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*
[email protected]_ <mailto:[email protected]>
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, [email protected] 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
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