I would go with two golf cart batteries. Each battery is 6 volts so you must wire them in series, positive to negative, this will give you 12 volts. You should get close to 225 ah. These batteries are true deep cycle batteries. The lead plates inside the batteries are larger and can take many more discharges versus a standard car battery. If your read anywhere on a battery cold cranking amps or reserve hrs these batteries are not true deep cycle. Batteries called marine deep cycle are a hybrid between true deep cycle and a starting battery. The plates are larger then a car battery but smaller then a true deep cycle battery. I hope this helps. One more thing you never want to discharge a battery more then 80% if you do this will shorten the life of your batteries.