Re: Dual Batteries
If you have 2 6 volt batteries, you will have them in series to provide the 12 volts the trailer needs. With 2 12v batteries, you will need to connect them in parallel, again so that you will have the 12 volts needed.
Generally, 6 volt batteries are heavier duty than 12 volt batteries. Plus, many 12 volt batteries are not optimal for RV house use because they are actually dual purpose batteries, and don't provide optimal deep cycle service. Basically, if a battery has any 'cranking' rating, it is not the best choice for a trailer. Look for one with ONLY an AMP-HOUR rating.
So 6v batteries should provide a little more power per cycle, and last a little longer than appropriate 12v batteries.
The down side of 6 volt batteries is they tend to be taller than 12 volt batteries of the same length and width, so may not fit in your battery compartment. Plus, if 1 of the 6 volt batteries dies, you are SOL. If one 12 volt battery dies and you catch it before it drags the other one down, you can limp along on the one good one.
Whatever batteries you get, for the longest life, try not to discharge them more then 50% before recharging.
