I use two 6V golf cart batteries, connected in series to produce 12V, on my boat. One of the negative terminals has very bad corrosion. But only one terminal, not the other negative terminal and not the positive terminals. I would like to figure out why?
My system is closed. I have no inboard motor to ground to, and I have no other external metal on the boat at all, so I don't have any grounding other than the batteries themselves. It's an Olson 30.