I looked this up while researching which way I wanted to go.. 12 Volt vs 6 Volt. If we take a look at what is probably the most common 6 volt RV battery on the market, which is the Trojan T105 (220 Ah rating) and (2) 12VDC batteries (group 27 - 220 Ah rating) both TRUE DEEP CYCLE. Originally I would have thought that there would not be much difference between the combination, only a bigger case, but I was wrong.
The T105 Deep Cycle plates and the 12 Volt battery plates are made of the same material, but the difference comes into play when you look at the thickness of the negative and positive plates of the T105 battery which are about 60% thicker than the 12 Volt counterpart. Given this information, if the batteries are properly maintained, the T105's should have a longer life cycle than the 12 Volt batteries. The length of life of these batteries is determined by how much of the material is shed from the plates, which causes the eventual failure of the batteries.
Continued in Part 2