[Mark7]

I have used a few different methods over the years, including removing the battery and storing in my heated garage.

A few years back my onboard converter / charger started cooking the battery when left plugged in for long periods. It is built into the 120 VAC breaker panel as well as the 12 VDC fuse center as many RV's that vintage are (2004).

What I opted to do was to buy a 50 Amp smart converter / charger and I took the on board system out of the picture and wired in the new unit in a storage bay on the opposite wall of the existing setup. At the same time I wired in a 120 volt outlet on the same wall and hooked it into the "Living Room" circuit so I would have somewhere to plug the new converter in.

Not fully trusting that to maintain the battery without cooking it in my long 9 month storage time in the ND winter and spring, I bought a plug in 7 day timer and plugged the converter into it. I have it set to turn on for 3 hours, twice a week. Obviously I leave the battery connected and am not concerned about parasitic loads. Any time I need to go into the coach in the winter, the 12 volt lights work, as well as the slide pump when I have to pull in the bedroom slide which tends to creep out in the fluctuating temps a couple of times a winter.

Battery electrolyte level stays correct all winter.