Just looking at the under side of one of me cheap 80w panels and I noticed what looks like burn/melt spots. Still seems to be working but how well I haven't determined yet. Anyone had similar occurençes on their solar panels?
Thanks for the heads up Ziffius, I've not had my 100w panel long, and I've only taken it off once since placing it in a temporary location while I figure out a permanent location for it. So far the panel has absolutely worked its socks off, but has not shown any signs of anything untoward happening. The wiring used from my panel to the charge regulator is larger in cross sectional area than the wires coming off the panel, and the rated output from the panel is also well within the capacity of the charge regulator. Up to now (about two months since the panel was new) I've never seen a charging rate in excess of 53 watts and this is used to charge battery's where there is a total capacity of 500 amp hours.
Just looked it up and these burns are caused by overheating spots. Caused by shading, by pass diodes needed to by pass the shaded sections. These were cheap eBay panels - I guess none or not enough bypass diodes. We suffer more shading than with household solar systems to to those stupid masts and rigging that keep getting in way😜