I’m a new owner of a beautiful 32-foot Winnebago Access, and I just removed my chassis and deep cycle batteries when I put the RV into storage for the winter. Does anyone have any recommendations ...
First, clean them. Baking soda and water and a good rinse. Second, make sure the water is up to the proper level. Even "maintenance free" battery caps can be carefully removed.
Outside is fine, even in freezing weather. It is not necessary, nor do I recommend it, to keep them on a charger 24/7. Once every week or two bring them up to 100% SOC and they will be fine.