Some interesting results: ie. High altitude BIPV suffers reduced
degradation because of minimal snow loading. (I assume because of less
flexing of the substrate?)
Array degradation was often listed as twice the module degradation.
Offering a challenge to make the installation better?
I left
http://www.sciencedaily.com/releases/2014/02/140213122404.htm
http://www.nrel.gov/docs/fy12osti/51664.pdf
go to the conclusion on page 18.
Thanks,
R.Ray Walters
CTO, Solarray, Inc
Nabcep Certified PV Installer,
Licensed Master Electrician
Solar Design Engineer
303 505-8760
On 6/1/2015 5:46 PM,
Larry,
Thanks. This is helpful. I think it's pretty clear that this system should have
been designed with at least 5 or 6 modules in series to keep the VOC higher,
but that wasn't very feasible with the original controller when the system was
installed 15 years ago. Still, it has worked pretty w
Unfortunately I don't have easy access to a Curve Tracer. That would be nice
for this situation though.
-Luke
On Jun 1, 2015, at 12:13 PM, Jerry Shafer wrote:
> Do you or anyone you know have a IR Curve tester
> Jerry
>
Luke Christy
NABCEP Certified PV Installation Professional™: Certific
HI Ray,
Can you tell me/us where you have your data on the a-Si having higher
voltage degradation over time?
thanks
jay
On Sun, May 31, 2015 at 11:31 AM, Ray Walters wrote:
> Yes, amorphous modules degrade faster then crystalline cells. 15 years
> will really start catching up with you, tha
Do you or anyone you know have a IR Curve tester
Jerry
On May 31, 2015 4:03 PM, "Randy Brooks" wrote:
> I second Jay. If one string is significantly lower, I’d check each module
> in the string. Could be a bad module.
>
> Randy
>
> On May 31, 2015, at 1:23 PM, jay peltz wrote:
>
> HI Luke,
>
>
Oooo... Or maybe a module or more are shorted and being bypassed ?
A FLIR can sometimes come in handy to look at the entire array and of course
detect bad/hot connections.
But a shorted module will be almost as hot as a working module at MPP
voltage.
boB
On 6/1/2015 11:28 AM, b...@midnit
Sorry...I meant to type 17.75V (71V).
On Jun 1, 2015, at 11:21 AM, Starlight Solar Power Systems
wrote:
Luke,
For reference, we sold/installed many hundreds of Uni-Solar products since
2002. I have never seen anywhere near that much Voc loss.
Since the PVL-68 has an open circuit of 23.1V
Partial shading will also reduce the MPP voltage and to a much smaller
extent, the Voc.
I don't suppose there are some new trees or something at the site ?
Jarmo, I like your presentation.
boB
On 6/1/2015 11:21 AM, Starlight Solar Power Systems wrote:
Luke,
For reference, we sold/instal
Luke,
For reference, we sold/installed many hundreds of Uni-Solar products since
2002. I have never seen anywhere near that much Voc loss.
Since the PVL-68 has an open circuit of 23.1V (92.4V) but you only see 14.2V
(71V), a loss of 25%, I do not believe degradation is the culprit even at 15
Thanks to everyone for your responses, both on and off-list. You guys rock.
Allan,
The system was originally installed in 2000 with an Ananda
controller/disconnect box. The giant one with the mercury relays. It failed
about 6 years ago and an MX-60 was installed to replace it. I agree that a
mo
Luke,
I deleted your first message, but I thought you wrote that the
system was pre-MPPT, with strings wired as 4 12 Vnom in series. IT
seems to me that given insufficient Vmp, a modern controller is a
no-brainer anyway, and it's only a matter to which one to use.
I agree, scratch my previous suggestion of 8 in series on the Outback
controller. I got so used to Midnites that I forgot how unforgiving
the Outback controllers are with high Voc. Run the Unisolar modules
through the Midnite sizer. http://www.midnitesolar.com/sizingTool/index.php
R.Ray Wal
Allen,
With 8 modules in series I think I'll be looking at a Classic 250 for sure to
be comfortable with winter morning VOC.
I don't really know what kind of combiner situation I'll find up in the attic.
It may be easy enough to re-wire into strings of 6 instead of strings of 8,
though that is
Jay,
the 71V I measured was the array VOC.
Accessing the wiring for individual strings is fairly difficult as the
combiners are high up in a hot attic. I didn't have a lot of time on site the
day I observed this problem, so didn't gather as much information as I could
have otherwise.
A re-wir
Jay,
Whoa, I'd be careful there. Unless there's been a change while I was
away on my bicycle, Outbacks are still 140V rated maximum voltage
and 150V hard maximum. 142Voc in May suggests that doubling strings
in series will easily exceed max Voc in winter. That's why I
One solution is to restring up to the max of the outback, say double what
you got now, easy to do on the combined. This will not change the fact of
cause that the modules are molding some of the power but will get the input
voltage up where it needs to be
Jerry
On May 31, 2015 4:03 PM, "Randy Brook
I second Jay. If one string is significantly lower, I’d check each module in
the string. Could be a bad module.
Randy
> On May 31, 2015, at 1:23 PM, jay peltz wrote:
>
> HI Luke,
>
> To add here. I'm unclear if you have measured each string or the whole array
> at 71v.
> I would check e
HI Luke,
To add here. I'm unclear if you have measured each string or the whole
array at 71v.
I would check each string for voc/isc.
And then if they are consistent, I agree that putting 2 strings in series
with a new controller might help out.
You can try it with the MX-60 as you are at only 14
esponsible Technologies for Responsible People since 1988"
P Please consider the environment before printing this email.
From: RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org] On
Behalf Of Ray Walters
Sent: Sunday, May 31, 2015 12:31 PM
To: RE-wrenches
Subject: Re: [RE-wr
Ive installed a few systems with these laminates years ago, but havent kept
up with performance much unfortunately. I have heard of the diodes going
bad (which are glued into the laminate along the sides). Maybe thats your
issue? Just speculating...
Roy Rakobitsch
NABCEP Certified Small Wind Inst
Luke,
I have never worked with Uni-Solar laminates, although I expect to for the
first time this summer, at 12,800' in the White-Inyo mountains, but that's
another story. I installed one small cabin system with US64s in 1999 (the
rancher wanted modules that would keep performing with a few vanda
Yes, amorphous modules degrade faster then crystalline cells. 15 years
will really start catching up with you, that's why we always tried to
stick to monocrystalline when we could.
I think your best option for now is to rewire the array for much higher
voltage. Even your current voltage problem
Hello Off-Grid Wrenches,
I recently made a periodic maintenance visit to a residential off-grid system I
take care of here in Southern CO, and discovered an interesting problem.
This system has an array of 48x Uni-Solar PVL-68 laminate modules applied
directly to standing-seam metal roofing.
LLC
PO Box 657
Petaluma, CA 94953
Cell: 707-321-2937
Office: 707-789-9537
Fax: 707-769-9037
From: Drake Chamberlin
To: re-wrenches@lists.re-wrenches.org
Sent: Tue, April 6, 2010 1:58:56 AM
Subject: [RE-wrenches] Voltage degradation
Esteemed Wrenches,
How much voltage overhead should we have av
.
Thank you--Darryl
--- On Fri, 4/9/10, Drake Chamberlin
wrote:
From: Drake Chamberlin
Subject: Re: [RE-wrenches] Voltage degradation
To: "RE-wrenches"
Date: Friday, April 9, 2010, 12:24 AM
What is the documentation for 10% module voltage degradation? I have heard
differen
: Drake Chamberlin
To: re-wrenches@lists.re-wrenches.org
Sent: Tue, April 6, 2010 1:58:56 AM
Subject: [RE-wrenches] Voltage degradation
Esteemed Wrenches,
How much voltage overhead should we have available on our arrays to
allow for inverters not to fall out of their DC voltage operating
range
: 707-789-9537
Fax:707-769-9037
From: Drake Chamberlin
To: re-wrenches@lists.re-wrenches.org
Sent: Tue, April 6, 2010 1:58:56 AM
Subject: [RE-wrenches] Voltage degradation
Esteemed Wrenches,
How much voltage overhead should we have available on our
HI Drake,
Its unlikely that all of the wattage degradation of the module would be in
volts only.
In conversations I've had with experts, most numbers appear to be 1/2 volts and
1/2 amps.
But if you can get your modules to get a 20% over there is no draw back except
a small % efficiency loss fr
Esteemed Wrenches,
How much voltage overhead should we have available on our arrays to
allow for inverters not to fall out of their DC voltage operating
range? Since the module power degradation is 20% over the warranty
period, I usually shoot for a module voltage that can drop 20% and
still
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