I have a 30ft 5th Wheel that has an Onan 3.6K LPG generator. I was parked in a remote part of Arizona this summer and we generated our own electricity and hauled our own water. I was very dissappointed to find that I could not keep two 12 volt deep cycle Marine batteries charged with the generator. it seems the generator takes more than it charges. I have a MagneTek 3240 Converter Charger. 40 Amp and maybe that is the trouble. It's not a new trailer. A 1993 model Hitchhiker. I have recently brought the trailer home and am charging with shore power. After three days of charging, I am reading 13.3 on a digital tester. The Monitor over the stove reads the battery as Good but not Full. How accurate are these monitors? I might add that both batteries were bought at Costco this summer and are brand new. Several times this summer I had to bring the batteries home to be fully charged with a automotive battery charger. The few times that I left the batteries in the trailer I disconnected the negative wire so that it wouldn't discharge while I was gone. i would appreciate any suggestions that anyone wants to give. I've been a member of this forum since I got the trailer in 1995. The members here have been a wonderful source of information for me and others.