In any comparison of 6v vs 12v batteries, I think it should be mentioned for the understanding that comparing amp hours is tricky. The amp hour is not a unit of energy. Electrical energy is measured in watt hours or volt-amp-hours. So a 100 amp hours in a 6 volt battery is 6x100x1 = 600 watt hours. Compare to 100 amp hours in a 12 volt battery: 12x100x1 = 1200 watt hours. It means you need two 6 volt batteries in series to equal one 12 volt battery with the same amp hour rating to have the same energy storage.
