I have a 1981 36 volt Club Car. I am going to install # 4 gauge cables and would like to put a couple of extra batteries in the back, with a booster switch. Do I use two 6 volt or two 12 volt batteries?
Are you talking about using the 2 12 volt batteries in parallel for 12 volts of boost? It would be the same 48 volts total with the 6 or the 12 volt batteries if you are. On the other hand 60 volts would be hard on the cart without major upgrades. I would stick with 48 volts total.