Getting Batteries and Propane Off Tongue

Reasonable questions by the OP. He may not be educated in the need to have necessary tongue weight coming from a MH. If i was in your position i would just increase the bottle size of the two 20# tanks to two 30#, 40#, or 50# depending on what your desires are. That way they are out of the way and in the place least likely for catastrophic damage from a motor vehicle accident. If you were to upgrade to dual 40# tanks you would only be adding ~40lbs to your tounge weight. Pretty insignificant. As for batteries if you must relocate them, then i would suggest an outside storage compartment large enough to fit your desired amount of batteries or use multiple storage compartments. You would probably want to internally seal & insulate the compartment & install a vent in the compartment door so the off-gasing does not seep into the trailer. Unless of course you buy AGM style batteries and then the venting isn't necessary. In my situation with my trailer, i originally wanted 4 6volt batteries on the tongue with my two 30# LPG bottles. Calculating my needs it turned out only two batteries was all i needed. If i did do it, all of them would have went on the tongue as to me more tongue weight would be welcomed as im not using a low payload tow vehicle. Mount your inverter close to your batteries. Good luck.