With a bit of luck, and some simple testing when choosing it, you can desulphate an ex-golfcart battery and get it back to prime condition. Keeping it that way though, will require either permanent connection to a suitable automatic charger, or regular desulphating.
Just in case anyone cares, automatic chargers are not all born equal. It's a good idea to find out far more than is on the box and the blurb, about the one you are thinking of buying before you lay down your money. I just bought one a couple of weeks ago that turns out to have a feature I didn't want - it ends every charge with an equalisation phase, which smoothly runs the terminal voltage up to 15.2 Volts over the final 90 minutes. That isn't something you'd want to do repeatedly to a sealed (i.e., Valve Regulated Lead Acid) car battery unless it was a Ca-Ca type. Lovely little charger otherwise, but not suited to a lot of people's batteries. Fortunately my almost-never-used car has a Ca-Ca battery.
