Two years ago I was in a hurry and left the battery connected when I put the camper in the storage yard. When I came back about 10 days later the battery was weak but not dead. At the end of the season I remove the battery, bring it home and connect it to a Battery Tender, If I am in a hurry I disconnect the wires, the new (2009 Alumascape) camper I just bought has a disconnect switch. A conventional charger will harm the battery if it is plugged in for a long time, a smart charge like the Battery Tender will not over charge the battery. The deep cycle batteries are designed to be able to withstand many cycles of of being completely or almost completely drained but even a battery that is designed to withstand numerious discharges that would kill a normal batter will eventually be killednfrom to many deep discharges.