Best way to keep chassis battery charged over winter?

I'm pretty sure your battery minder needs 120vac even if it's hard wired.

Of course it does. :h

I don't disagree that a hard wired unit is fine but it sounds like you are comparing a cheap plug in battery minder to a quality hard wired battery minder.

The five Batter Minders I had were all named brand...I got them from Amazon at (if I remember correctly) about $50 bucks each....not cheap. Fortunately, i was able to return them.

I've actually had better luck with the cheap Walmart "battery tender".