Jfet - 500 pounds more battery weight would, as noted earlier, place us close to pin weight and pickup rear axle loadings (and we are weight police). We have an auxiliary 50 gallon fuel tank/tool box and carry two extra 20# propane tanks and six x 6 gallon Jerrycans for boondocking and Mexican/Guatemalan (never plan to go past Tikal and the Petan region) travels.
A further advantage of LFP batteries is rapidity and efficiency of charge, it is almost linear. I had forgotten that we did charge the battery pack once from line power and that was when we were in Fort Collins (parked in our younger son's backyard) when they had the heavy rains and serious floods. Son Charlie said that the radio had sent an alert that power lines might go down and that we might all be ensconced in the 5th wheel - so we had best be at full power (we had misadvertently left the refrigerator on electric overnight and were down to 70% or down by about 3000Ah). So I hooked the 15 amp cord to the battery chargers (0.5kW and 1.0kW in parallel) and we were fully charged in two hours.
We do change the refrigerator to electrical during daylight (even though the propane use is minimal) and run it full-time on ac during summer (if we know it will not be cloudy the next day).
The cost of the batteries is rather high but we are full-timers and invariably Boondock at "dispersed camping" sites. We had planned to do the Trans-Labrador Highway this summer with about 600 km of gravel. This would have been a test for the system but other plans have taken priority so we now plan for the summer of 2015.
Reed and Elaine Cundiff
