Lots of choices but it really depends on how you plan to use it, and your budget.
- A pair of 230Ah x 6vdc GC2 golf cart batteries have been the solution for about 40 years in the RV biz. They are very robust, offer useable deep cycle capacity of about 115Ah combined, and if properly maintained may last 7-8 years. They are quite heavy, require regular watering, and should be on a smart battery maintainer while in storage. Available at Wal Mart and Costco.
- A pair of 230Ah x 6vdc AGM batteries are maintenance free, offer similar useable capacity as the GC2 at 2x the price.
- A modern 12vdc lithium battery is maintenance free, light weight, offers useable capacity 2-3x the GC2 batteries for nearly the same price, and if well maintained with a smart battery maintainer with lithium charge profile may last 10 years.
After 30 years with RV ownership we added a 280Ah lithium battery and it transformed our off-grid experience. Worth a look. This is one popular choice but there are many:
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