see around here is an over estimate of kWh production by the 
selling contractor using enphase, sometimes by 50+% greater than unshaded kWh 
estimates.

Performance guarantees with monetary compensation back to the customer if 
estimates are not met can be a good thing and improve the industry IMHO.

Jamie Johnson
General Manager
SOLAR POWER ELECTRIC TM
NABCEP Certified Solar PV Installer #031310-118
(941) 380 - 0098
www.SPEFL.com
Commercial & Residential
FL State Certified # EC13001765

Sent from my iPhone

On Oct 9, 2010, at 7:07 PM, "Marco Mangelsdorf"  wrote:


  Does anyone know of any reports out there from a neutral, 3rd party which 
compares an Enphase array with an array using a string inverter with both 
arrays on the same unshaded surface?

   

  Some Enphase peddlers here are saying that the energy harvest from an 
Enphase system is going to be better since they supposedly come on sooner and 
stay on later in the day.

   

  One guy is actually saying that the Enphase inverters come on before the 
sun comes over the horizon.   Maybe from the same family that claimed that a-Si 
modules produced power from the moonlight.

   

  Thanks,

  marco

   
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Re: [RE-wrenches] UL and Grid-tied Battery Back Up Systems

2010-10-05 Thread Joel Davidson
Hello Peter, It was good to see you at the LADWP Commissioners Meeting even 
though we didn't have time to talk. I told Mr. Benyamin, LADWP AGM, at the 
meeting that there were no safety issues regarding grid-tie PV system with 
batteries because the inverters were IEEE 929 compliant. He said he was 
concerned about batteries being added to a PV system after the initial 
utility inspection. I told him that batteries can not be added to a 
non-battery inverter. He said it is being done so the conversation ended. 
How many people are adding battery inverters later? I've done hundreds of 
grid-tied systems and never added a battery inverter and battery bank after 
the initial installation.


Wrenches, are you adding batteries to non-battery grid-tied PV systems after 
the initial installation? If yes, what inverter and how do you deal with the 
inspector?


Joel Davidson

- Original Message - 
From: "Joel Davidson" 

To: "RE-wrenches" 
Sent: Tuesday, October 05, 2010 7:43 AM
Subject: Re: [RE-wrenches] UL and Grid-tied Battery Back Up Systems



Peter,

California utilities use to require operating steps (list not UL listing) 
for all grid-tied systems in the interconnection application. A copy of 
the operating steps from the equipment manual sufficed.


Joel Davidson

- Original Message - 
From: "Peter Parrish" 

To: "'RE-wrenches'" 
Sent: Tuesday, October 05, 2010 4:05 AM
Subject: [RE-wrenches] UL and Grid-tied Battery Back Up Systems


Are there UL testing procedures for Grid-tied Battery Backup Systems, such
as the Xantrex XW systems and the Outback GVFX systems? The reason for my
inquiry is that the Los Angeles Department of Water and Power intends to
require that "...applicants installing Battery Backups on their solar
systems to submit an Operational Listing detailing a precise list of steps
of what were to happen if the LADWP grid were to lose power."

- Peter


Peter T. Parrish, Ph.D., President
California Solar Engineering, Inc.
820 Cynthia Ave., Los Angeles, CA 90065
CA Lic. 854779, NABCEP Cert. 031806-26
peter.parr...@calsolareng.com
Ph 323-258-8883, Mobile 323-839-6108, Fax 323-258-8885




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Re: [RE-wrenches] UL and Grid-tied Battery Back Up Systems

2010-10-05 Thread Joel Davidson

Peter,

California utilities use to require operating steps (list not UL listing) 
for all grid-tied systems in the interconnection application. A copy of the 
operating steps from the equipment manual sufficed.


Joel Davidson

- Original Message - 
From: "Peter Parrish" 

To: "'RE-wrenches'" 
Sent: Tuesday, October 05, 2010 4:05 AM
Subject: [RE-wrenches] UL and Grid-tied Battery Back Up Systems


Are there UL testing procedures for Grid-tied Battery Backup Systems, such
as the Xantrex XW systems and the Outback GVFX systems? The reason for my
inquiry is that the Los Angeles Department of Water and Power intends to
require that "...applicants installing Battery Backups on their solar
systems to submit an Operational Listing detailing a precise list of steps
of what were to happen if the LADWP grid were to lose power."

- Peter


Peter T. Parrish, Ph.D., President
California Solar Engineering, Inc.
820 Cynthia Ave., Los Angeles, CA 90065
CA Lic. 854779, NABCEP Cert. 031806-26
peter.parr...@calsolareng.com
Ph 323-258-8883, Mobile 323-839-6108, Fax 323-258-8885




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Re: [RE-wrenches] PV and Roof Flammability

2010-09-24 Thread Joel Davidson
On the plus side, roofs under PV arrays receive less ultraviolet radiation. 
On the negative side, some roofing shaded by PV arrays experience mold 
growth.


- Original Message - 
From: "Darryl Thayer" 

To: "RE-wrenches" 
Sent: Thursday, September 23, 2010 6:39 PM
Subject: Re: [RE-wrenches] PV and Roof Flammability



Hi all
Of course there were some fires with thermal collectors where the wood and 
shingles cought fire with inadaquite venting.  No venting was the case.


But I have measured the temperature under PV when it was vented and the 
roof was cooler under the array than elsewhere.




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Re: [RE-wrenches] PV and Roof Flammability

2010-09-24 Thread Joel Davidson

Wrenches,

Building fires are serious stuff. The Northbrook UL labs fire tests are 
awesome. Imagine a gale-force wind driving a wide, roaring natural gas flame 
at the roof eave to see how far the fire will spread as it consumes the 
roofing material and anything else combustible. Tremco has a photo of the 
spread-of-flame test at http://www.tremcoroofing.com/qa/fire_test.asp Some 
roofing material is self-extinguishing. Some roofing material burns to 
ashes. PV module glass does not feed the fire from the top but module 
backsheets combust. Non-glass modules combust readily but can be rated Class 
A in low-pitch applications.


For a photo of the burning brand test see 
http://www.extension.org/pages/Fire_Ratings_for_Roofing_Material Glass solar 
modules on stand-off mounts have saved homes from flying burning brands.


I think that most wrenches warn their customers about fire hazards. Stay 
safe.


Joel Davidson

- Original Message - 
From: "Matt Lafferty" 

To: "'RE-wrenches'" 
Sent: Thursday, September 23, 2010 6:22 PM
Subject: Re: [RE-wrenches] PV and Roof Flammability



Wrenches,

I'm coming from a perspective of comparing "beneath array" areas to "not
beneath array" areas of the same roof. Regarding flammability, I don't
really care what the source of ignition is in this conversation. I prefer 
to

think that the PV isn't the cause, frankly. Would rather think in terms of
flying embers from a fire in the area (wild fire, neighbor's house on 
fire,

chimney, etc.), but I don't think we can discount any cause out of hand.

I think it is very important to understand that the UL tests are designed 
to

emulate pre and early-stage combustion, as opposed to emulating a
fully-involved fire situation. This is important because it marks the
difference between "fire resistant" and "fire proof" materials. Only fire
proof materials would survive to pass a full-on fire test. These tests
essentially test the fire resistance of roofing materials.

Another element to understand is that these tests only test from the top.
They don't emulate an attic-fire burning thru the sheathing and engulfing
the roofing materials from the back.

Based on observation and farm boy commons, it seems to me that the biggest
problem area is low-profile, flush mounted arrays over petroleum-based
roofing materials. These are parallel to and close to the roof surface. 
Most

commonly with horizontal rails below the surface of the modules, thereby
reducing the effective clearance to the roof by the height of the rail.
Which dramatically reduces convection. This mounting configuration
concentrates heat onto the roof surface and traps roof gasses beneath the
array from otherwise normal ventilation.

Gassing is normal and occurs throughout the life of most roofing 
materials.
Petroleum based roofing products tend to gas at a declining rate 
throughout

their life cycle. This gassing is not generally combustible in these
concentrations. Combustible gasses are created when a roofing material
begins to burn. Early-stage combustion. If these combustible gasses are 
not

allowed to evacuate quickly, the fire is exacerbated Gaining heat and
intensity quickly. Flame spread.

Once the roofing material is fully involved, meaning self-sustained 
burning,

it's probably not gonna matter much whether there is an array above it or
not unless someone is there to fight the fire.

The "chimney" effect behind a tilted array would have three primary 
effects
on this cycle. The first effect is that normal gassing would occur 
similarly

to adjacent roof sections not covered by the array. The second is that,
during pre and early-stage combustion, the combustible gasses will not
concentrate between the module and the roof, effectively reducing the fuel
and heat concentration by some amount. Possibly to a level that is equal 
to
adjacent roof sections not covered by the array. Possibly even 
extinguishing

an ember or small flame in a manner similar to blowing on a lit match. The
third effect would occur once the roofing material is fully involved. In
this part of the cycle, the chimney effect could certainly draw more air
into the fire, possibly increasing its intensity, much like blowing into 
the

base of a campfire.

From a pure flammability perspective, I like the tilted array better than
the flush array. My reasoning is primarily that normal aging will be more
likely and, if an ember were to reach the roof beneath the module, it is
more likely to self-extinguish or at least act like the adjacent roof. 
These

characteristics reduce the overall liklihood of actually catching fire in
the first place. Which I like.

In the event that the roof beneath a tilted array were to become involved
and induce an adverse chimney effect, the fire would be WAY more 
accessible

to a water hose than with a flush mounted array.

Another negati

Re: [RE-wrenches] PV and Roof Flammability

2010-09-23 Thread Joel Davidson

Hello Bill,

Thanks for the feedback. I need to learn more about this issue. I plan to 
attend the October 15th SolarABC meeting after the LA conference. Is 2012 
IBC draft available?


How can PV systems be classified, let alone fire-rated, when there is a 
seemingly infinite combination of module, mount, wiring, inverter, and 
safety devices possible?


Will system classification require system certification like Florida?

Is the air gap considered a problem only for tilted PV arrays? The reasons I 
ask are (1) because stand-off arrays parallel to low-pitched roof are 
mounted like HVAC equipment and (2) HVAC and other roof-mounted equipment do 
not change the building's occupancy group, construction type and minimum 
roof class.


Best regards,
Joel Davidson

- Original Message - 
From: "Bill Brooks" 

To: "'RE-wrenches'" 
Sent: Thursday, September 23, 2010 8:29 AM
Subject: Re: [RE-wrenches] PV and Roof Flammability



Joel,

The problem is not with the rating of the modules. It is with the way we
install them. The air gap is a problem. If HVAC systems were installed 
like
PV modules, they would have the same problem. There will be changes of 
some

sort coming in the next year or so. The IBC in 2012 will require "PV
systems" to have a fire rating. Module fire rating may become irrelevant.
Time will tell. This is in a very preliminary stage. All we know is that
changes are likely with this new IBC language.

There is a group working on this issue that includes several 
representatives
from the PV manufacturing and PV installing industries. If this is 
something
you want to put a lot of personal effort into, there are ways to 
accommodate

good input. The SolarABCs will be helping coordinate ongoing efforts.

Bill.

-Original Message-
From: re-wrenches-boun...@lists.re-wrenches.org
[mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Joel
Davidson
Sent: Wednesday, September 22, 2010 7:12 PM
To: RE-wrenches
Subject: [RE-wrenches] PV and Roof Flammability

Wrenches,

See http://www.solarabcs.org/flammability/ and the report at
http://www.solarabcs.org/flammability/Flammability_Interimreport.pdf

Is there any flammability difference between PV equipment on a roof and 
HVAC


or air handling equipment on a roof? My concern is whether PV is being
singled out as a flammability concern while other more established
industries with more powerful lobbyists are not.

Joel Davidson

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[RE-wrenches] PV and Roof Flammability

2010-09-22 Thread Joel Davidson

Wrenches,

See http://www.solarabcs.org/flammability/ and the report at 
http://www.solarabcs.org/flammability/Flammability_Interimreport.pdf


Is there any flammability difference between PV equipment on a roof and HVAC 
or air handling equipment on a roof? My concern is whether PV is being 
singled out as a flammability concern while other more established 
industries with more powerful lobbyists are not.


Joel Davidson 


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Re: [RE-wrenches] Delta LAs

2010-09-17 Thread Joel Davidson
Wrenches,

Allan Sindelar's 2003 RE-Wrenches lightning discussion compilation was a 
keeper. Email me off-list for a copy. (Thank you Allan).

Joel Davidson
  - Original Message - 
  From: August Goers 
  To: RE-wrenches 
  Sent: Tuesday, September 14, 2010 6:00 PM
  Subject: Re: [RE-wrenches] Delta LAs


  Jay - 

  I can see that point, but does that really effect insurance payout? It seems 
like one could argue that a properly installed system with proper grounding 
inspected by a building official has a lot more clout than and little grey 
cylinder next to the inverter or disconnect.

  Please all wrenches, correct me if I'm wrong but I can't remember a single 
time when there was a post about an actual lightning strike and a lightning 
arrestor actually doing its job - meaning that an arrestor took a hit and 
protected the array and or inverter. I've heard plenty of stories about blown 
lightning arrestors and good equipment but no one seems to know what caused the 
situation. It might be that lightning is hard to track and I agree with that. 
And lightning might have been the cause. It would be great to track 
lightning-fried installations to see what happened and what could be fixed. If 
lightning arrestors are the solution then by all means we should install them. 
Most of the time I think that proper grounding is the solution although I wish 
that field experience would prove the point. 

  What do you think?

  -A


  On Tue, Sep 14, 2010 at 5:28 PM, jay peltz  wrote:

I also live in a area without much lightning, however I install one in most 
systems for the simple reason of insurance.
If there is lightning damage, the insurance company can't use that as a way 
to not pay any claims.
ie cheap insurance.

jay

peltz power

On Sep 14, 2010, at 8:39 AM, August Goers wrote:

> All -
>
> I guess my thought is a little off topic, but are lightning arrestors 
even worth using at all? My logic has always been that if lightning does indeed 
strike that it's likely going to blow the arrestor and and inverter. We don't 
have much of a lightning issue issue in the Bay Area so I don't have any direct 
experience.
>
> Best,
>
> August
>


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  -- 
  August Goers
  VP, Engineering

  Luminalt Energy Corporation
  1320 Potrero Avenue
  San Francisco, CA 94110
  O: 415.641.4000
  M: 415.559.1525
  aug...@luminalt.com



--


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Re: [RE-wrenches] Delta LAs

2010-09-14 Thread Joel Davidson
CE is a self-certification that requires no 3rd party testing. In other words, 
if you think your product meets a standard and take the time to write a letter 
stating such, then you are CE certified. There are companies who you can pay to 
give you the letter, but it is easy to go on-line, learn the CE mark 
requirements and DIY.





From: Mick Abraham 
To: RE-wrenches 
Sent: Tue, September 14, 2010 12:17:34 PM
Subject: Re: [RE-wrenches] Delta LAs

Citel products do have a listing mark but this is European style CE, not 
American style UL/ETL. Citel is reputedly working on American certification but 
one would be advised to not hold one's breath.  


The Citel products which mount to a DIN rail have an LED indicator which goes 
dark once the surge elements have been sacrificed. Also some of their units 
have 
an auxiliary switch which can remotely indicate a blown condition. This is in 
the form of dry contacts..a normally open and a normally closed one, so various 
indicator circuits can be designed around that. The contacts have a low amp AC 
rating and also a (lower amp) DC rating but I do not remember the numbers at 
present. 

Jolliness,

Mick Abraham, Proprietor
www.abrahamsolar.com

Voice: 970-731-4675



On Tue, Sep 14, 2010 at 12:43 PM, R Ray Walters  wrote:

You could buy several ground rods for the cost of one Delta. 
>Ground Impedance is the real issue. Both the Delta and the Polyphasor need a 
>good ground to work. 
>
>While I haven't seen much of a correlation between Deltas and reduced 
>lightning 
>damage, (lots of system damage with and without)
>I have found that well grounded systems (tied to a steel cased well) have 
>never 
>had a problem, even with direct strikes to a wind turbine (did lose the $40 
>turbine rectifier, but nothing else)
>
>
>I now own a clamp-on ground impedance tester, and the results were miserable. 
>Some electrodes were over 800 ohms to ground! (code requires under 25 ohms)
>I'd spend more time and money reducing ground impedance, and then if it makes 
>you feel good inside, throw the little "lightning faeries" in, if the AHJ 
>isn't 
>looking...
>
>
>If its really lightning country, and a really expensive off grid system, I use 
>Polyphasor, but they have their own issues. (very expensive, no UL listing, 
>loose internal connections, nuisance tripping, need a large J-box to mount 
>them 
>inside, etc.)
>I haven't tried the Citel stuff, but it looks to be listed, and mounts on a 
>DIN 
>rail. After installing a couple hundred Deltas, I'd try something else at this 
>point.
>
>
>
>
>R. Walters
>r...@solarray.com
>Solar Engineer
>
>
>
>
>
>
>
>On Sep 14, 2010, at 10:22 AM, Kristopher Schmid wrote:
>
>My thought here is that nothing will protect the equipment from a direct 
>strike, 
>but a near strike that may induce a significant surge may be absorbed by the 
>LA 
>and protect the equipment.  I like the feedback so far.  It would not break my 
>heart to stop using them altogether.:-}
>> 
>>Kris
>>Legacy Solar
>>864 Clam Falls Trail
>>Frederic, WI 54837
>>715-653-4295
>>sol...@legacysolar.com
>>www.legacysolar.com 
>>-Original Message-
>>>From: re-wrenches-boun...@lists.re-wrenches.org 
>>>[mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of August Goers
>>>Sent: Tuesday, September 14, 2010 10:39 AM
>>>To: RE-wrenches
>>>Subject: Re: [RE-wrenches] Delta LAs
>>>
>>>
>>>All -
>>>
>>>I guess my thought is a little off topic, but are lightning arrestors even 
>>>worth 
>>>using at all? My logic has always been that if lightning does indeed strike 
>>>that 
>>>it's likely going to blow the arrestor and and inverter. We don't have much 
>>>of a 
>>>lightning issue issue in the Bay Area so I don't have any direct experience.
>>>
>>>Best,
>>>
>>>August
>>>
>>>
>>>On Tue, Sep 14, 2010 at 6:29 AM, Kristopher Schmid  
>>>wrote:
>>>
>>>It is quite ironic that just a week after I posted a question to the group
on testing the integrity of lightning arrestors, I had one apparently faulty
out of the box.  The manifest of this was interesting: when the AC LA
(LA302R) was connected in parallel on the AC input to a SB3000 inverter,
there was 125vac neutral to L1, 125vac neutral to L2, and 1Vac L1 to L2.
SMA tech support suggested the LA as the issue and sure enough, it was.
Attempting to test good and faulty arrestors with an ohmmeter gave the same
result - off scale open.

Any thoughts or comments from the group?

Kris Schmid

Legacy Solar
864 Clam Falls Trail
Frederic, WI 54837
715-653-4295
sol...@legacysolar.com
www.legacysolar.com

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[RE-wrenches] Module Ground (was The Demise of Reason)

2010-09-13 Thread Joel Davidson
Bill,

You and John Wiles have shown leadership on the module grounding issue. It 
would 
be good to know who at UL is preventing a universal solution so that this issue 
can be resolved at the highest level once and for all. What do you suggest for 
the course of action?

Joel Davidson





From: Bill Brooks 
To: RE-wrenches 
Cc: Christopher Flueckiger ; Tim Zgonena 

Sent: Mon, September 13, 2010 8:44:39 AM
Subject: Re: [RE-wrenches] The Demise of Reason

Peter,

No tone was intended. The theme of your post was good, but the subject was
misleading. The fact that you were shocked twice by my questioning your
subject means that you misunderstood the tone of my questioning of your
subject title. I misunderstood your post and reacted to a very negative
subject heading that gave the impression that the WEEB product was generally
experiencing its demise. 

I have heard of a few companies that have withdrawn information about the
WEEB in their literature, but I was unaware that SunPower was one of them. 

Grounding of module frames has been a big issue for over a decade and module
manufacturers have not done a lot to help the installer in this area. When
UL cracked down on the haphazard way that grounding was being approached in
the field, it became a major issue. Manufacturers had to retest many of
their products and provide details on the methods allowed in their manuals.
Since adding grounding options to a module required additional testing which
was expensive, many manufacturers went the easiest route to get approved.
This was not good for products like the WEEB since it now required testing
with every module type. In addition, my understanding is that UL has not
allowed the WEEB on UL-listed products since the product was not evaluated
by UL and they do not have the test data that supports how it was evaluated.
That may be the source of the issue with SunPower--you would have to ask
them directly.

We need a more generic approach to grounding and that is what is currently
underway. Grounding and bonding is extremely important and jurisdictions are
focused on it for obvious safety reasons. We need solutions that are clearly
reliable and straightforward so that installers and jurisdictional
authorities don't have to constantly be revisiting the issue.

Bill.


-Original Message-
From: re-wrenches-boun...@lists.re-wrenches.org
[mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Peter
Parrish
Sent: Monday, September 13, 2010 7:18 AM
To: 'RE-wrenches'
Cc: 'Christopher Flueckiger'; 'Tim Zgonena'
Subject: Re: [RE-wrenches] The Demise of Reason

Bill (and Chris and Tim),

"Be a little bit more careful in your choice of subjects..."?

I am shocked, shocked that you would use that tone with me. 

If you would re-read my post, I talked about three things: 

(1) SunPower's no longer supporting the WEEB clip technology and regressing
to the ILSCO GBL-4DBT. 

You are right about the insertion of the star washer between the lug and
module frame. I wonder what SP's response to that might be...

(2) As for SP's comment that they pulled the WEEB clip, "due to UL testing
changes". Does anyone close enough to the situation know what this means?

(3) I never mentioned the SP IFF clip. I mentioned the Tyco SolKlip. 

SP mentions the IFF in their literature but do not offer it to their dealers
(as far as I know), and I haven't been able to find it yet in their product
literature, except for a small low-resolution image. I assumed that the Tyco
SolKlip was a different component -- however it may be similar or may be
rebranded by SP as the IFF -- I don't know.

Bonding PV arrays and their supporting structures is complicated subject and
in my experience is one of the more frequently examined aspects of PV
installations by inspectors (along with bonding and grounding the other
components). So it would seem to be an apt subject for discussion by those
of us actively installing PV systems subject to inspection by the AHJ.

- Peter 
                                                    
Peter T. Parrish, Ph.D., President
California Solar Engineering, Inc.
820 Cynthia Ave., Los Angeles, CA 90065
CA Lic. 854779, NABCEP Cert. 031806-26
peter.parr...@calsolareng.com  
Ph 323-258-8883, Mobile 323-839-6108, Fax 323-258-8885


-Original Message-
From: re-wrenches-boun...@lists.re-wrenches.org
[mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Bill Brooks
Sent: Sunday, September 12, 2010 8:50 PM
To: 'RE-wrenches'
Cc: 'Christopher Flueckiger'; Tim Zgonena
Subject: Re: [RE-wrenches] The Demise of Reason

Peter,

Be a little more careful in your choice of subjects. You are talking about
the SunPower IFF clip. I have not heard this story, but I don't doubt it.
There have been significant changes at UL and ETL, the two largest listers
of PV modules, in the area of evalu

[RE-wrenches] PV Monitoring - German Style

2010-09-06 Thread Joel Davidson
From SMA's website monitoring over 27,000 PV systems. By "all PV plants in 
Germany" I assume they mean all plants with SMA monitoring. See 
http://www.sma.de/en/news-information/pv-electricity-produced-in-germany.html


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Re: [RE-wrenches] Micro-Inverter Challenge Winners Declared.Interesting details to follow.

2010-09-05 Thread Joel Davidson

Hello Ryan,

I wonder if SMA still thinks their 569 Sunny Boy system at the Mont-Cenis 
Academy is a good design? See 
http://www.google.com/imgres?imgurl=http://www.sma.de/uploads/tx_templavoila/SB04_04.jpg&imgrefurl=http://www.sma.de/en/products/references/solar-inverters.html&usg=__z_925mXuLKvJFrs9XG6_snB1bHE=&h=156&w=222&sz=58&hl=en&start=3&zoom=1&itbs=1&tbnid=dZezHYAqkkXV5M:&tbnh=75&tbnw=107&prev=/images%3Fq%3Dphotovoltaic%2BAcademy%2BMont-Cenis%26hl%3Den%26gbv%3D2%26tbs%3Disch:1


Joel Davidson


- Original Message - 
From: "Ryan J LeBlanc" 

To: 
Sent: Sunday, September 05, 2010 6:33 AM
Subject: [RE-wrenches] Micro-Inverter Challenge Winners Declared.Interesting 
details to follow.




Hello all,

Jay Ruzicka of Occidental Power (CA) was the first to submit a design that 
I

could not find a reasonable solution that would work as smartly with
available string inverters as they would with a micro-inverter design.
Allan Sindelar of Positive Energy (NM), gets a runner up win, for a value
equaling a case of good stout.  Having been in the large commercial space
for a while, it was nice of these guys to submit designs and have the
discussions.

My guess would've been that folks were going to be submitting a typical 
3kW

residential system design with multiple planes, or shading issues, and
arguments of MPPT, or reliability, or that putting a bunch of inverters
behind the modules would be fine because "they" said it was ok, but what I
found was definite lack of efficient, cec listed, small power inverters 
for

these sub 2kw, and sub 1kw systems, and designers just have a lack of
options in this smaller territory.

Good lesson to String Inverter Manufacturers to continue to develop higher
efficiency single string inverters to compete, meanwhile some seem to be
bailing from this space, regarding smaller listed inverters and lower 
input

voltages.  There are literally no sub-1000's or 1100's listed with
competitive efficiencies.  Kaco has the 1500 at 95.5% the same as 
Enphase's

best number.  After that, there's a few other 1500's and 2000's that post
95%, 94.5% and worse.

For projects in this system size territory, that is sub-2kw, where one 
could

reason that only a few inverters behind the modules may be ok, there is a
lack of alternatives.  So, some of the things that would be good for 
string
inverter manufacturers to work on to combat the micro-inverter craze, 
seems

to be continuing in the race to bring up the efficiency of smaller units,
perhaps working on multiple MPPT units, perhaps with power stages like the
larger fronius units but at lower or wider voltage ranges and smaller 
power

ratings, perhaps offering units with lower input voltage windows to
accommodate shorter strings, integrating better/cheaper monitoring, or
letting more people know about their existing monitoring solutions, 
keeping

cost down, and getting them listed and approved soon.

In a podcast recently @
http://www.renewableenergyworld.com/rea/news/podcast/2010/02/micro-inverters
-vs-central-inverters-is-there-a-clear-winner, Raghu said that a couple
hundred thousand units have been sold since 08, for the sake of discussion
let's say they're 200W each and $1/Watt.  That's 200,000 (x) 200 (x) $1 =
$40 Million in sales...  Guess I should listen to the podcast again to 
make

sure he said that many, but if so, that's quite a chunk of change these
other guys should be working for.  If micro-inverter efficiency were to 
hold

up, and installation speed could be dramatically increased, a string
inverter that would compete will have to be able to accommodate shorter
strings, at better efficiencies.

Obviously, not ground breaking work, we've all already known that sub 2kw
systems were viable candidates for micro-, but I was very disappointed to
see such a lack of competition on the CEC list for those of us looking to
keep our inverters out from underneath the array.

Ryan

**

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Re: [RE-wrenches] Inverter for fire protection pump

2010-08-28 Thread Joel Davidson

Wrenches,

This group's experience, collective wisdom, and willingness to share 
practical knowledge and interesting ideas are how I envision higher 
education in the future. Thank you all for your helpful information. I'll 
report back what the customer decides to do.


Joel Davidson

- Original Message - 
From: "Darryl Thayer" 

To: "RE-wrenches" 
Sent: Saturday, August 28, 2010 8:24 AM
Subject: Re: [RE-wrenches] Inverter for fire protection pump


Sorry this could be more helpful if I had a better memory, I don't mean to 
ramble, but some wrenches may find value.


I am working on a standalone system now and I am in testing.  Normally I use 
OUtback, (and I am very happy)  and this time I decided to use Magnum 4024 
AE.  The job has both a large motor and is AC coupled to DGI inverter.  The 
large motor draws over 120 amp (120 volt) surge when connected to a grid 
source.  I have started this motor in test repeatedly My Greenlee amp clamp 
says it is surging at 90 amps! The VOM says the min voltage is 97 volts. 
This is on ONE 4024 AE,  Magnum is getting close to release of the paralled 
version The test battery set is Trojan T105 single string, and the surge DC 
measured by Ideal DC clamp on is 280 amps.  Voltage and minimum battery 
voltage is 21 volts Ideal VOM.  I would think that the parrellel version 
could handle your motor.


Old system
I did a fire pump install in a large residence, I think back in 2004?  the 
specs were similar except the starting surge was higher and the running was 
almost the same (maximum of 20 amps and less depending upon flow).  I used 
an Odd number of OUtback inverters (5) but not all were to this task.  First 
the starting surge measured by my greenlee clamp-on amp meter was higher on 
the grid than it is on the inverters.  I did a lot of field tests, however I 
do not know where I put the data.  I noticed that if I had fully charged 
batteries the starting was 100% reliable but on batteries at near 50% SoC 
the system started to fault on "low AC" during start-up The batteries were 
L-16 Surrette 48 volt string. If the system was started every five minutes 
it would fault, but if a longer waiting period  I remember during the course 
of the job I started the pump over 100 times in test mode with out a 
failure.  (this system gets annual tests and no problems so far)


Pumps:  We found that the pump current draw depended upon the flow rate we 
allowed..  If we had one head open, the current draw was less than all heads 
open.  The maximum curent draw was at some flow rate in the middle flow 
range! The starting surge was independent of whether the valve was open or 
closed.  If it would be possible to use a SQflex this would be a good 
choise.  Finally this system is grid tied and has a relay to Outback if the 
Grid should fail and it has a generator inlet box if a generator is avaiable 
to take the load.


--- On Fri, 8/27/10, Joel Davidson  wrote:


From: Joel Davidson 
Subject: Re: [RE-wrenches] Inverter for fire protection pump
To: "RE-wrenches" 
Date: Friday, August 27, 2010, 9:50 PM
Hi Ray,

Thank you for your input. The pump is part of a fire
protection system that sucks water out of the swimming pool
and pumps it to roof sprinklers with fire retardant added to
the water. I'll forward your email to my colleague who has
the details.

Best regards,
Joel Davidson

- Original Message - From: "R Ray Walters" 
To: "RE-wrenches" 
Sent: Friday, August 27, 2010 7:23 PM
Subject: Re: [RE-wrenches] Inverter for fire protection
pump


> Forgot to mention the usual info: look at the pump to
see if a smaller or no surge Grundfos SQE might be able to
handle the flow rate and pressure needed.
> Pumps are cheap, when you're considering multiple
inverters..
> Given what you mentioned (110 amp surge at 240 vac), I
don't think even a quad stack of Outbacks could do it. (
please ignore my earlier post)
> A quad stack could run that, just not start it.
Franklin makes a soft start controller, that might work with
that pump. What is the Horse power rating?
>
> R. Walters
> r...@solarray.com
> Solar Engineer
>
>
>
>
> On Aug 27, 2010, at 3:52 PM, R Ray Walters wrote:
>
>> Little beyond a pair of Outbacks, possibly a
pair of Magnasine inverters, or a quad stack of Outbacks.
>>
>> R. Walters
>> r...@solarray.com
>> Solar Engineer
>>
>>
>>
>>
>> On Aug 26, 2010, at 2:41 PM, Joel Davidson wrote:
>>
>>> Wrenches,
>>> Our customer has a fire protection pumping
system that operates at 240VAC and 22 amps with a 110 amps
starting surge. The pump will only be used for up to 4 hours
in an emergency (but hopefully never). The customer wants an
inverter and battery (no generator or PV) in case grid power
is destroyed by fire. What inverter(s) do you recommend?

Re: [RE-wrenches] Inverter for fire protection pump

2010-08-28 Thread Joel Davidson

Hi Ray,

Thank you for your input. The pump is part of a fire protection system that 
sucks water out of the swimming pool and pumps it to roof sprinklers with 
fire retardant added to the water. I'll forward your email to my colleague 
who has the details.


Best regards,
Joel Davidson

- Original Message - 
From: "R Ray Walters" 

To: "RE-wrenches" 
Sent: Friday, August 27, 2010 7:23 PM
Subject: Re: [RE-wrenches] Inverter for fire protection pump


Forgot to mention the usual info: look at the pump to see if a smaller or 
no surge Grundfos SQE might be able to handle the flow rate and pressure 
needed.

Pumps are cheap, when you're considering multiple inverters..
Given what you mentioned (110 amp surge at 240 vac), I don't think even a 
quad stack of Outbacks could do it. ( please ignore my earlier post)
A quad stack could run that, just not start it. Franklin makes a soft 
start controller, that might work with that pump. What is the Horse power 
rating?


R. Walters
r...@solarray.com
Solar Engineer




On Aug 27, 2010, at 3:52 PM, R Ray Walters wrote:

Little beyond  a pair of Outbacks, possibly a pair of Magnasine 
inverters, or a quad stack of Outbacks.


R. Walters
r...@solarray.com
Solar Engineer




On Aug 26, 2010, at 2:41 PM, Joel Davidson wrote:


Wrenches,
Our customer has a fire protection pumping system that operates at 
240VAC and 22 amps with a 110 amps starting surge. The pump will only be 
used for up to 4 hours in an emergency (but hopefully never). The 
customer wants an inverter and battery (no generator or PV) in case grid 
power is destroyed by fire. What inverter(s) do you recommend? Thank you 
very much for sharing your off-grid knowledge.

Joel Davidson

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Re: [RE-wrenches] Tight roof layout questions: edge walkway requirements & "small gap" hardware options

2010-08-27 Thread Joel Davidson
This May 2010 UL/NFPA report "Fire Fighter Safety and Emergency Response for 
Solar Power Systems" shows  eave-to-ridge solar arrays and has a lot of good 
information for designers. See 
http://www.nfpa.org/assets/files/PDF/Research/FFTacticsSolarPower.pdf

  - Original Message - 
  From: Mick Abraham 
  To: RE-wrenches 
  Sent: Thursday, August 26, 2010 5:53 PM
  Subject: Re: [RE-wrenches] Tight roof layout questions: edge walkway 
requirements & "small gap" hardware options


  The Wrench List participants have again responded with aplomb. Thanks to all 
for the dozen or so replies. My takeaway from this is that I need to send my 
roof layouts to the nearby fire department...it's another "authority having 
jurisdiction" situation.


  I received the below mail "off list" from a fire captain in San Jose. He 
cannot post to the List so he asked me to post on his behalf. Moderator Michael 
approved, so Matt Paiss' remarks are copied below. 


  Jolliness,  
  Mick Abraham, Proprietor 
  www.abrahamsolar.com
  Voice: 970-731-4675


Mick,
I wanted to reply to your post.  As a firefighter, and an instructor of PV 
safety for the fire service like Dan Fink, I would like to take a moment to 
expand on what Dan was eluding to.  Firefighters will not always look at an 
edge-to-edge array and decide to "Let it burn" just based on the array size.  
We will take into account the size of the fire, the involvement of the actual 
structural members, and the potential life risk within the structure before any 
tactical strategy is implemented.  I have written off buildings just based on 
wind, or available water supply.
What a setback (the term being used for walkways) allows is primarily for 
access to a roof, or rapid egress off a roof when the fire gets out of control, 
not necessarily for cutting a hole.  I teach firefighters to vent on the other 
side of the ridge from the array.  There is no time to remove modules, and 
while micro-inverters definitely address the safety issues of a 600vdc string, 
they do not address access or egress.  I am not going to recommend that ANY 
firefighter tear off a module to vent a roof because he "thinks" a 
micro-inverter is present.
I realize that these new codes are more restrictive, but even wind load 
zones recommend against edge-to-edge installs.  There will be some latitude in 
the fire codes for setbacks,  so I recommend building a good relationship with 
your local AHJ's.  One way of doing this is by demonstrating safe, high quality 
installs.  I have seen too many wire-ties holding up PV wire that will be 
rubbing against comp shingles for a decade.  How confident are you that that 
will not be a problem?
Regards,
Matt Paiss
Matthew Paiss, Fire Captain
San Jose Fire Department
170 W. San Carlos St.
San Jose, CA 95113
(831) 566-3057 cell


  On Thu, Aug 26, 2010 at 12:45 AM, Philip Boutelle  
wrote:

Just to clarify what is and isn't law in California: 
the final draft guidelines developed and adopted by Cal Fire are 
guidelines, not law, unless the local fire/AHJ has adopted them or parts of 
them into local ordinances. I have heard that in Southern Cal, those guidelines 
have been adopted all over the place already, but not so in the rest of the 
state yet. I think the guideline was officially incorporated into the next 
NEC/NFPA cycle, so it will be law pretty soon. Bill Brooks could probably 
confirm here on future adoption.
Not that any of this helps your Atlanta install


-Phil Boutelle
Real Goods Solar  


On Wed, Aug 25, 2010 at 12:38 PM, Max Balchowsky  wrote:

  Mick, here in California the fire department in the various agencies has 
the final say on clearances. There is a very clear cut standard in place for 
the state, but we have been successful a few times in getting allowances to 
vary due to various site conditions. A call to the local AHJ is the place to 
start. In the early days of our installations (mid 1990's) we used power strut 
and bolted panels directly to the rails. A lot slower but no gaps between 
panels. We went from there to designing our own "T" clamps. There wasn't as 
many choices then for mounting hardware. 


  Max Balchowsky
  Design Engineer
  SEE Systems
  1048 Irvine Ave Suite 217
  Newport Beach, Ca. 92660
  760-403-6810





--
  From: Brian Teitelbaum 
  To: RE-wrenches 
  Sent: Wed, August 25, 2010 11:40:04 AM
  Subject: Re: [RE-wrenches] Tight roof layout questions: edge walkway 
requirements & "small gap" hardware options



  Hi Mick,



  To answer part of your post, the DPW Power Rail mid-clamps give you a 
3/8” gap between modules, and the SnapNrack mids give you a 1/2"  gap.



  I doubt if that will give you much of a walkway though….



  Brian Teitelbaum

  AEE Solar





  From: re-wrenches-boun...@l

[RE-wrenches] Inverter for fire protection pump

2010-08-27 Thread Joel Davidson

Wrenches,
Our customer has a fire protection pumping system that operates at 240VAC 
and 22 amps with a 110 amps starting surge. The pump will only be used for 
up to 4 hours in an emergency (but hopefully never). The customer wants an 
inverter and battery (no generator or PV) in case grid power is destroyed by 
fire. What inverter(s) do you recommend? Thank you very much for sharing 
your off-grid knowledge.

Joel Davidson

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[RE-wrenches] Solar License Database

2010-08-25 Thread Joel Davidson
The Interstate Renewable Energy Council (IREC) created a Solar Licensing 
Database as a resource for policy makers, practitioners, consumers, and 
anyone else looking for solar licensing information in the U.S.  The 
state-by-state information offers a handy comparison for reviewing the 
different approaches across state lines, and identifies various practices 
for regulating the solar installation industry.


In the database, licensing requirements for installing photovoltaic and 
solar thermal systems are documented for each state. Today, only 14 states 
have established specific solar license classifications, usually 
sub-classifications of electrical or plumbing licenses, and often 
specifically defined to limit the scope of work to direct solar 
installations and maintenance tasks.


See http://irecusa.org/2010/08/solar-licensing-information/



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[RE-wrenches] Power Loss from Dust on PV Modules

2010-08-23 Thread Joel Davidson

Wrenches,

A recent news story about "Self-cleaning technology from Mars can keep 
terrestrial solar panels dust free" at 
http://www.ecnmag.com/News/2010/08/Self-cleaning-technology-from-Mars-can-keep-terrestrial-solar-panels-dust-free/
said "A dust layer of one-seventh of an ounce per square yard decreases 
solar power conversion by 40 percent," Mazumder explains. "In Arizona, dust 
is deposited each month at about 4 times that amount. Deposition rates are 
even higher in the Middle East, Australia, and India."


I have measured up to 15% power from a few months Los Angeles summer time 
dust and dirt and much higher loss at a very dirty location in Long Beach. I 
dry wipe small arrays clean and water hose (no wiping) up to 10 kW 
residential arrays. Is anyone experiencing 40% power loss from dust? How are 
you removing dust and dirt?


Thank you for your feedback.

Joel Davidson 


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Re: [RE-wrenches] Prism Solar (was) The Genie Lens

2010-08-15 Thread Joel Davidson
Hello Mick,

Thank you for your kind words. Perpetual motion has been co-opted by the 
lunatic fringe so now I tell people that PV is the most reliable electric 
generator in the known universe.

Working in the PV industry has given me the opportunity to hang out with some 
really wonderful people and Rick Lewandowski is among the best.

Regarding PV reliability, I had the opportunity to hear industry champions 
(like Chuck Whitaker) at the 2006 "Accelerated Aging Testing in Photovoltaics" 
conference. For a summary go to 
http://www1.eere.energy.gov/solar/pdfs/pv_accelerated_aging_summary.pdf

I share your frustration about PV's marginal profitability, but the industry is 
not to blame for the "race to the bottom." Like nuclear power people, PV people 
have been promising clean, reliable, low-cost electricity. Unlike nuclear 
power, PV had no weapons industry to prop it up with billions of dollars of 
subsidies for decades. Instead, PV got a few hundred million for space cells 
R&D and then was turned out by the Reagan administration to fend for itself in 
the marketplace. 50 years later, the nuclear power industry is still getting 
billions every year, but the end-game is near and PV is winning. See 
http://www.ncwarn.org/wp-content/uploads/2010/07/NCW-SolarReport_final1.pdf

Joel Davidson

  - Original Message - 
  From: Mick Abraham 
  To: RE-wrenches ; re-mark...@lists.re-wrenches.org 
  Sent: Sunday, August 15, 2010 4:23 PM
  Subject: Re: [RE-wrenches] Prism Solar (was) The Genie Lens


  Ever since buying an early edition of the Davidson/Komp book in the 80's, I 
knew that Joel D. had a genuine love for PV technology plus a prominent 
position in the industry. 


  Joel would not recall a brief phone conversation that I had with him in that 
era, in which he stated that "a PV module is the closest thing we have to 
perpetual motion". That observation...and the infectious enthusiasm behind 
it...made a lasting impression on me.  


  It's nice to be able to virtually "hang out" with Joel and other industry 
pioneers. 


  *


  The Prism Solar technology (to which Joel points) seems to ring the 
appropriate notes:


  * Similar size per rated watt compared to crystalline


  * Lower production cost per rated watt


  * Projections of higher kWh delivery per rated watt over time


  * Technology that doesn't claim to be magical but which can be understood by 
regular people


  * Company principals with long running solar background...from which we may 
assume that they are familiar with the difficulties that can arise when a 
product is parked outside for years.


  * ...and Joel's remarks about degradation give basic confirmation that the 
product would survive long term. We need more of such confirmation, such as 
accelerated life cycle testing, real modules with UL listings, long warranty 
from strong backers, etc. but it's a good start. 


  *


  What else would I want to see from a new module technology? I would want to 
see a better model for marketing, sales, & distribution than what we now have. 
(I am posting this reply under the RE-Markets list, as well.) 


  The manufacturers of conventional crystalline are in a "race to the bottom" 
because their products have been commoditized, and the profitability of 
wholesalers, value added resellers & contractors has been pounded down in the 
process. It's "wholesale to the public" out there. 


  Some (perhaps to include Joel D.) actually may rejoice to see the precipitous 
price drops because it does mean "more PV". "Power to the People", as one other 
PV pioneer on this list had used as his corporate slogan...and I'm all for 
spreading power around. 


  Consider, too, however, that profitable retailers...profitable 
installers...can be the network through which a new technology gains 
acceptance. Those same "trading partner" type companies can ensure quality 
deployments and good response to concerns or problems at the end user level, 
but only if they can make a good profit by virtue of the business relationship. 
Profitability for their trading partners should matter to a PV manufacturer, 
and that's where leapfrog type technology can play an important role. 


  A company such as Prism Solar must consider what to do with its breakthrough 
PV technology. They can slug it out with First Solar at yard-sale pricing...and 
if the mega-millions are there for enough production volume that could pencil 
out. OR: they could write blanket orders from the many PV wholesalers and stuff 
the pipelines...multiple pipelines which would ensure low markup/low 
profitability at the wholesale level. Then stand back as the wholesalers stuff 
similar multiple pipelines at the retail level, with similar "downward 
pounding" e

Re: [RE-wrenches] The Genie Lens

2010-08-13 Thread Joel Davidson

Wrenches,

Rick Lewandowski (founder of SunWize) and his team have been making PV 
modules with an optical film. See http://www.prismsolar.com/  Prism Solar's 
primary advantage is less PV cell material lowers cost.


How Prism Solar differs from SolOptics:
- film is laminated with the cell so it does not get wet,
- holographic material is UV stable and is used in extraterrestrial 
applications,
- tests have shown PS holograms degrade less than 0.04% per year compared to 
silicon cells at 0.5-1% per year,
- angular and spectral multiplexed holograms result in cooler running cells 
and useful light down to 0.25 suns.


Rick has worked several years to get Prism Solar ready for primetime. See 
their video and live test results and tell me what you think.


Best regards,
Joel Davidson

- Original Message - 
From: "Mark Dickson" 

To: "'RE-wrenches'" 
Sent: Thursday, August 12, 2010 9:43 AM
Subject: Re: [RE-wrenches] The Genie Lens



They claim that their film "should" last the 20 year lifespan of the
modules.  With most warranties at 25 years and modules lasting much longer
than that, that claim does not do them much justice.  I can't imagine
modules will work very well with a tarnished or degrading film on them.
Imagine how pissed a customer would be trying to peel that crap off after 
a

few years getting baked in the sun.
I am sure the module manus would love to disqualify any warranty claims 
that

came back with this stuff on it.

Also, they claim a 4-12.5% increase.

Best regards,

Mark Dickson,
NABCEP Certified Solar PV Installer T
Oasis Montana Inc.


-Original Message-
From: re-wrenches-boun...@lists.re-wrenches.org
[mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Peter
Parrish
Sent: Thursday, August 12, 2010 10:17 AM
To: 'RE-wrenches'
Subject: [RE-wrenches] The Genie Lens

Anybody know anything about these claims?

SolOptics, the solar division of Genie Lens, has created a new lens design
that improves solar PV performance by 12.5 percent. The new thin-film 
design

can be applied to any PV module, just like a sticker. The new design is
created by the company's ray tracing software that embosses 
microstructures

onto thin polymer film. That film can then be applied to solar panels much
like tinting film can be applied to a window. In testing, the
microstructures in the lens improved PV efficiency by 10 to 12.5 percent.

I think the claim of a "lens" is complete hogwash. As for being an
anti-reflective coating, that might work, but reliability would be my
concern (UV, heat, moisture). Think how many tinted car windows you have
seen with blisters all over them?

I am posting this for a client who is a really dedicated solar enthusiast
and occasionally emails me with questions about solar technology.

- Peter


Peter T. Parrish, Ph.D., President
California Solar Engineering, Inc.
820 Cynthia Ave., Los Angeles, CA 90065
CA Lic. 854779, NABCEP Cert. 031806-26
peter.parr...@calsolareng.com
Ph 323-258-8883, Mobile 323-839-6108, Fax 323-258-8885




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Re: [RE-wrenches] NECPLUS Article

2010-08-06 Thread Joel Davidson
Interesting news item, but the link does not connect to the fire fighter 
report. Does someone have the correct report link?
In May 2010 the Fire Protection Research Foundation (FPRF) completed a 
one-year research project addressing photovoltaic (PV) power systems.  The 
report, titled "Fire Fighter and Emergency Response for Solar Power Systems", 
is of direct interest to the NEC® community and is available for download on 
the FPRF website (at www.nfpa.org/foundation).


- Original Message - 
From: 

To: "RE-wrenches" 
Sent: Thursday, August 05, 2010 2:17 PM
Subject: [RE-wrenches] NECPLUS Article



This may be of interest...from the NEC newsletter

http://www.necplus.org/Features/Pages/ThePoweroftheSunResearchinSupportofSafePhotovoltaicPower.aspx?sso=0

Holt E. Kelly
Holtek Fireplace & Solar Products
500 Jewell Dr.
Waco TX. 76712
254-751-9111
www.holteksolar.com

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[RE-wrenches] Fw: Preventing Worker Deaths in the Solar Energy Industry

2010-07-22 Thread Joel Davidson

- Original Message - 
From: face (CDPH-OHB) 
To: undisclosed-recipients: 
Sent: Thursday, July 22, 2010 10:36 AM
Subject: Preventing Worker Deaths in the Solar Energy Industry


California FACE Program Investigates the Deaths of 

Three Solar Installers

 

The California Fatality Assessment and Control Evaluation (FACE) program has 
recently investigated the deaths of three solar installers.  Two of the 
completed reports are now available online:

 

·Electrical worker dies when he falls through a skylight while 
installing solar panels on the roof of a warehouse (09CA003, PDF)

·Solar installer dies when he falls 35 feet from a scaffold after being 
electrocuted (08CA006, PDF)

 

The California FACE program published several fact sheets (available in both 
English and Spanish) based on these fatality investigations.  Fact sheets are 
written for workers, and can easily be incorporated into trainings and posted 
at the worksite: 

 

·Deadly Skylights! Solar Energy and Warehouse Workers Killed! (English 
PDF)  |  Spanish

·Solar Energy Technician Electrocuted! (English PDF)  |  Spanish

·Solar Panels: Lift Them Safely! (PDF)

 

We invite you to explore additional materials on our Web site:  
www.cdph.ca.gov/programs/ohb-face and e-mail f...@cdph.ca.gov for more 
information about this program funded by the National Institute for 
Occupational Safety and Health (NIOSH).

 

If you would like to receive e-mail notification of future California FACE 
work-related fatality investigation reports (including the third solar 
investigation), or would like to provide feedback to our program by evaluating 
any of our materials, please complete this short form:  
http://fs6.formsite.com/BuildSafe/face/ .

 

A complete archive of CA/FACE publications can be viewed at:

 

·http://www.cdph.ca.gov/programs/ohb-face/Pages/Publications.aspx 
(English) or 

·http://www.cdph.ca.gov/programs/ohb-face/Pages/SpanishPubs.aspx 
(Spanish).

 

 

Sincerely, 

 

Robert Harrison, MD, MPH Laura Styles, MPH

Principal Investigator Project 
Coordinator

 
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