Just posted about a problem with dead trolling motor. I went and checked batteries again and the onboard charger has one of the batteries "boiling". I could hear what sounded like boiling water under the caps but nothing is spilling out. Assuming this is the battery acid. Haven't heard this before. Could that be killing my battery which in turn is leading to no power to TM?

Very well could be. Yank the battery out and have it load tested at the auto parts store.

If new style charger?? It could be malfunctioning & not going into "maintenance mode" when battery reaches full charge .

Actually opposite of new style. 3 bank charger that is about 8-9 years old. Of the three light indicators, only two are working but I figured that was just one bank indicator going out as all three batteries stay fully charged.