I would highly recommend 2 6V GC2 golf cart batteries in series. Personally I like the Trojan T105, but expect to pay about $120-150 each. Costco sells a similar GC2 for about $90 and many people here swear by them. The point is, if you get the GC2s they will be true deep cycle batteries. I had a really hard time finding any 12V batteries that were true deep cycle. They do exist, but I couldn't find one locally. The vast vast majority of 12V batteries you find are marine hybrid. They are just about worthless for dry camping IMO.