Dawg, we use two 6 volt golf cart batteries from Costco. They are more difficult to use but last a lot longer between charges for us. Side note, I had a Optima in my old truck for 5 years and gave it to my son when I traded it in. He got another 2 years on it and traded in his truck. I don't think the blue or yellow Optimas have the warranty length the red does.