[RE-wrenches] Cracking Backing on Sharp NT-175U1 Modules

[David Brearley]

FWIW: I recently saw something similar at an installation in Central Texas that uses a similar product. The cracking in the weatherproof coating was highly localized, affecting ±8 out of ±48 modules. The affected modules differed from the others only in terms of the amount of reflected light incident on the back of the devices. (A shed roof installed over an ATV was reflecting sunlight up underneath a portion of a top of pole mounted array.) While the weatherproof material showed signs of accelerated aging—perhaps due to heat effects, reflected UV effects, or both—we could not measure any difference in performance using a multimeter. However, we did not have an I-V curve tracer with us and the irradiance was relatively low while we were at the site. 

On Feb 21, 2013, at 11:11 PM, Brian Sipp wrote:

> I inherited the service work on a couple of small commercial PV systems that were installed by another company about 7 years ago.  The systems are Sharp NT-175U1 modules and Sharp JH3500U inverters.  This client has been losing inverters at a rate of one or two per year for the last couple of years.    When I was on-site yesterday, I noticed that the backing on all of the modules (there are 120 modules at this site) looks like it’s starting to shrink and crack all over.  I’ve started an inquiry with Sharp but considering their level of response to the high number of inverter failures, I figured I’d come here before they get me doing diagnostic backflips. 
>  
> To  be clear, this is the clear part of the backing I think Sharp is calling the “weatherproof coating.”  It does not seem to have affected the white EVA part of the backing.  However, the points in the EVA where these cracks run over the solder points between the cells seems to be very thin and I can see the dark color of the solder showing through more than elsewhere.  By the time I got done with my testing on specific inverter problems and noticed the panels, I didn’t have any more time to do further testing for power output of the modules/strings so I don’t have any specific test results to share.  My concern here is that this is the beginning of a bigger problem.  Has anyone else had this experience?
>  
> Brian Sipp
> First Source Solar
> www.FirstSourceSolar.com
> 530-554-1925
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