I have a pair of 6 volt golf cart batteries for the house and a 12 volt group 27. Last season the house bank didn't seem to be holding a charge like it should. I checked the specific gravity of the 6 volt cells before loading them onto the boat and they all read in the "fair" range. After launching I had the yard mechanic aboard checking out something else and asked if he could check the batteries too. He condemned all three. He said that I might be able to squeak out another season with these but I don't want to take the risk. They are probably 6 or 7 years old. I ordered a pair of 6 volt batteries through the boatyard. The parts guy was able to come within a few bucks of the wholesaler in Westbrook and I don't have to drive anywhere to get them. Latter on I'll pick up a group 27 at BJ's.