Winterizing questions?

Grit dog wrote:
Debating whether to pull batteries and maint them inside or let the on board charger keep them charged up. I will keep ac power to the camper.

Lots of discussion on the other issues, but not much on this. If your on-board charger is a good multi-stage unit that has a proper float mode, then go ahead and use it and be done with it. But if you have a single stage converter without a float charge mode, it may tend to over charge the batteries and "boil" the water out of them, causing permanent damage. In that case, use an external battery maintainer and either remove the batteries, or leave them in place but disconnect the converter.

I've heard of people putting a timer on the converter so it only charges the batteries an hour or two a day. This is better than nothing, but can be hard to determine the best timing to use: get it wrong and you could still be over-charging the batteries, or under-charging them which would be just about as bad.

With a good float charger and reliable power, there really isn't a need to remove the batteries and take them inside unless you live in a severe climate where it's common for temperatures to get really cold for extended periods of time. A fully charged battery won't freeze until it gets below -90 F, and I doubt it gets that cold around you. ;) As the battery discharges, its freezing point rises to the point where freezing may be a valid concern (at 40% charged, it'll freeze at 16 F.) But for the life of the battery, keeping it charged is better protection than keeping it warm.

Over the winter, I keep my batteries on-board and connected, my rig plugged in, and my three-stage on-board charger turned on. My seven year old batteries are still going strong, and only need the water to be lightly topped off once a year. Works for me.