It's possible the connection was not very tight. I cleaned everything up and tightened it and there was a tiny spark, which as some have mentioned might be normal. Obviously it's right next to my propane so I don't want to take any chances. I have to unhook my connections every time we get home and take off because I have an electric dolly to move my trailer into its carport, and the dolly requires the trailer batteries for power.
I will add some vaseline as well.
The batteries are original 3 yo 6v deep cycle. The trailer stays plugged in at all times we are not camping. I never use the tiny solar panel and it's under a carport anyway.
