We remove the battery during storage and hook it up at home to a BatteryMinder 12248 for the winter. I'll also be doing that with my 4 12V Club Car batteries to.
I charge them up for a few days, let them sit idle for a day, then check the charge. Letting them sit for at least 18hrs after charging, then taking a reading gives you the real condition. Be sure not to add water until after the charge, and the idle time.
My Other House Is A '02 Jayco 31FKS Designer TT