Re: [RE-wrenches] mounting hardware and U.L.

[Phil Undercuffler]

I don't think it's formally ratified, certified and adopted, but
UL2703 is the new proposed "Standard for Mounting Systems, Mounting
Devices, Clamping/Retention Devices, and Ground Lugs for Use with
Flat-Plate Photovoltaic Modules and Panels."  Also check out
SolarABCs.org for an update, there is a new report on this topic.

Phil

On Thu, Jul 19, 2012 at 4:12 PM, Jay Peltz  wrote:
> Is unistrut UL?
>
> Kay
>
> Peltz power
>
> Sent from my iPhone
>
> On Jul 19, 2012, at 6:36 PM, "Marco Mangelsdorf" 
> wrote:
>
> Does anyone know whether there are U.L. standards when it comes to PV
> mounting hardware?
>
>
>
> That is, are there any mounting hardware manufacturers (UniRac, Professional
> Solar Products, DPW, Schletter) who have achieved U.L. listing/approval for
> their stuff?
>
>
>
> After using PSP for the past 12 years here on the Big Island of Hawaii, now,
> all of a sudden the new building division head is taking an interest as to
> whether PSP hardware is U.L. something or other.
>
>
>
> So very frustrating
>
>
>
> Thanks,
>
> marco
>
>
>
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Re: [RE-wrenches] mounting hardware and U.L.

[R Ray Walters]

I don't think any bolts, washers, nuts, screws, lags, all thread, etc are UL 
listed either.  There aren't UL batteries, so they can't prevent us from 
powering off grid homes.  Is concrete UL listed, when we do a ground mount 
array or a Uffer ground?  
The card being played here is article 110.2 'equipment shall be acceptable only 
if approved';  then article 100 defines approved as being 'acceptable to the 
AHJ'  I call this little bit of NEC BS, the AHJ = God conundrum.  110.3 (A) 
provides many other criteria besides listing to verify the acceptability of 
equipment, so regardless of the seemingly omnipotent 110.2, an AHJ can't 
reasonably require equipment that doesn't exist.

Ray

On Jul 19, 2012, at 5:12 PM, Jay Peltz wrote:

> Is unistrut UL?
> 
> Kay
> 
> Peltz power
> 
> Sent from my iPhone
> 
> On Jul 19, 2012, at 6:36 PM, "Marco Mangelsdorf"  wrote:
> 
>> Does anyone know whether there are U.L. standards when it comes to PV 
>> mounting hardware?
>>  
>> That is, are there any mounting hardware manufacturers (UniRac, Professional 
>> Solar Products, DPW, Schletter) who have achieved U.L. listing/approval for 
>> their stuff?
>>  
>> After using PSP for the past 12 years here on the Big Island of Hawaii, now, 
>> all of a sudden the new building division head is taking an interest as to 
>> whether PSP hardware is U.L. something or other.
>>  
>> So very frustrating
>>  
>> Thanks,
>> marco
>>  
>> ___
>> List sponsored by Home Power magazine
>> 
>> List Address: RE-wrenches@lists.re-wrenches.org
>> 
>> Options & settings:
>> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>> 
>> List-Archive: 
>> http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
>> 
>> List rules & etiquette:
>> www.re-wrenches.org/etiquette.htm
>> 
>> Check out participant bios:
>> www.members.re-wrenches.org
>> 
> ___
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Re: [RE-wrenches] Small battery bank vs too large array

[Phil Undercuffler]

OutBack implemented Global Charge Control in the FM charge controllers
a while back, based on the input of the good folk at SELF who worked
to power a number of hospitals and clinics in Haiti after the
earthquake.  In some of those systems, the PV array was based on the
typical running consumption of the hospital, in the 30 - 100 kW if I
remember right, and the battery bank was relatively modest. However,
on the weekends and holidays without the normal AC loads the PV input
was considerably more than the battery could absorb without
destructive heating, something like a C2 or C5 rate.

Global Charge Control is implemented using the MATE3, a FN-DC and FM
charge controllers set to GT mode.  You set a high charge current
limit in the M3, and then it monitors the charge current going to the
batteries.  In normal operating mode the controllers stay in wide open
mode, harvesting as much power as possible.  However if the loads drop
and the total current from the charging sources begin exceed the
global charge limit, the system compensates and the controllers back
off to prevent sending too much current to the batteries.

In today's world of PV modules being cheaper than diesel, we're seeing
a lot more systems that can use this tool.

Hope this helps,

Phil



On Thu, Jul 19, 2012 at 7:56 PM, b...@midnitesolar.com
 wrote:
>
>
> I didn't see that Brian T had the same idea until after I sent that email
> off to Allan...
> boB
>
>
>
>
>
> On 7/19/2012 7:53 PM, Allan Sindelar wrote:
>
> Wrenches,
> I forwarded Brian's post on to Robin at Midnite, as I thought it was an
> interesting idea. Below is his response, as well as boB's.
> 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
>
> Allan, It is simpler than what is being suggested. The reason they want to
> limit to 20 amps is because the battery doesn’t need anymore than that. The
> controller will automatically limit the charge current as the battery gets
> full. If a large load is turned on, the controller will try to refill the
> battery up to its capacity. The 80 amps will quickly be reduced because the
> voltage will rise to the point where the charge tapers off.
>
> There is nothing else that needs to be done. If the problem is that the
> battery bank is too small for a big controller, the best answer is to get
> more batteries. A 80 amp charger into a 200 amp hour battery is going to
> raise the battery voltage so quick, it will not affect the battery at all.
> By the way, discharging a battery at 60 or 80 amps is probably going to do
> damage to a small battery also. We do have an input on the Classic that
> could probably be programmed to do as requested. That input feature has yet
> to be implemented. I’m sure we will have discussions about this when the
> time comes to write the input code. Maybe this feature will be designed in,
> but it doesn’t sound like it is a very good feature to spend a bunch of time
> on. After all, the main problem is that the battery bank is just too darned
> small.
>
> Bob, Tom and Ryan do you have any comments on the subject?
>
> Thanks,
>
> Robin
>
>
>
> One idea I had in mind was to have an option, in software, to limit the
> current into the battery,
> when the charging current goes above some set threshold.  The controller
> would have to get its information from
> the battery monitor over the network.
>
> If it is a grid tie system and grid is there and GT inverter is selling,
> then no problem...  The controller
> can work at its full output.  If grid or loads go away, then the CC will
> know and it can throttle back at
> that time.
>
> We don't have a battery monitor yet, but we will have one.  This will be one
> of the settings as well as
> Re-Bulk based on state of charge, ending amps and those types of things.
>
> boB
>
> On 7/19/2012 8:34 PM, maver...@mavericksolar.com wrote:
>
> I say it is waste of time.
>
> 1. AGM batteries can take the high current and you are right, the absorb
> voltage is reached and the absorb current is tapered rather quickly. Current
> generation charge controllers are rather fast at the transitions. I have a
> bunch of data from a system with a PentaMetric that shows the battery bank
> going to absorb voltage at grid tie, during cloud events, but only for a few
> seconds at a time.
>
> 2. A properly designed GTBB system should cover the connected loads for 24
> hours of each sunny day, at a minimum. Keep in mind, off grid systems are
> designed for that, and 3 days + of backup, etc.
>
> 3. I would say, based on my experience, the minimum battery bank should be
> 400Ah. I personally try to set it at 600Ah (48V). It is a backup system
> after all. But the key is the customer's ex

Re: [RE-wrenches] Array direct farm machinery?

[Dan Fink]

Hi Eric;

Not a crazy idea, but not really simple either. Water pumping, ventilation
and water aeration are ideal loads for PV Direct systems, as there's no
problem if they are not running at full capacity when insolation is low.
Grinding grain, pressing oil, etcnot enough irradiation, and everything
comes to a halt.

You'll have to gauge the difficulty and cost of (possibly) custom MPPT/LCB
controllers for the other equipment (they are cheap and off the shelf for
water pumping) vs. the cost of a simple battery/inverter system, which does
a great job controlling energy to motors and is again off the shelf.


-- 
Dan Fink,
Executive Director;
Otherpower
Buckville Energy Consulting
Buckville Publications LLC
NABCEP / IREC accredited Continuing Education Providers
970.672.4342 (voicemail)


On Thu, Jul 19, 2012 at 4:20 PM, Eric Youngren wrote:

> Howdy Wrenches,
>
> We are thinking up new ideas for powering agriculture in the rural
> developing world to propose for the new USAID "Energy Grand Challenge for
> Development" 
>
> One idea is to build PV array direct water pumping systems for irrigation
> that could be converted to power productive use farm machinery for grain
> milling, oil pressing or other farm processing jobs after the harvest is
> in.  The idea being that after the harvest they don't need the irrigation
> pumping for a bit and the PV array could be switched over to drive a motor
> to accomplish a mechanical task.  For that matter if it was an easy swap
> (Anderson 2 pole connectors, dual battery boat switches, etc) between the
> pumping load and the machinery load the same PV array could be used on any
> given day to either run the pump or the machine(s). I'd like to avoid
> batteries altogether and I'd like to allow a single 1 to 3 kW PV array to
> accomplish multiple array direct mechanical tasks.
>
> This is just a brainstorm at this point,  maybe this is a crazy idea and
> not worth pursuing, but I'd be really curious if anybody has any experience
> doing anything like this or any other ideas to bring to the table.
>
> Any ideas?  Thanks!
>
> Eric Youngren
> Solar Nexus International
> www.solarnexusinternational.com
>
>
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Re: [RE-wrenches] Small battery bank vs too large array

[b...@midnitesolar.com]

I didn't see that Brian T had the same idea until after I sent that 
email off to Allan...

boB




On 7/19/2012 7:53 PM, Allan Sindelar wrote:

Wrenches,
I forwarded Brian's post on to Robin at Midnite, as I thought it was 
an interesting idea. Below is his response, as well as boB's.

Allan

*Allan Sindelar*
_Allan@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_ 

Allan, It is simpler than what is being suggested. The reason they 
want to limit to 20 amps is because the battery doesn't need anymore 
than that. The controller will automatically limit the charge current 
as the battery gets full. If a large load is turned on, the controller 
will try to refill the battery up to its capacity. The 80 amps will 
quickly be reduced because the voltage will rise to the point where 
the charge tapers off.


There is nothing else that needs to be done. If the problem is that 
the battery bank is too small for a big controller, the best answer is 
to get more batteries. A 80 amp charger into a 200 amp hour battery is 
going to raise the battery voltage so quick, it will not affect the 
battery at all. By the way, discharging a battery at 60 or 80 amps is 
probably going to do damage to a small battery also. We do have an 
input on the Classic that could probably be programmed to do as 
requested. That input feature has yet to be implemented. I'm sure we 
will have discussions about this when the time comes to write the 
input code. Maybe this feature will be designed in, but it doesn't 
sound like it is a very good feature to spend a bunch of time on. 
After all, the main problem is that the battery bank is just too 
darned small.


Bob, Tom and Ryan do you have any comments on the subject?

Thanks,

Robin

*
*


One idea I had in mind was to have an option, in software, to limit 
the current into the battery,
when the charging current goes above some set threshold.  The 
controller would have to get its information from

the battery monitor over the network.

If it is a grid tie system and grid is there and GT inverter is 
selling, then no problem...  The controller
can work at its full output.  If grid or loads go away, then the CC 
will know and it can throttle back at

that time.

We don't have a battery monitor yet, but we will have one. This will 
be one of the settings as well as

Re-Bulk based on state of charge, ending amps and those types of things.

boB

On 7/19/2012 8:34 PM, maver...@mavericksolar.com wrote:

I say it is waste of time.

1. AGM batteries can take the high current and you are right, the 
absorb voltage is reached and the absorb current is tapered rather 
quickly. Current generation charge controllers are rather fast at the 
transitions. I have a bunch of data from a system with a PentaMetric 
that shows the battery bank going to absorb voltage at grid tie, 
during cloud events, but only for a few seconds at a time.


2. A properly designed GTBB system should cover the connected loads 
for 24 hours of each sunny day, at a minimum. Keep in mind, off grid 
systems are designed for that, and 3 days + of backup, etc.


3. I would say, based on my experience, the minimum battery bank 
should be 400Ah. I personally try to set it at 600Ah (48V). It is a 
backup system after all. But the key is the customer's 
expectations...who are they going to call after the lights go out?



Thank you,

Maverick


Maverick Brown
BSEET, NABCEP Certified Solar PV Installer ®
President & CEO
Maverick Solar Enterprises, Inc.
Office: 512-919-4493
Cell:512-460-9825

Sent from my HondaJet!

On Jul 19, 2012, at 6:35 PM, Brian Teitelbaum 
mailto:bteitelb...@aeesolar.com>> wrote:



Drake,

I've been hounding a couple of the charge controller manufactures 
about this issue, but so far I just haven't seen a light bulb go off 
in their heads, but I'll keep trying, and maybe this is a better 
forum to do it.


MPPT controllers can be adjusted to current limit at amperage values 
below their rating, but if you do that, you are also limiting the 
output of the array in general, and the amount of PV power available 
to run the loads directly from the array (through the inverter). Not 
the best use of available PV power.


Say you have an 80A controller and a 200AH battery. With current 
technology, you have two choices:


Let the controller operate at 80A. If you have loads to draw off 
some of the current (or sell to the grid), great, but if not you 
could be seeing a charge rate of C/2.5, which would be pretty hard 
on a sealed 200AH battery, to say the least. Granted, the battery 
voltage would rise pretty quickly, and the controller would start to 
taper off, but

Re: [RE-wrenches] Small battery bank vs too large array

[Allan Sindelar]

  
  
Wrenches,
  I forwarded Brian's post on to Robin at Midnite, as I thought it
  was an interesting idea. Below is his response, as well as boB's.
  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

  
Allan,

It is simpler than what is being suggested. The reason they
want to limit to 20 amps is because the battery doesn’t need
anymore than that. The controller will automatically limit
the charge current as the battery gets full. If a large load
is turned on, the controller will try to refill the battery
up to its capacity. The 80 amps will quickly be reduced
because the voltage will rise to the point where the charge
tapers off.
There

is nothing else that needs to be done. If the problem is
that the battery bank is too small for a big controller, the
best answer is to get more batteries. A 80 amp charger into
a 200 amp hour battery is going to raise the battery voltage
so quick, it will not affect the battery at all. By the way,
discharging a battery at 60 or 80 amps is probably going to
do damage to a small battery also. We do have an input on
the Classic that could probably be programmed to do as
requested. That input feature has yet to be implemented. I’m
sure we will have discussions about this when the time comes
to write the input code. Maybe this feature will be designed
in, but it doesn’t sound like it is a very good feature to
spend a bunch of time on. After all, the main problem is
that the battery bank is just too darned small. 
Bob,
Tom and Ryan do you have any comments on the subject?
Thanks,
Robin



One idea I had in mind was to have an option, in software, to
limit the current into the battery,
when the charging current goes above some set threshold.  The
controller would have to get its information from
the battery monitor over the network.

If it is a grid tie system and grid is there and GT inverter is
selling, then no problem...  The controller
can work at its full output.  If grid or loads go away, then the
CC will know and it can throttle back at
that time.

We don't have a battery monitor yet, but we will have one.  This
will be one of the settings as well as
Re-Bulk based on state of charge, ending amps and those types of
things.

boB

  
  On 7/19/2012 8:34 PM, maver...@mavericksolar.com wrote:


  I say it is waste of time. 
  
  
  1. AGM batteries can take the high current and you are right,
the absorb voltage is reached and the absorb current is tapered
rather quickly. Current generation charge controllers are rather
fast at the transitions. I have a bunch of data from a system
with a PentaMetric that shows the battery bank going to absorb
voltage at grid tie, during cloud events, but only for a few
seconds at a time.
  
  
  2. A properly designed GTBB system should cover the connected
loads for 24 hours of each sunny day, at a minimum. Keep in
mind, off grid systems are designed for that, and 3 days + of
backup, etc.
  
  
  3. I would say, based on my experience, the minimum battery
bank should be 400Ah. I personally try to set it at 600Ah (48V).
It is a backup system after all. But the key is the customer's
expectations...who are they going to call after the lights go
out?



Thank you,


Maverick




Maverick Brown
BSEET, NABCEP Certified Solar PV Installer ®
President & CEO
Maverick Solar Enterprises, Inc.
Office:     512-919-4493
Cell:        512-460-9825


Sent from my HondaJet!
  
On Jul 19, 2012, at 6:35 PM, Brian Teitelbaum 
wrote:

  
  

  
  
  
  
Drake,
 
I’ve
been hounding a couple of the charge controller
  

Re: [RE-wrenches] Small battery bank vs too large array

[Drake]

Brian: Thanks for the clarification, it saved a 
phone call to Outback.  That is how I think it 
works also.  It seems that a current activated 
relay to disconnect strings, to bring the charge 
rate into line with the battery bank, could  be 
an answer.  I don't know what equipment is 
available.  A device that could read the current 
from a shunt and generate a signal could be a solution.


Jason:  The regulation of the CC might take care 
of things but I'm concerned that the C/2.5 would 
occur for too long before the voltage got high 
enough to activate the charge control.  AC 
coupling could be a problem, since the full 
output of a direct grid-tie inverter goes 
straight to the batter without any controls 
(unless dump or other loads are present).  A 
coordinated system of dump loads, using a Morningstar Relay driver could work.


Todd:  We just got done with an extended power 
outage here, and people with direct grid tie PV 
are looking for ways to have power when the sun 
shines.  Many people ran their generators for a 
couple of hours at a time to cool their 
refrigerators and freezers, then lent them to 
their neighbors to do the same.  Having power 
during the day would have been a great help.  A 
bank of 4, 220 AH AGM batteries would allow for 
CF lights, music and computers after dark. 
Batteries are expensive and have a shelf 
life.  They also take up a lot of space.  We are 
trying to minimize these issues.


Cheers,

Drake

At 07:35 PM 7/19/2012, you wrote:

Content-Language: en-US
Content-Type: multipart/alternative;

boundary="_000_8961DF9D3453CF41A4A5B6E6BECA4C770B17874813VSSJEXCH01rec_"

Drake,

I’ve been hounding a couple of the charge 
controller manufactures about this issue, but so 
far I just haven’t seen a light bulb go off in 
their heads, but I’ll keep trying, and maybe this is a better forum to do it.


MPPT controllers can be adjusted to current 
limit at amperage values below their rating, but 
if you do that, you are also limiting the output 
of the array in general, and the amount of PV 
power available to run the loads directly from 
the array (through the inverter). Not the best use of available PV power.


Say you have an 80A controller and a 200AH 
battery. With current technology, you have two choices:


Let the controller operate at 80A. If you have 
loads to draw off some of the current (or sell 
to the grid), great, but if not you could be 
seeing a charge rate of C/2.5, which would be 
pretty hard on a sealed 200AH battery, to say 
the least. Granted, the battery voltage would 
rise pretty quickly, and the controller would 
start to taper off, but it would still see high 
currents especially if the absorption time is set long. Not a happy scenario.


Or, you can set the current limiting on the 
controller to 20A for a C/10 charge rate. But if 
you had loads drawing 60A, you would be pulling 
that additional 40A from the battery and not 
using the array’s full power. Also not a happy scenario.


What we need is a controller that can read the 
signal from a shunt at the battery, and use that 
as the basis of current limiting control.


For example, if we have an array that can 
produce 80A of current, but we want to limit the 
battery to 20A of charge, there would be 60A of 
potential current there to run loads without 
drawing on the battery. If there are no loads 
running, the controller should current limit at 
20A (reading from a shunt), but if loads are 
turned on, the controller should be able to let 
more current through while still limiting the 
battery to 20A. When loads are shut off, the 
controller should go back to a 20A limit.


This doesn’t all have to happen very quickly as 
a battery can take a heavier charge for a short 
period of time, but I think that this would be a 
major improvement of controller function.


Of course, if you are grid-tied you can sell all 
the excess power, but if the grid goes down, or you are off-grid….?


Because of the low cost of PV and the high cost 
of batteries these days, I’m seeing more and 
more requests for large arrays with smaller 
batteries. I also think that PV is now cheap 
enough to allow for oversizing of arrays for 
better battery charging on cloudy days, which 
can reduce generator run times. We need smarter controllers.


What say ye, charge controller gurus?

Brian Teitelbaum
AEE Solar

From: re-wrenches-boun...@lists.re-wrenches.org 
[mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Drake

Sent: Thursday, July 19, 2012 2:21 PM
To: RE-wrenches
Subject: [RE-wrenches] Small battery bank vs too large array

Hello Wrenches,

Where can I get a device that will measure 
current through a shunt and create a signal to trigger a relay?


We want to be able to use a 2 kW array with 
four, 200 AH sealed batteries on an Outback 
system.  2 kW of PV would be too much amperage 
for the batteries.  The idea is to open relays 
to disengage strings in conditions of high current to the batteries.


The reason 

Re: [RE-wrenches] Small battery bank vs too large array

[maver...@mavericksolar.com]

I say it is waste of time. 

1. AGM batteries can take the high current and you are right, the absorb 
voltage is reached and the absorb current is tapered rather quickly. Current 
generation charge controllers are rather fast at the transitions. I have a 
bunch of data from a system with a PentaMetric that shows the battery bank 
going to absorb voltage at grid tie, during cloud events, but only for a few 
seconds at a time.

2. A properly designed GTBB system should cover the connected loads for 24 
hours of each sunny day, at a minimum. Keep in mind, off grid systems are 
designed for that, and 3 days + of backup, etc.

3. I would say, based on my experience, the minimum battery bank should be 
400Ah. I personally try to set it at 600Ah (48V). It is a backup system after 
all. But the key is the customer's expectations...who are they going to call 
after the lights go out?


Thank you,

Maverick


Maverick Brown
BSEET, NABCEP Certified Solar PV Installer ®
President & CEO
Maverick Solar Enterprises, Inc.
Office: 512-919-4493
Cell:512-460-9825

Sent from my HondaJet!

On Jul 19, 2012, at 6:35 PM, Brian Teitelbaum  wrote:

> Drake,
>  
> I’ve been hounding a couple of the charge controller manufactures about this 
> issue, but so far I just haven’t seen a light bulb go off in their heads, but 
> I’ll keep trying, and maybe this is a better forum to do it.
>  
> MPPT controllers can be adjusted to current limit at amperage values below 
> their rating, but if you do that, you are also limiting the output of the 
> array in general, and the amount of PV power available to run the loads 
> directly from the array (through the inverter). Not the best use of available 
> PV power.
>  
> Say you have an 80A controller and a 200AH battery. With current technology, 
> you have two choices:
>  
> Let the controller operate at 80A. If you have loads to draw off some of the 
> current (or sell to the grid), great, but if not you could be seeing a charge 
> rate of C/2.5, which would be pretty hard on a sealed 200AH battery, to say 
> the least. Granted, the battery voltage would rise pretty quickly, and the 
> controller would start to taper off, but it would still see high currents 
> especially if the absorption time is set long. Not a happy scenario.
>  
> Or, you can set the current limiting on the controller to 20A for a C/10 
> charge rate. But if you had loads drawing 60A, you would be pulling that 
> additional 40A from the battery and not using the array’s full power. Also 
> not a happy scenario.
>  
> What we need is a controller that can read the signal from a shunt at the 
> battery, and use that as the basis of current limiting control.
>  
> For example, if we have an array that can produce 80A of current, but we want 
> to limit the battery to 20A of charge, there would be 60A of potential 
> current there to run loads without drawing on the battery. If there are no 
> loads running, the controller should current limit at 20A (reading from a 
> shunt), but if loads are turned on, the controller should be able to let more 
> current through while still limiting the battery to 20A. When loads are shut 
> off, the controller should go back to a 20A limit.
>  
> This doesn’t all have to happen very quickly as a battery can take a heavier 
> charge for a short period of time, but I think that this would be a major 
> improvement of controller function.
>  
> Of course, if you are grid-tied you can sell all the excess power, but if the 
> grid goes down, or you are off-grid….?
>  
> Because of the low cost of PV and the high cost of batteries these days, I’m 
> seeing more and more requests for large arrays with smaller batteries. I also 
> think that PV is now cheap enough to allow for oversizing of arrays for 
> better battery charging on cloudy days, which can reduce generator run times. 
> We need smarter controllers.
>  
> What say ye, charge controller gurus?
>  
> Brian Teitelbaum
> AEE Solar
>  
> From: re-wrenches-boun...@lists.re-wrenches.org 
> [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Drake
> Sent: Thursday, July 19, 2012 2:21 PM
> To: RE-wrenches
> Subject: [RE-wrenches] Small battery bank vs too large array
>  
> Hello Wrenches,
> 
> Where can I get a device that will measure current through a shunt and create 
> a signal to trigger a relay?   
> 
> We want to be able to use a 2 kW array with four, 200 AH sealed batteries on 
> an Outback system.  2 kW of PV would be too much amperage for the batteries.  
> The idea is to open relays to disengage strings in conditions of high current 
> to the batteries.
> 
> The reason for this is to create backup systems where power will be 
> abundantly available when the sun shines. The system will normally connect to 
> the grid, except during outages.  In normal charging conditions the power 
> will go straight to the grid.  When the grid is down, power will be available 
> for loads and battery charging, but batteries 

Re: [RE-wrenches] Small battery bank vs too large array

[toddcory]

what is the point of having battery backup if is is so small as to not really 
be able to back anything up (except when the sun is shining)?
 
this seems like a system design error rather than a charge controller problem.
 
my .02
 
todd
 
 
 
 
On Thursday, July 19, 2012 4:35pm, "Brian Teitelbaum" 
 said:




Drake,
 
I’ve been hounding a couple of the charge controller manufactures about this 
issue, but so far I just haven’t seen a light bulb go off in their heads, but 
I’ll keep trying, and maybe this is a better forum to do it.
 
MPPT controllers can be adjusted to current limit at amperage values below 
their rating, but if you do that, you are also limiting the output of the array 
in general, and the amount of PV power available to run the loads directly from 
the array (through the inverter). Not the best use of available PV power.
 
Say you have an 80A controller and a 200AH battery. With current technology, 
you have two choices:
 
Let the controller operate at 80A. If you have loads to draw off some of the 
current (or sell to the grid), great, but if not you could be seeing a charge 
rate of C/2.5, which would be pretty hard on a sealed 200AH battery, to say the 
least. Granted, the battery voltage would rise pretty quickly, and the 
controller would start to taper off, but it would still see high currents 
especially if the absorption time is set long. Not a happy scenario.
 
Or, you can set the current limiting on the controller to 20A for a C/10 charge 
rate. But if you had loads drawing 60A, you would be pulling that additional 
40A from the battery and not using the array’s full power. Also not a happy 
scenario.
 
What we need is a controller that can read the signal from a shunt at the 
battery, and use that as the basis of current limiting control. 
 
For example, if we have an array that can produce 80A of current, but we want 
to limit the battery to 20A of charge, there would be 60A of potential current 
there to run loads without drawing on the battery. If there are no loads 
running, the controller should current limit at 20A (reading from a shunt), but 
if loads are turned on, the controller should be able to let more current 
through while still limiting the battery to 20A. When loads are shut off, the 
controller should go back to a 20A limit.
 
This doesn’t all have to happen very quickly as a battery can take a heavier 
charge for a short period of time, but I think that this would be a major 
improvement of controller function.
 
Of course, if you are grid-tied you can sell all the excess power, but if the 
grid goes down, or you are off-grid….?
 
Because of the low cost of PV and the high cost of batteries these days, I’m 
seeing more and more requests for large arrays with smaller batteries. I also 
think that PV is now cheap enough to allow for oversizing of arrays for better 
battery charging on cloudy days, which can reduce generator run times. We need 
smarter controllers.
 
What say ye, charge controller gurus?
 
Brian Teitelbaum
AEE Solar
 


From: re-wrenches-boun...@lists.re-wrenches.org 
[mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Drake
Sent: Thursday, July 19, 2012 2:21 PM
To: RE-wrenches
Subject: [RE-wrenches] Small battery bank vs too large array
 
Hello Wrenches,

Where can I get a device that will measure current through a shunt and create a 
signal to trigger a relay?   

We want to be able to use a 2 kW array with four, 200 AH sealed batteries on an 
Outback system.  2 kW of PV would be too much amperage for the batteries.  The 
idea is to open relays to disengage strings in conditions of high current to 
the batteries.

The reason for this is to create backup systems where power will be abundantly 
available when the sun shines. The system will normally connect to the grid, 
except during outages.  In normal charging conditions the power will go 
straight to the grid.  When the grid is down, power will be available for loads 
and battery charging, but batteries will be protected from overcharge?

Any suggestions on ways to accomplish this are welcome!

Thanks

Drake 


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


Sent from Finest Planet WebMail.
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Re: [RE-wrenches] Small battery bank vs too large array

[Brian Teitelbaum]

Drake,

I've been hounding a couple of the charge controller manufactures about this 
issue, but so far I just haven't seen a light bulb go off in their heads, but 
I'll keep trying, and maybe this is a better forum to do it.

MPPT controllers can be adjusted to current limit at amperage values below 
their rating, but if you do that, you are also limiting the output of the array 
in general, and the amount of PV power available to run the loads directly from 
the array (through the inverter). Not the best use of available PV power.

Say you have an 80A controller and a 200AH battery. With current technology, 
you have two choices:

Let the controller operate at 80A. If you have loads to draw off some of the 
current (or sell to the grid), great, but if not you could be seeing a charge 
rate of C/2.5, which would be pretty hard on a sealed 200AH battery, to say the 
least. Granted, the battery voltage would rise pretty quickly, and the 
controller would start to taper off, but it would still see high currents 
especially if the absorption time is set long. Not a happy scenario.

Or, you can set the current limiting on the controller to 20A for a C/10 charge 
rate. But if you had loads drawing 60A, you would be pulling that additional 
40A from the battery and not using the array's full power. Also not a happy 
scenario.

What we need is a controller that can read the signal from a shunt at the 
battery, and use that as the basis of current limiting control.

For example, if we have an array that can produce 80A of current, but we want 
to limit the battery to 20A of charge, there would be 60A of potential current 
there to run loads without drawing on the battery. If there are no loads 
running, the controller should current limit at 20A (reading from a shunt), but 
if loads are turned on, the controller should be able to let more current 
through while still limiting the battery to 20A. When loads are shut off, the 
controller should go back to a 20A limit.

This doesn't all have to happen very quickly as a battery can take a heavier 
charge for a short period of time, but I think that this would be a major 
improvement of controller function.

Of course, if you are grid-tied you can sell all the excess power, but if the 
grid goes down, or you are off-grid?

Because of the low cost of PV and the high cost of batteries these days, I'm 
seeing more and more requests for large arrays with smaller batteries. I also 
think that PV is now cheap enough to allow for oversizing of arrays for better 
battery charging on cloudy days, which can reduce generator run times. We need 
smarter controllers.

What say ye, charge controller gurus?

Brian Teitelbaum
AEE Solar

From: re-wrenches-boun...@lists.re-wrenches.org 
[mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Drake
Sent: Thursday, July 19, 2012 2:21 PM
To: RE-wrenches
Subject: [RE-wrenches] Small battery bank vs too large array

Hello Wrenches,

Where can I get a device that will measure current through a shunt and create a 
signal to trigger a relay?

We want to be able to use a 2 kW array with four, 200 AH sealed batteries on an 
Outback system.  2 kW of PV would be too much amperage for the batteries.  The 
idea is to open relays to disengage strings in conditions of high current to 
the batteries.

The reason for this is to create backup systems where power will be abundantly 
available when the sun shines. The system will normally connect to the grid, 
except during outages.  In normal charging conditions the power will go 
straight to the grid.  When the grid is down, power will be available for loads 
and battery charging, but batteries will be protected from overcharge?

Any suggestions on ways to accomplish this are welcome!

Thanks

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] mounting hardware and U.L.

[Jay Peltz]

Is unistrut UL?

Kay

Peltz power

Sent from my iPhone

On Jul 19, 2012, at 6:36 PM, "Marco Mangelsdorf"  wrote:

> Does anyone know whether there are U.L. standards when it comes to PV 
> mounting hardware?
>  
> That is, are there any mounting hardware manufacturers (UniRac, Professional 
> Solar Products, DPW, Schletter) who have achieved U.L. listing/approval for 
> their stuff?
>  
> After using PSP for the past 12 years here on the Big Island of Hawaii, now, 
> all of a sudden the new building division head is taking an interest as to 
> whether PSP hardware is U.L. something or other.
>  
> So very frustrating
>  
> Thanks,
> marco
>  
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Re: [RE-wrenches] mounting hardware and U.L.

[Jason Szumlanski]

See UL 467 for grounding clips. See
http://www.bizjournals.com/prnewswire/press_releases/2012/07/09/NY36598 for
other standards.

I've never been asked about listings for mounting systems except the UL 467
listing for bonding the rails using listed devices.

Jason Szumlanski
Fafco Solar


On Thu, Jul 19, 2012 at 6:36 PM, Marco Mangelsdorf wrote:

>  Does anyone know whether there are U.L. standards when it comes to PV
> mounting hardware?
>
> ** **
>
> That is, are there any mounting hardware manufacturers (UniRac,
> Professional Solar Products, DPW, Schletter) who have achieved U.L.
> listing/approval for their stuff?
>
> ** **
>
> After using PSP for the past 12 years here on the Big Island of Hawaii,
> now, all of a sudden the new building division head is taking an interest
> as to whether PSP hardware is U.L. something or other.
>
> ** **
>
> So very frustrating
>
> ** **
>
> Thanks,
>
> marco
>
> ** **
>
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[RE-wrenches] mounting hardware and U.L.

[Marco Mangelsdorf]

Does anyone know whether there are U.L. standards when it comes to PV
mounting hardware?

 

That is, are there any mounting hardware manufacturers (UniRac, Professional
Solar Products, DPW, Schletter) who have achieved U.L. listing/approval for
their stuff?

 

After using PSP for the past 12 years here on the Big Island of Hawaii, now,
all of a sudden the new building division head is taking an interest as to
whether PSP hardware is U.L. something or other.

 

So very frustrating

 

Thanks,

marco

 

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[RE-wrenches] Array direct farm machinery?

[Eric Youngren]

Howdy Wrenches,

We are thinking up new ideas for powering agriculture in the rural
developing world to propose for the new USAID "Energy Grand Challenge for
Development" 

One idea is to build PV array direct water pumping systems for irrigation
that could be converted to power productive use farm machinery for grain
milling, oil pressing or other farm processing jobs after the harvest is
in.  The idea being that after the harvest they don't need the irrigation
pumping for a bit and the PV array could be switched over to drive a motor
to accomplish a mechanical task.  For that matter if it was an easy swap
(Anderson 2 pole connectors, dual battery boat switches, etc) between the
pumping load and the machinery load the same PV array could be used on any
given day to either run the pump or the machine(s). I'd like to avoid
batteries altogether and I'd like to allow a single 1 to 3 kW PV array to
accomplish multiple array direct mechanical tasks.

This is just a brainstorm at this point,  maybe this is a crazy idea and
not worth pursuing, but I'd be really curious if anybody has any experience
doing anything like this or any other ideas to bring to the table.

Any ideas?  Thanks!

Eric Youngren
Solar Nexus International
www.solarnexusinternational.com
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Re: [RE-wrenches] Small battery bank vs too large array

[Jason Szumlanski]

I could be wrong, but I thought the FM60 and FM80 charge controllers have
adjustable current limits that apply to battery charging, and I think when
integrated with GVFX inverters in sell mode and a Mate controller, you will
be able to accomplish what you need to do without a relay. I always thought
when the charge controller indicated GT Mode and was in bulk charging mode
that the current limit would be essentially ignored because the battery
voltage is above the sell voltage and any available DC current would be
inverted and sold to the grid. In other words, the batteries are full, so
they are not being charged - the FM60 and GVFX communicate and balance the
current available for selling.

You may want to talk to Outback about that, because I don't think it is
documented all that well, and again, I could be wrong. I've never installed
that much solar on a small battery, so it never came up! Incidentally, I
have someone that came in today looking for a 5kW grid-interactive system
and a small battery to handle critical loads. I was leaning to an AC
coupled system to get away from the issue you describe, but now I am
second-guessing that theory. I'd be interested to learn what you discover.

Most inverter manufacturer's have a minimum battery size, but that
seemingly is there to address the maximum possible current out of the
battery, not the charging rate because that can be limited, too.

Jason Szumlanski
Fafco Solar


On Thu, Jul 19, 2012 at 5:20 PM, Drake  wrote:

>  Hello Wrenches,
>
> Where can I get a device that will measure current through a shunt and
> create a signal to trigger a relay?
>
> We want to be able to use a 2 kW array with four, 200 AH sealed batteries
> on an Outback system.  2 kW of PV would be too much amperage for the
> batteries.  The idea is to open relays to disengage strings in conditions
> of high current to the batteries.
>
> The reason for this is to create backup systems where power will be
> abundantly available when the sun shines. The system will normally connect
> to the grid, except during outages.  In normal charging conditions the
> power will go straight to the grid.  When the grid is down, power will be
> available for loads and battery charging, but batteries will be protected
> from overcharge?
>
> Any suggestions on ways to accomplish this are welcome!
>
> Thanks
>
> 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-wrenches] Small battery bank vs too large array

[Drake]

Hello Wrenches,

Where can I get a device that will measure current through a shunt 
and create a signal to trigger a relay?


We want to be able to use a 2 kW array with four, 200 AH sealed 
batteries on an Outback system.  2 kW of PV would be too much 
amperage for the batteries.  The idea is to open relays to disengage 
strings in conditions of high current to the batteries.


The reason for this is to create backup systems where power will be 
abundantly available when the sun shines. The system will normally 
connect to the grid, except during outages.  In normal charging 
conditions the power will go straight to the grid.  When the grid is 
down, power will be available for loads and battery charging, but 
batteries will be protected from overcharge?


Any suggestions on ways to accomplish this are welcome!

Thanks

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] roof attachment in tile roof

[Dave Click]

As a note for tile roofs: the tile keeps most of the water on top of it 
but it's not the actual sealed layer. The underlayment is the true 
waterproofing layer, so be sure you seal the penetration through the 
underlayment as well as the hole you cut in the tile.



On 2012/7/18 23:42, Parrish, Peter wrote:

That's the link. Yes, that is the big advantage IMHO. If you use a 7/16
masonry drill (as I remember) there is scant clearance between the
resultant hole and the 3/8" SS all thread. I use a liberal amount of
Sika 1A caulk around the annular ring and regular SS 3/8" washer on top
of that. In southern California we have lots of flat concrete tiles
(even easier) as well as S-tiles. I think there still is an app note on
their website. Keep the bit cool by dunking it in a cup of water between
holes.

- Peter

*From:* re-wrenches-boun...@lists.re-wrenches.org
[re-wrenches-boun...@lists.re-wrenches.org] on behalf of benn kilburn
[b...@daystarsolar.ca]
*Sent:* Wednesday, July 18, 2012 4:48 PM
*To:* RE-wrenches
*Subject:* Re: [RE-wrenches] roof attachment in tile roof

Peter,
Do you have a link to the tile track you referred to.  Is it the one
spelled Tile "Trac" found at this link >> TileTrac

This is nice as it has the flexibility to locate the bolt at the top of
the tile when the rafter doesn't line up. But it relies on the bolt
going thru the tile at the high point (and some sealant) for keeping
water out?
Benn

DayStar Renewable Energy Inc.
www.daystarsolar.ca  *  Ph: 780-906-7807
Construction Electrician Solar Photovoltaic Systems Certified
Certificate # 0007S
HAVE A SUNNY DAY

On 18/07/12 2:44 PM, "Parrish, Peter" mailto:peter.parr...@canyons.edu>> wrote:

All the hooks I have tried caused the tile to “pop up” and to avoid this
one has to notch the tile. More trouble than it is worth IMHO. Tile
track works well and doesn’t need flashing.

Peter Parrish

College of the Canyons

peter.parr...@canyons.edu 

O: (661) 362-3888 C: (323) 839-6108

-

*From:*re-wrenches-boun...@lists.re-wrenches.org

[mailto:re-wrenches-boun...@lists.re-wrenches.org] *On Behalf Of *Benn
At DayStarSolar
*Sent:* Wednesday, July 18, 2012 8:38 AM
*To:* RE-wrenches
*Subject:* Re: [RE-wrenches] roof attachment in tile roof

William, Jason;

I appreciate the suggestion, it sounds like an ideal solution.

  I do wonder why you prefer posts when you could use the tile hooks and
avoid the extra work and time of cutting and flashing? If it makes for a
better attachment structurally and weather-proof wise, then I'm all for it.

Could you make a few points for/against tile hooks vs flashed posts?


Thanks.

benn

Sent from a 'smart' phone, with tiny keys. Please excuse shortcuts and
typos.


On 2012-07-13, at 2:20 PM, Jason Szumlanski mailto:ja...@fafcosolar.com>> wrote:

I should have mentioned that a few manufacturers make complete
standoff and flashing systems:

http://www.quickmountpv.com/products/universal-tile-mount.html#page=overview

http://www.verde-industries.com/solar-flashings/solar-flashings.html

There are others.


Jason Szumlanski

Fafco Solar

On Fri, Jul 13, 2012 at 4:12 PM, Jason Szumlanski
mailto:ja...@fafcosolar.com>> wrote:

Agreed. AKA Stand-offs. Unirac makes two-piece standoffs in 4-7".
Two lags per base make a highly secure connection to the truss.

NRCA Flashing detail

http://www.nrca.net/consumer/types/details/tile-7.pdf


Jason Szumlanski

Fafco Solar



On Fri, Jul 13, 2012 at 2:18 PM, William Miller
mailto:will...@millersolar.com>> wrote:

Benn:

None of the below.  Use stanchions, also known as power posts.
  Flash them properly, just like a roof vent, only they will be
perpindicular to the roof surface, not vertical.

William Miller



At 06:40 AM 7/13/2012, benn kilburn wrote:

Hanger bolts or tile hooks….What does the collective wisdom of this
list have to suggest/recommend?

Cheers,
Benn

DayStar Renewable Energy Inc.

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Re: [RE-wrenches] roof attachment in tile roof

[Parrish, Peter]

That's the link. Yes, that is the big advantage IMHO. If you use a 7/16 masonry 
drill (as I remember) there is scant clearance between the resultant hole and 
the 3/8" SS all thread. I use a liberal amount of Sika 1A caulk around the 
annular ring and regular SS 3/8" washer on top of that. In southern California 
we have lots of flat concrete tiles (even easier) as well as S-tiles. I think 
there still is an app note on their website. Keep the bit cool by dunking it in 
a cup of water between holes.

- Peter

From: re-wrenches-boun...@lists.re-wrenches.org 
[re-wrenches-boun...@lists.re-wrenches.org] on behalf of benn kilburn 
[b...@daystarsolar.ca]
Sent: Wednesday, July 18, 2012 4:48 PM
To: RE-wrenches
Subject: Re: [RE-wrenches] roof attachment in tile roof

Peter,
Do you have a link to the tile track you referred to.  Is it the one spelled 
Tile "Trac" found at this link >> 
TileTrac
This is nice as it has the flexibility to locate the bolt at the top of the 
tile when the rafter doesn't line up. But it relies on the bolt going thru the 
tile at the high point (and some sealant) for keeping water out?
Benn

DayStar Renewable Energy Inc.
www.daystarsolar.ca  *  Ph: 780-906-7807
Construction Electrician Solar Photovoltaic Systems Certified
Certificate # 0007S
HAVE A SUNNY DAY

On 18/07/12 2:44 PM, "Parrish, Peter" 
mailto:peter.parr...@canyons.edu>> wrote:

All the hooks I have tried caused the tile to “pop up” and to avoid this one 
has to notch the tile. More trouble than it is worth IMHO. Tile track works 
well and doesn’t need flashing.

Peter Parrish
College of the Canyons
peter.parr...@canyons.edu
O: (661) 362-3888 C: (323) 839-6108


-

From: 
re-wrenches-boun...@lists.re-wrenches.org
 [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Benn At 
DayStarSolar
Sent: Wednesday, July 18, 2012 8:38 AM
To: RE-wrenches
Subject: Re: [RE-wrenches] roof attachment in tile roof

William, Jason;
I appreciate the suggestion, it sounds like an ideal solution.
 I do wonder why you prefer posts when you could use the tile hooks and avoid 
the extra work and time of cutting and flashing? If it makes for a better 
attachment structurally and weather-proof wise, then I'm all for it.
Could you make a few points for/against tile hooks vs flashed posts?

Thanks.
benn
Sent from a 'smart' phone, with tiny keys. Please excuse shortcuts and typos.

On 2012-07-13, at 2:20 PM, Jason Szumlanski 
mailto:ja...@fafcosolar.com>> wrote:
I should have mentioned that a few manufacturers make complete standoff and 
flashing systems:

http://www.quickmountpv.com/products/universal-tile-mount.html#page=overview
http://www.verde-industries.com/solar-flashings/solar-flashings.html

There are others.

Jason Szumlanski
Fafco Solar


On Fri, Jul 13, 2012 at 4:12 PM, Jason Szumlanski 
mailto:ja...@fafcosolar.com>> wrote:
Agreed. AKA Stand-offs. Unirac makes two-piece standoffs in 4-7". Two lags per 
base make a highly secure connection to the truss.

NRCA Flashing detail
http://www.nrca.net/consumer/types/details/tile-7.pdf

Jason Szumlanski
Fafco Solar


On Fri, Jul 13, 2012 at 2:18 PM, William Miller 
mailto:will...@millersolar.com>> wrote:
Benn:

None of the below.  Use stanchions, also known as power posts.  Flash them 
properly, just like a roof vent, only they will be perpindicular to the roof 
surface, not vertical.

William Miller


At 06:40 AM 7/13/2012, benn kilburn wrote:

Hanger bolts or tile hooks….What does the collective wisdom of this list have 
to suggest/recommend?

Cheers,
Benn

DayStar Renewable Energy Inc.

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[RE-wrenches] Grounding to Building Steel

[Allen Frishman]

Wrenchers,
I recently installed a 21KW system and grounded the roof mounted inverters to 
the steel of the building.  The inspector pointed out that the steel of the 
building needs to be grounded to the Grounding Electrode that the service is 
grounded to which in this case is the water pipe.  What size ground is needed 
from the Steel of the building to the water pipe?  Is the same size GEC run 
from the inverters sufficient or do I need to match the size of the GEC for the 
building service?
Al Frishman
AeonSolar

(917) 699-6641 - cell
(888) 460-2867
www.aeonsolar.com


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