This is the second time I have had the same issue with a solar charger. The positive wire from the battery gets loose and melts part of the solar charger case.

The loose wire also causes issue with charger itself. giving it bad reading. This cause the it to think it was 100% charged and the panels didn't charge the battery. This is how we discovered it. We got a low battery warning and was like the panels should have charged things up.

So we looked at the battery bank and charger. When I looked at the charger I noticed the melted plastic. So I disconnected the solar panels and then when I went to disconnect the battery cables. I noticed the positive wire was pretty much not connecting and pretty much fell out of the hole. I had to take the cover off the controller and luckily it looks like there was just melting around the gate that is used to hold the wire in place. I was able to clean that up and get the gate working again. I think cleaned up the wires and shortened the exposed wire a little, so that none of it was extended past the wire gate. I got everything reassembled.

As of right now, everything seems to be working. I will still have to wait and see how long that lasts. I am certainly going to have to keep an eye on it.