One of the guys in our club with an 8' S&S truck camper upgraded to twin 6volt batteries. He's extremely pleased with the additional reserve capacity. Bought the batteries at Baydo's. Camping World usually has a stack of these batteries. Another club member previously had a Class A motorhome with the same upgrade. He was also very happy with the results. I'm waiting on my OEM batteries to die before upgrading.
93' YJ w/factory hood