Winter Battery Storage

Left my motorhome and toad in anchorage for four winters, returned each year to go again. each time all I did is fully charge all batteries and remove ground cable. All batteries still worked fine the next season

A fully charged battery has a freezing point around -80 °F while a discharged battery has a freezing point around 20 °F. By keeping the battery fully charged during the winter months, the electrolyte is less likely to freeze and cause unexpected failures.Dec 2, 2014

Since a fully charged wet RV battery freezes at -50 F, I wouldn’t worry.

rfloyd99 wrote:
I read somewhere that batteries should not be allowed to freeze.

You need to find better resources to read. As was said, fully charged batteries are fine to at least 0°F.

nickthehunter wrote:
If they are fully charged they won’t freeze at zero. As they self discharge over time while sitting there they could. A discharged battery will freeze at 20* F. A trickle charger or something similar (solar?j will help to keep the batteries fully charged.

^^^^THIS^^^^

Folks don't take batteries out of their cars for winter when not using that car for several months in the winter, why should one drag the batteries out of their RV for winter?

Fully charged batteries will not freeze even in sub freezing temps for weeks at a time.

Simply put, no need to go to the work and hassle of removing and storing the batteries inside your home, garage or basement as long as you have fully charged the battery and have disconnected the battery from the RV electrical system for the winter provided you do not have access to power while in storage.

If you have a RV with a modern multistage converter and you have power available, you can even just plug the RV in and let the converter take care of the batteries.

What you don't want to do is leave the batteries connected to your RVs electrical system without having some means of charging. The RV electrical system has 12V devices like the stereo, water heater, fridge, furnace which all draw a small amount of power even when they are turned off.. Those small draws will flatten your battery in a matter of a week or two.. Hence the need to plug RV into power or disconnect the batteries for storage.

best advice is to disconnect them, bring them into the garage and put them on a battery charger with a maintenance setting. otherwise if you must leave them in the RV be sure each cell is filled with distilled water. if your RV battery charger has a maintenance mode leave the RV plugged in. if you don’t have an electric connection you might wrap or cover them with a blanket. but if the cells are full and the batteries are fully charged you should be ok.

If they are fully charged they won’t freeze at zero. As they self discharge over time while sitting there they could. A discharged battery will freeze at 20* F. A trickle charger or something similar (solar?j will help to keep the batteries fully charged.