Life of the batteries will be best if you do what the telephone company does with theirs. Keep them inside and keep them near 76F. The oldest telecom batteries I saw were in jars that sorta looked like Lyden jars on special shelving. 30 years old.
Be careful with your batteries. They are living, breathing critters.
In the mountains, all I had was solar and batteries. 80 amps, in full sun on a cold winter day. The batteries stayed warmer than I did.
/johnny
I always chuckle when I read “Don’t charge a frozen battery”. Yeah, that’s true, but don’t let it get discharged/frozen in the first place.
One of my banks was in the water heater closet but it got kicked out. No good answer right now to the ambient storage issue except keep plenty of gas for the generators esp. in the winter. Charging the batteries will warm them but it’s hard to get enough current to do that with a bank.
It was scary the other cold morning when our power went off for just three hours or so. Stayed in bed hoping power would come back on and just when I reluctantly got up and started to get dressed, it came on. We can’t afford an automatic standby system but I was all ready in my mind what to hook up where. We have a propane fireplace for the living room so heat at least in that part of the house for a week or so would not be a problem.