[RE-wrenches] Backsheet failure

[frenergy]

Hey folks,

             At 2 top-of-pole ~10 year old installations (each 
installation has 2 X 12 PVs)  with Mitsubishi MF-PV170EB3 PVs I have 
found now several ( ~7) backsheets that have bubbled and a couple have 
actually ruptured.  The bubbles are only about 3/8" x 3/4" in size, 
average.  Through the glass, I can see a little browning on some of 
them.  At one installation I took Voc, Vmpp, Impp of each string and 
voltages were very close but Impp on one string was .5 amp different 
string to string at same installation.

             I have contacted Mitsubishi  and Jim says he has never seen 
this before, thus my inquiry to this list.  I just happen to have the 
ONLY 7, Mitsu PVs that have ever done this? Despite this, he has sent me 
the warranty claim form.  Check out the pic.  This inspection was 
requested because output of these two systems seems about 30% low after 
accounting for age, dust, sun angle,temp, etc.

If there are any other cases like this that may be out there, I'd 
appreciate knowing about it.

Bill

Feather River Solar Electric
Bill Battagin, Owner
4291 Nelson St.
Taylorsville, CA 95983
530.284.7849
CA Lic 874049
www.frenergy.net

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