How concerned are you about weight? How long do you want to go before plugging in or running the genset? Golf cart batteries will give you the best bang for the buck, but are very heavy. You would need 4 6V batteries. I had this set-up on my boat and could go 4 days without running the genset. Had a 12 volt refrig and the normal lights. I think I will spring for the Optima batteries in the 5er mainly to save the weight. They also take up a lot less space. Make sure you put in a battery switch.