Re: [RE-wrenches] Auto Gen on Outback

[Randy Brooks]

Drake,

If the generator has a two wire auto start/stop, then a relay connected to the 
master FX AUX output, that opens and closes the auto start circuit, has worked 
reliably for us on a number of systems.  No need for a GSCM.

Just be sure all the FX charger settings, and MATE AGS settings are as desired. 
 In particular, be sure the DC GENSET is set to "NO", and the VDC GENSTOP is 
set to a high value that will never be reached during normal generator charging 
(the default is high enough).  The VDC GENSTOP will turn off the generator even 
if DC GENSET is set to "NO".  If the value is too low, the normal FX charging 
cycle will be interrupted prematurely.

Good luck,

Randy Brooks
Brooks Solar, Inc.
Solar Power for People
140 Columbia View
Chelan, WA  98816
509-682-9646
ra...@brookssolar.com
www.BrooksSolar.com

On Mar 27, 2013, at 12:51 PM, Drake  
wrote:

> Hello Wrenches,
> 
> We are adding a Generac EcoGen to an existing Outback VFX 3648 system.  It 
> was the recommendations from those of you on this list who have installed 
> them that led to this choice. Your testimonials are very much appreciated.
> 
> I've read, on this list, that people have had issues with FX family inverters 
> starting and stopping generators reliably. The plan was to go with the 
> Atkinson GSCM and a separate voltage controlled relay.  It appears that if 
> the system is 48 volts, it is necessary to center tap the battery bank for a 
> 24 volt feed to the GSCM. This I don't want to do.
> 
> Is it still agreed that the FX inverters are not reliable for starting and 
> stopping generators? 
> 
> Has anyone used a GSCM on a 48 volt system without problems?
> 
> Thank you,
> 
> Drake 
> 
> 
> 
> 
> 
> 
> 
> Drake Chamberlin
> Athens Electric LLC
> OH License 44810
> CO License 3773
> NABCEP Certified Solar PV Installer
> 740-448-7328
> http://athens-electric.com/ 
> 
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Re: [RE-wrenches] Auto Gen on Outback

[penobscotsolar]

Hi Drake,
   We used to have problems with the Outback gen-start s/w, but it seems,
at least over the last year, that Outback has gotten the software
corrected. No complaints from customers over the last year (winter) say
so. Time will tell, but I'm feeling more comfortable with them.

Daryl


> Hello Wrenches,
>
> We are adding a Generac EcoGen to an existing Outback VFX 3648
> system.  It was the recommendations from those of you on this list
> who have installed them that led to this choice. Your testimonials
> are very much appreciated.
>
> I've read, on this list, that people have had issues with FX family
> inverters starting and stopping generators reliably. The plan was to
> go with the Atkinson GSCM and a separate voltage controlled
> relay.  It appears that if the system is 48 volts, it is necessary to
> center tap the battery bank for a 24 volt feed to the GSCM. This I
> don't want to do.
>
> Is it still agreed that the FX inverters are not reliable for
> starting and stopping generators?
>
> Has anyone used a GSCM on a 48 volt system without problems?
>
> Thank you,
>
> Drake
>
>
>
>
>
>
>
> Drake Chamberlin
> Athens Electric LLC
> OH License 44810
> CO License 3773
> NABCEP Certified Solar PV Installer
> 740-448-7328
> http://athens-electric.com/
>
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>


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[RE-wrenches] Auto Gen on Outback

[Drake]

Hello Wrenches,

We are adding a Generac EcoGen to an existing Outback VFX 3648 
system.  It was the recommendations from those of you on this list 
who have installed them that led to this choice. Your testimonials 
are very much appreciated.


I've read, on this list, that people have had issues with FX family 
inverters starting and stopping generators reliably. The plan was to 
go with the Atkinson GSCM and a separate voltage controlled 
relay.  It appears that if the system is 48 volts, it is necessary to 
center tap the battery bank for a 24 volt feed to the GSCM. This I 
don't want to do.


Is it still agreed that the FX inverters are not reliable for 
starting and stopping generators?


Has anyone used a GSCM on a 48 volt system without problems?

Thank you,

Drake







Drake Chamberlin
Athens Electric LLC
OH License 44810
CO License 3773
NABCEP Certified Solar PV Installer
740-448-7328
http://athens-electric.com/

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Re: [RE-wrenches] Shunt question

[Allan Sindelar]

  
  
Wrenches,
Here's one of those threads to save if you expect to do large
multi-inverter battery-based systems. This is a thread from last
August, with recent updates.
Bottom Line: in a large system with Sunny Islands, use a 1,000A/50mV
shunt, not a 1000A/100mV shunt. It's counterintuitive.
Allan

On Tue, Jul 31, 2012 at 6:37 AM, Allan Sindelar 
wrote:

   Wrenches,
What are you using when you need a shunt larger than the
standard 500A/50mV?

The application: four Sunny Islands and a Radian in a large
grid-tie with backup system. Total current flow through B- is
rated 850A (using 125A SI DC breakers) or 1,050A (using 175A DC
breakers) on a single large battery bank. Given uncertain
continuous amperage, I should use a 1,000A shunt or even a
1,200A shunt, as Deltec recommends never exceeding 67% of a
shunt's current rating for long. Deltec makes both; see http://www.deltecco.com/MKC-DC.html.
The shunt will be installed inside of a Nottagutter-8, with a
Midnite shunt bus on each side. The shunt will be used with the
Sunny Island master to control overall SOC and charging
parameters; there's no plan for a Tri-Metric in this system, as
a Sunny Webbox will handle online monitoring per the customer's
wishes.

The 1,000 and 1,200A series MKC Deltec shunts are the same
physical dimensions as the common 500A/50mV units. However, the
larger units are still 50mV. Ralph Heisey of Bogart Engineering,
in his "Information on Shunts" reference article (http://www.deltecco.com/MKC-DC.html),


tells us to match the ratio of voltage drop to current - that
is, just as a 500A shunt drops 50mV, a larger shunt with 1,000A
flowing through it should drop 100mV. But all of the larger
Deltec shunts are still rated 50mV.

Who has done this and resolved the issue? What shunt did you
use?

Thank you,
Allan 

-- 
  Allan
  Sindelar
  al...@positiveenergysolar.com
NABCEP Certified
  Photovoltaic Installer
  NABCEP Certified Technical Sales Professional
  New Mexico EE98J Journeyman Electrician
  Founder and Chief Technology Officer
  Positive Energy, Inc.
  3209 Richards Lane (note new address)
  Santa Fe, New Mexico 87507
  505 424-1112
  www.positiveenergysolar.com
  

  



  

  Date: 
  Tue, 31 Jul 2012 14:11:06 -0700


  From: 
  Bogart Engineering 

  


Hi Allan et al:


Here are some comments about shunts, if you are interested--


Twenty years ago I called Deltec and talked to them about amp
  ratings for shunts-- at that time they said that they never tested
  them themselves-- they just made them "like other manufacturers
  did", then assumed the ratings they were OK.  My impression is
  that the "67% rule" came out of a hat, not out of actual
  measurement.
 
The basic rule is that the shunt material (plates between the
  brass blocks) is and alloy called manganin, (designed for very
  stable resistance under changing temperature.) should not exceed
  140 degrees Celsius (not Fahrenheit) . Incidentally, there is
  surprising disagreement on what this temp should be-- I trusted
  most a German company that sold the manginin material.)  I
  actually measured some shunts and their temperature rise and found
  the 67% rule to be VERY approximate.
  
The temperature rise for one given shunt is going to be
  proportional to the square of the current, so the temp rise at
  100Amps is 30 degrees, for 200 amps it would be 120 degrees. The
  bottom line for this is that it is only when the currents get
  really high could you seriously overheat them. Some may remember
  some so called "200% rated" and even "300% rated" shunts in "the
  old days"  which were hardly different in size from the 100% rated
  ones. Don't know what they were smoking when they came up with
  these. 


So if you really want to know how much a shunt can handle,
  measure the temperature rise right in the center of the plates,
  with a steady 200Amps.  You can pretty much assume that the temp
  rise above that will be proportional to the square of the current.
  You don't want the temp in the center of the plates  to go above
  140 C.  


Frankly, maybe you guys know better, but I can't imagine ever
  going above 500 amps in an

Re: [RE-wrenches] Cable tray

[John Berdner]

Exposed single conductor sunlight resistant cable in cable trays are widely 
used in PV systems outside the US.
There is a very large installed base of systems with good long term performance 
data using this type of construction.
We should not discount the advantages of wire cable trays just because we are 
unfamiliar with it.

Look at data cabling - Characterized by many, relatively small, cables over 
long distances with periodic drops.
Sounds a lot like PV source circuits (other than voltage and current in the 
wires of course).
There are lots of videos out there showing how to pull 10's of pairs of wires 
simultaneously in cable trays.
IMHO, we need to look at ideas like this to reduce installation cost and time.

Installation costs are becoming the tall pole in the tent and new thinking is 
needed.
As systems are falling to sub $3.00 /Watt all-in, running wire in conduit will 
simply not be cost effective.
Running wire in conduit is one of the reasons PV installation costs in the US 
are double (or more) of those in Europe.
As one of my former German colleagues noted:
"It is only in the US where you need first to be a plumber before you can be an 
electrician"

Best Regards,

John Berdner
General Manager, North America

SolarEdge Technologies, Inc.
3347 Gateway Boulevard, Fremont CA 94538 USA  (*Please note of our new address.)
T: 510.498.3200, X 747
M: 530.277.4894

From: re-wrenches-boun...@lists.re-wrenches.org 
[mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Allan Sindelar
Sent: Wednesday, March 27, 2013 8:51 AM
To: RE-wrenches
Subject: Re: [RE-wrenches] Cable tray

Andrew,
We have used #10 USE-2 for about 16 years, and our high-elevation New Mexico 
sun is quite intense. I have yet to see any degradation exceeding fading 
discoloration on any conductors from that far back, even when directly exposed 
to sunlight. No cracking, peeling, delaminating, or hardening.
Allan
Allan Sindelar
al...@positiveenergysolar.com
NABCEP Certified Photovoltaic Installer
NABCEP Certified Technical Sales Professional
New Mexico EE98J Journeyman Electrician
Founder and Chief Technology Officer
Positive Energy, Inc.
3209 Richards Lane (note new address)
Santa Fe, New Mexico 87507
505 424-1112
www.positiveenergysolar.com


On 3/27/2013 8:41 AM, Andrew Truitt wrote:
Bill - What is your take in conductor insulation degradation over time when 
exposed to UV? Regardless of the "sunlight resistant" labeling, USE-2 (and I 
assume PV wire though I haven't seen it yet) does show wear after years of 
exposure to direct sunlight.  Maybe best practice would be to use cable trays 
where conductors are shaded and [properly installed] conduit when exposed to 
direct UV?

- Andrew Truitt


Sent from my iPad

On Mar 26, 2013, at 11:55 PM, "Bill Brooks" 
mailto:billbroo...@yahoo.com>> wrote:
William,

I have all the respect in the world for you, but I'm not referring to "basket 
tray", which is only appropriate for small conductors. I'm talking about 
legitimate cable tray that can be up to 12" wide and that has a top and rungs 
every 12". The main facilities that use it in the United States are large 
industrial facilities. Most electricians don't get to work with it. It is 
clearly superior to EMT and is at least as good as IMC without all the hassle 
of threaded fittings and setting up expansion joints and worrying about 20 
years of conductors thermal cycling. Even the best electricians have problems 
with this stuff.

I am talking about projects with 800 foot long feeder runs. We can bring them 
in the building and build a rack for the conduit or run covered tray outside. 
As the 2014 NEC will require, you will have to use contactor combiners or some 
other means to shut down the conductors inside a building. It's all doable. My 
recommendation after seeing the aftermath of rooftop conduit by good 
electricians is to put cable tray on roofs and use conduit if you bring the 
feeders indoors. It will become common practice soon. Hopefully sooner than 
later.

Bill.

From: 
re-wrenches-boun...@lists.re-wrenches.org
 [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of William Miller
Sent: Tuesday, March 26, 2013 9:49 PM
To: RE-wrenches
Subject: Re: [RE-wrenches] Cable tray

Bill:

I have to disagree with you on this one.  We can not abandoned a tried and true 
practice just because some practitioners don't do it right.  I don't know how 
one can justify saying that encapsulating high voltage conductors in a conduit 
is less safe than exposed in a flimsy basket.  Consider snow and ice and 
falling objects.

Too many installers entered the PV field without first acquiring the necessary 
skills as journeymen or women electricians.  I don't see the benefit of 
rewriting the code to accommodate a lack of skills in the industry.

Respectfully,

William Miller

PS:  The temperature adders al

Re: [RE-wrenches] Cable tray

[Allan Sindelar]

  
  
Andrew,
  We have used #10 USE-2 for about 16 years, and our high-elevation
  New Mexico sun is quite intense. I have yet to see any degradation
  exceeding fading discoloration on any conductors from that far
  back, even when directly exposed to sunlight. No cracking,
  peeling, delaminating, or hardening.
  Allan
  
  


Allan Sindelar
al...@positiveenergysolar.com
  NABCEP Certified Photovoltaic
Installer
NABCEP Certified Technical Sales Professional
New Mexico EE98J Journeyman Electrician
Founder and Chief Technology Officer
Positive Energy, Inc.
3209 Richards Lane (note new address)
Santa Fe, New Mexico 87507
505 424-1112
www.positiveenergysolar.com



 
  On 3/27/2013 8:41 AM, Andrew Truitt wrote:


  
  Bill - What is your take in conductor insulation degradation
over time when exposed to UV? Regardless of the "sunlight
resistant" labeling, USE-2 (and I assume PV wire though I
haven't seen it yet) does show wear after years of exposure to
direct sunlight.  Maybe best practice would be to use cable
trays where conductors are shaded and [properly installed]
conduit when exposed to direct UV?
  
  
  - Andrew Truitt
  

Sent from my iPad
  
On Mar 26, 2013, at 11:55 PM, "Bill Brooks" 
wrote:

  
  

  
  
  
  
William,
 
I
have all the respect in the world for you, but I’m not
referring to “basket tray”, which is only appropriate
for small conductors. I’m talking about legitimate cable
tray that can be up to 12” wide and that has a top and
rungs every 12”. The main facilities that use it in the
United States are large industrial facilities. Most
electricians don’t get to work with it. It is clearly
superior to EMT and is at least as good as IMC without
all the hassle of threaded fittings and setting up
expansion joints and worrying about 20 years of
conductors thermal cycling. Even the best electricians
have problems with this stuff.
 
I
am talking about projects with 800 foot long feeder
runs. We can bring them in the building and build a rack
for the conduit or run covered tray outside. As the 2014
NEC will require, you will have to use contactor
combiners or some other means to shut down the
conductors inside a building. It’s all doable. My
recommendation after seeing the aftermath of rooftop
conduit by good electricians is to put cable tray on
roofs and use conduit if you bring the feeders indoors.
It will become common practice soon. Hopefully sooner
than later.
 
Bill.
 

  
From:
re-wrenches-boun...@lists.re-wrenches.org
[mailto:re-wrenches-boun...@lists.re-wrenches.org]
On Behalf Of William Miller
Sent: Tuesday, March 26, 2013 9:49 PM
To: RE-wrenches
Subject: Re: [RE-wrenches] Cable tray
  

 
Bill:
  
  I have to disagree with you on this one.  We can not
  abandoned a tried and true practice just because some
  practitioners don't do it right.  I don't know how one can
  justify saying that encapsulating high voltage conductors
  in a conduit is less safe than exposed in a flimsy
  basket.  Consider snow and ice and falling objects.
  
  Too many installers entered the PV field without first
  acquiring the necessary skills as journeymen or women
  electricians.  I don't see the benefit of rewriting the
  code to accommodate a lack of skills in the industry.
  
  Respectfully,
  
  William Miller
  
  PS:  The temperature adders always encourage us to enter
  the building envelope at the first appropriate location to
  avoid adding them.  Thoughtful installers will do the
  same.
  
  Wm
  
  
  At 10:15 PM 3/25/2013, you wrote:
  
  
Content-Type: multipart/alternative;
 

Re: [RE-wrenches] P1 micro performance

[Bill Brooks]

Carl,

 

Just to be clear, the performance tests mandated by the California Energy
Commission, that all products in the U.S. follow, require that the maximum
power rating is continuous (24/7). Actually, continuous means that it can
operate for 3 hours straight at 40C (104F) (really hot). This does not mean
it will last forever. That is an engineering decision on how close the
manufacturer wants to operate their product up to maximum temperature of the
components in the device. Some products may publish a maximum power that is
higher than the maximum continuous power at 40C.

 

Bill.

 

From: re-wrenches-boun...@lists.re-wrenches.org
[mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Carl Emerson
Sent: Tuesday, March 26, 2013 5:29 PM
To: 'RE-wrenches'
Subject: Re: [RE-wrenches] P1 micro performance

 

Friends,

 

Keeping the record straight.

 

I need to say that I have had correspondence 'off list' from a development
engineer from a prominent manufacturer who assures me that his product is
designed to run 'flat out' 24/7. 

 

The unit in fact is just coasting at it's maximum power rating. 

 

This allows for a projected life matching that of the PV.

 

In this case power clipping will not shorten the products life.

 

I am unable to confirm if all manufacturers are taking this approach, buyer
beware.

 

Regards
Carl Emerson

 

Nick,

 

Is Enphase going to be introducing to market any time in the near-term a new
micro with a higher output?  It seems very likely that the trend toward
higher output mods will continue.  The M215 will surely be left behind to a
greater degree as this trend continues if there are higher and reliable and
comparably priced, on a dollar/watt basis, micros available.

 

Thanks,

marco

 

Hi Carl, Marco, and Wrenches,

As a longtime installer, I understand your point of view.  Historically, I
designed my string and microinverter systems with the same consideration for
maintaining conservative DC to AC ratios.  That being said, the costs of
modules have decreased significantly and the dynamics have changed.  Solar
companies should be focused on selling systems that offers a great rate of
return.  Maximizing the customer's investment is most important.  Isn't that
what your customer wants?

What Enphase is encouraging is the development of cost effective PV systems
that will generate a healthy return.  Considering that the modules are only
20% of the total system costs today, it is smart to give up 0.2% or more of
the module production to lower the overall system costs by 5-10%.  The NEC
requires that the AC panel boards, conductors, and circuit breakers are
sized to the inverter continuous output current rating.  We should be
maximizing this infrastructure.

 

The data available indicates that when a system is installed with a 1.2 to
1.25 DC to AC ratio, it will rarely operate at peak output.  Installing a PV
system with a 1.25 DC to AC ratio is not driving the equipment to the
maximum.  In the case of the Enphase M215s; they are designed to operate
continuously at peak output, so reaching that level a few hours in the first
years is not problematic.  To be clear, this limiting will occur the most
during the spring months, because you have a combination of both cool
weather and high irradiance levels.

As Dan mentioned, this applies to string inverters as well as
microinverters.  One of the most common system designs of the early US
grid-tied market was installing 18- 165 watt modules on an SWR-2500.  I
designed hundreds of projects like that.  That was a ~1.2 multiplier, and
was at a time when the modules cost $5 per watt; not $1 per watt.  Why be
more conservative now?

  

 
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Re: [RE-wrenches] Cable tray

[Andrew Truitt]

Bill - What is your take in conductor insulation degradation over time when 
exposed to UV? Regardless of the "sunlight resistant" labeling, USE-2 (and I 
assume PV wire though I haven't seen it yet) does show wear after years of 
exposure to direct sunlight.  Maybe best practice would be to use cable trays 
where conductors are shaded and [properly installed] conduit when exposed to 
direct UV?

- Andrew Truitt


Sent from my iPad

On Mar 26, 2013, at 11:55 PM, "Bill Brooks"  wrote:

> William,
>  
> I have all the respect in the world for you, but I’m not referring to “basket 
> tray”, which is only appropriate for small conductors. I’m talking about 
> legitimate cable tray that can be up to 12” wide and that has a top and rungs 
> every 12”. The main facilities that use it in the United States are large 
> industrial facilities. Most electricians don’t get to work with it. It is 
> clearly superior to EMT and is at least as good as IMC without all the hassle 
> of threaded fittings and setting up expansion joints and worrying about 20 
> years of conductors thermal cycling. Even the best electricians have problems 
> with this stuff.
>  
> I am talking about projects with 800 foot long feeder runs. We can bring them 
> in the building and build a rack for the conduit or run covered tray outside. 
> As the 2014 NEC will require, you will have to use contactor combiners or 
> some other means to shut down the conductors inside a building. It’s all 
> doable. My recommendation after seeing the aftermath of rooftop conduit by 
> good electricians is to put cable tray on roofs and use conduit if you bring 
> the feeders indoors. It will become common practice soon. Hopefully sooner 
> than later.
>  
> Bill.
>  
> From: re-wrenches-boun...@lists.re-wrenches.org 
> [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of William Miller
> Sent: Tuesday, March 26, 2013 9:49 PM
> To: RE-wrenches
> Subject: Re: [RE-wrenches] Cable tray
>  
> Bill:
> 
> I have to disagree with you on this one.  We can not abandoned a tried and 
> true practice just because some practitioners don't do it right.  I don't 
> know how one can justify saying that encapsulating high voltage conductors in 
> a conduit is less safe than exposed in a flimsy basket.  Consider snow and 
> ice and falling objects.
> 
> Too many installers entered the PV field without first acquiring the 
> necessary skills as journeymen or women electricians.  I don't see the 
> benefit of rewriting the code to accommodate a lack of skills in the industry.
> 
> Respectfully,
> 
> William Miller
> 
> PS:  The temperature adders always encourage us to enter the building 
> envelope at the first appropriate location to avoid adding them.  Thoughtful 
> installers will do the same.
> 
> Wm
> 
> 
> At 10:15 PM 3/25/2013, you wrote:
> 
> Content-Type: multipart/alternative;
> boundary="=_NextPart_000_00E3_01CE29A6.37CC5110"
> Content-Language: en-us
> 
> William,
>  
> I would strongly disagree that conduit is tried and true on rooftops. I have 
> rarely seen good conduit runs on rooftops. Most electricians have no clue how 
> to work with expansion joints. Conduit on rooftops is a bad idea in general. 
> Most conduit runs in big buildings are all done indoors for good reason. We 
> are the crazy people doing things on the roof. 
>  
> The sooner we get away from conduit­particularly for long feeder runs­the 
> better.
>  
> In Europe they don’t have problems with their rooftop wiring systems because 
> everything is in tray.
>  
> For those that don’t allow cable tray for anything less than 1/0, just 
> remember that if it isn’t called cable tray, then 392 doesn’t apply. The NEC 
> would allow us to use treated lumber in place of cable tray. This makes no 
> sense.
>  
> We did some research on the origin of the 1/0 requirement, and it is ancient 
> and no longer relevant. Just because it is in the code, does not mean it is 
> correct. That’s why we try to fix it every three years.
>  
> Bill.
>  
>  
> 
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