[RE-wrenches] Troubleshooting Off-grid PV

[Roy Rakobitsch]

I second what David is saying. I have seen many failed KC120's as well and
they seem to fail most often at the top of the module where some
insulating tape has been used to isolate the cell interconnecting bus as
they pass over one another on their way to the j-box. There will be some
slight evidence of browning inside the lamination looking at the front top
of the module (usually but not always). Curious to see what you find.

Roy Rakobitsch
NABCEP Certified Small Wind Installer®
NABCEP Certified Solar PV Installer®
NYSERDA eligible Small Wind installer
Certified Advanced Tower Climbing, Safety & Rescue
Wind/PV Design Engineer
Windsine Inc.
631-514-4166
www.windsine.org


On Sun, May 27, 2012 7:17 pm, David Katz wrote:
> I would check each string.  I have seen many failed 120 watt Kyocera
> modules. They had a delamination problem.
> David Katz
>
> Sent from my HTC smartphone on the Now Network from Sprint!
>
>
> ----- Reply message -----
> From: "Eric Stikes" <eric at harvesthesun.com>
> To: "RE-wrenches" <re-wrenches at lists.re-wrenches.org>
> Subject: [RE-wrenches] Troubleshooting Off-grid PV
> Date: Sun, May 27, 2012 2:51 pm
>
>
>
> Hi Wrenches,
>
> I inherited an off-grid PV system that seems to be significantly under
> producing. I have:
>
> 12 KC120's (~17V 7A each) paired up 2 in series, for 6 strings terminated
> on new 15A breakers in a new Midnite combiner,
> Output of combiner passes through a 60A breaker then into a SolarBoost 50
> charge controller. An SW4024 ties in the CC, a Kohler 8.5 Gen set, and a
> Yuasa 24V battery bank.
>
> My problem is that I never see more than about 5A (displayed at charge
> controller) coming off the array, even in full sun, regardless of the
> state of charge of the batteries. I figure I should see, at least once in
> a while, closer to between 20-30A. Batteries are, admittedly, passed their
> life expectancy as the system was installed in '02 and I am sure this is
> part of the problem. I'm thinking that if the batteries are at about 1/2
> capacity (don't own a hydrometer...yet), the controller senses the
> batteries are near full SOC even at lower voltage (~24V) and is therefore
> attempting to trickle charge even in the bulk stage. Though this is not
> how the CC is supposed to function in bulk, obviously, I'm assuming the
> old batteries are altering the standard operating conditions of the
> system. I've adjusted the Bulk set point on the CC but that doesn't seem
> to make a difference.
>
> I doubt this is part of the problem but the generator is problematic as
> well (it has it's own array of maladies).
>
> Any insight is greatly appreciated. Thanks!
>
> --
> Eric Stikes
> Owner
> SunHarvest Solar
> +1 (530) 798 - 3738
> www.harvesthesun.com<http://www.harvesthesun.com/>
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