[RE-wrenches] Canadian Solar "blemish"

[Kent Osterberg]

I agree with Allan that this looks like cracked cells. As long as the 
conductors on the top and bottom remain intact, there will be little if 
any degradation in the output. But the conductors are under more stress 
than normal and with daily thermal cycling they may break which could 
leave pieces of the cell isolated.

-- 
Kent Osterberg
Blue Mountain Solar, Inc.
www.bluemountainsolar.com



On 11/9/2011 3:02 PM, Allan Sindelar wrote:
> Daryl,
> Before offering my opinion, I'll note that it's only that, and I'd 
> hope to learn from others with more knowledge of PV cell structure 
> than I have. Given that, it appears to me that the silicon wafers that 
> make up these cells are extensively cracked. It likely will have 
> little effect on cell output, as the electrons that are knocked out of 
> their orbits by the photons of light must only move through the 
> silicon semiconductor as far as the microgrid of conducting traces 
> visible on the surface; that is, few if any need to bridge any of 
> these apparent cracks in order to reach the conductive traces.
>
> At my own off-grid home, all of my (BP85-90 W) modules are from the 
> mid-nineties. Many of the cells on about 10 of the 18 modules are 
> extensively cracked in similar ways, as they came from an abandoned 
> (good idea that didn't work out) system from a local Boys' and Girls' 
> Club. When I bought the dead system (quite cheaply), 8 out of 18 
> modules had been shattered by kids using it as a target for throwing 
> rocks. All of the intact modules have multiple cracked cells and even 
> chipped cover glass. All continue to perform after 15 years with only 
> a little more than predictable degradation.
>
> But to repeat, I'm interested in others' opinions, as I may be 
> completely off base here.
> Allan
>
> *Allan Sindelar*
> _Allan at positiveenergysolar.com_ <mailto:Allan at 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_ <http://www.positiveenergysolar.com/>
>
> *
> *
>
>
>
> On 11/9/2011 2:41 PM, penobscotsolar at midmaine.com wrote:
>> Hello all,
>>     We have a customer who has acquired, over the last ten years or so, a
>> large array with several different makes and models of panels, all
>> installed by a qualified electrician and the customer. They have done
>> an excellent job as far as self installed systems go.
>>     He just sent me a picture of one of his Canadian Solar 210's with a
>> very unusual pattern on it (actually under the glass). The panel is
>> about three years old and shows no decline in output, but he is
>> concerned with the very obvious visible pattern. I have never seen
>> anything like it.I've attached it to this email. Anyone?
>>
>> Thanks for any suggestions or ideas,
>> Daryl
>>


-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org/attachments/20111109/cba13355/attachment-0004.html>