Panel Damage---cause??

[adobejoe]

Looking at buying these 300 watt panels but something went whacky. Glass is not cracked but there are these traces showing through the cells.  He says the voltage is good, but I will also check current. What would cause this?

[DamonHD]

Can't really see in those pics, but could the traces be harmless "snail trails"?

Rgds

Damon

[DanG]

Did you pop the wiring terminal cover off and look for evidence of lightning? I've seen threaded tunnels 5-7mm across blasted through panel-back box silicone encapsulation w/ diodes still good and output normal... On that panel it pushed the deep blue color into more a metallic chrome look.

Funny those patterns look to fit someones shoe size too...

[bigrockcandymountain]

I accidentally pushed on one of mine with my knee putting it up.  It looks like that.  They are snail trails. 

Those panels have a lot of them.  They would have to be pretty cheap for me to but them.  They can also be caused by wind, vibration, hail etc. 

[adobejoe]

Thanks for replies. I will likely test both voltage and current on a few and inspect a little closer. He has 21 of them, 300 watt. I may offer $25-30 each depending on what i find. They might be okay for smaller off grid apps..but I do not think I would use on a grid tied.

adobejoe

[Mary B]

Half my panels have them from high winds and hail(surprised I haven't lost a panel!). With 95mph winds once this summer, numerous t-storm winds over 65mph and now winter winds coming they take a beating...

[SparWeb]

I would check the back and see of the backing is all wrinkled up, but I believe that pattern is actually between the cells and the cover glass, not the backing layer.
If I could get a decent voltage on each of them, I would pay money for them. 
Good luck!