I had an RV with two 12-volt batteries to start the engine and four 6-volt batteries for the coach, including a 1000k watt inverter/charger. Not long after buying the used coach I replaced the four 6-volt batteries. A few years later they needed replacing again, but where I was, there weren't any available. So I replaced the four six-volt batteries with three 12-volt batteries, and they seemed to work as well, long term, as the bank of 6-volt batteries.
__________________
|