If even a small section of a photovoltaic panel is shaded for example by the branch of a tree there is a very significant drop in power output from the panel.
Burn marks on solar panels.
This is a sign of a burnt terminal.
This is because a pv solar panel is made up of a string of individual solar cells connected in series with one another.
These have been seen on panels manufactured by smaller suppliers and large distributors alike.
Just like a car battery solar panel system battery terminals can burn out.
When you use a charge controller that is what it is doing anytime the battery bank is full tapering off the.
You will need to replace all metal parts in the terminal.
Mark having solar panels in the sun without a load on them should not damage them.
The current output from the whole panel is limited to that passing through the weakest link cell.
As a result the voltage can rise which leads to a hotspot in the soldered points and or a cell.
If you work in the solar panel installation business long enough you ll inevitably come across solar panels with strange brown spots.
A burnt terminal can be cause by wiring too many panels to one terminal.
Badly soldered connections cause low resistance in the part of the panel that receives the power generated by the cell.
When you examine the terminal you will more than likely find signs of oxidation.