Tom, I'm still thinking about another 68lbs. of group 27 on the tongue. On recent trip we carried a 20lb propane
tank (38 lbs. full) rather than our huge 40 pounder (69 lbs. full). Based on filled wgt. the difference of 31 lbs. would offset some of the wgt. of the second battery. I wish I had an accurate tongue wgt. but we have made a number of interior mods which added wgt. forward since I tried the plank, fulcrum and household scale method more than a yr. ago. I'm going slow on adding the additional battery for now; I have a "smart" converter to replace the Newmark whizbang in our burro
(same converter that Per Walthinson put in his) and that's first in the queue.
Denny, I'm interested in knowing how "far back" you can push those golf cart batteries before you run into trailer? Our original configuration is tank bracket forward of the battery which may be for the best but I still don't have generous room for two 27s behind the tank. I think I may have to fabricate a battery box or use two bracket mounts and make a splash cover which would only protect the fwd side of the batteries and the terminals and pigtails and jumpers and fuses on top. Does anyone know if a two-piece battery box is 1) a necessity weatherwise, 2) a necessity legality-wise?