[Andy4639]

It depends on the battery. Another issue is how much room do you have for the batteries. 1-12 volt is less room than 2-6volts. If you have plenty of room then it want matter. If you plan to use regular car 12 volts then yes the 6 volt golf cart batteries would be a better bet. A 12 volt deep cycle marine battery would work fine also. Any of them will be fine as long as you have a good charger to keep them going.
Or
You can buy the Odyssey 12 volts Deep cycle. I have a set of 680's & 925's. Some say 12 volts (car Batteries) want work but I can assure you these do. These aren't normal 12 volt car batteries. These are the batteries all the racers are using in the drag racing cars & carts for the amp's and able to discharge more out of them without hurting the battery. They also weigh about 14 lbs.
I have 3 of my 680's in my monster cart now for all the 12 volt stuff.
These batteries get the job done but you pay more for them.