So, just curious why it seems that most of the TT owners when adding batteries are sticking with 12V and not going to 6V. The longevity is longer and the performance out ways a 12V every day. typically the footprint of (2) 6V is smaller than an equally powered 12V.
It is still possible to set it up as a dual 12V battery system by putting (2) 6V in series and paralleling (2) 6V in series with the other (2) 6V in series.
If you plan on boondocking a lot 6V batteries are a better option. But they are more expensive to buy and take some modification to install. If you mostly camp with hookups a single 12V battery will serve just fine and you don't need to modify anything.
Battery - 6V vrs 12V
Linear Mode
