Make SURE you get a real deep cycle battery, not some "dual use" crap. Also, keep it charged as much as possible. Batteries like to be kept at full charge, leaving them partially charged kill 'em. Reference Maine Sail's forum here for suggestions on good batteries.I just finished charging my battery and the charger tells me that there is a problem with the battery, not sure exactly what but it gives me an alarm code, so I guess I'll have to get a new battery, solar charger will have to wait