Welcome to Fiberglass RV. While we specialize in trailers that have molded frame-less bodies, instead of panel on wall-frame construction like your FunFinder, the systems inside them are mostly similar.
We've taken a few trips this summer. One dry, [b]the rest with hookups.
Or should I take it to Batteries Plus and have them test it?
I would have the battery
tested. If you have a standard lead/acid wet cell battery, and don't have a "smart charger" as part of your trailer's converter
, then every time you camped with hookups, you were pumping more charge into an already charged battery, which possibly boiled all of the distilled water out of the battery. I ruined my 1st battery just this way.
Until I replace my original converter with one that includes a "Charge wizard" smart charger, I pull the main battery fuse whenever I am camping with hookups.