I put an optima yellow top in the middle under the hood, next to the other battery box. Fit good with battery bracket I made. I just ran power to a BIG PAC 80 RELAY, and I am able to cut the charge to it when I want to so that at night I can kill that battery good, but I don't sacrifice the original battery, so I don't get stranded. I do recomend ACI's alternator kit for $410 shipped (less than a crappy big stator kit) and its easy to install, and it puts out 55 AMPS which is more than enough to run lights and a system with one or 2 batteries cuz of the consistent charge. I still say 2 batteries is good though if you have a lot of crap going on in your rhino...... my 2 cents