I have two grp 27 for the house, and one grp 27 for the engine and windlass. The one that wouldn't take a charge turned out to be from 2003, 7 seasons. My batteries are out of synch(not the same age) and die at random. I read that's about average. I never take them off the boat, give them a charge in the fall and again in the spring. Then they're at the mercy of the alternator and our usage.

These are lowish end deep cycle batteries from a nearby auto supply. What do others get out of their batteries?