You will need to replace all metal parts in the terminal.
Burn marks on solar panels.
A burnt terminal can be cause by wiring too many panels to one terminal.
These have been seen on panels manufactured by smaller suppliers and large distributors alike.
This is because a pv solar panel is made up of a string of individual solar cells connected in series with one another.
Hotspots on panels are mainly caused by badly soldered connections or are a result of a structural defect in the solar cells.
Mark having solar panels in the sun without a load on them should not damage them.
About half of the panels appear to have burn marks of an unknown origin.
Just like a car battery solar panel system battery terminals can burn out.
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.
The current output from the whole panel is limited to that passing through the weakest link cell.
Typically they are in the same exact place on multiple solar panels.
When you use a charge controller that is what it is doing anytime the battery bank is full tapering off the.
As a result the voltage can rise which leads to a hotspot in the soldered points and or a cell.
Badly soldered connections cause low resistance in the part of the panel that receives the power generated by the cell.