:h this is for the TT group. i have been looking to add an extra battery bank to the tub. when we purchased it. it had already been converted from a single 12 to dual 6. yea i know we haven't even ...
If, and that is a big if, you have the weight capacity on the tongue, just weld a carrier to hold two batteries over the two now on the tongue. Batteries outside a living space are always better. Even AGM manufacturers specify the batteries must be vented to the outside.