In my motor home I have a Xantrex inverter/charger. I have a cable that comes from the positive side of the house batteries to a large fuse. On the other side of the fuse a large cable goes to the inverter/charger to the Positive terminal on the inverter, then the neg side of the inverter a large cable goes to ground. On the same terminal after the fuse that the positive terminal connects to a slightly smaller cable goes to the 12v fuse board where all the little (car) fuses are. yours may be wired the same. I am now also having about the same problem and won't take up space to explain mine. Do what I did, call Tech support at Xantrex and tell him your problem, if you have another brand, call their tech support. He told me that I have a problem with my AC board in the inverter and gave me the number of the nearest authorized repair facility. I called and am sending my unit this morning to them for a over haul. A new unit is $1,200-$1,600, cost to repair mine and refurbishing will be around $450.-$500. it is worth fixing. But call Tech support, don't throw money at something until you know it is the problem. I figured my inverter was the problem after checking and checking but wanted to make sure before I went any further. Feel free to P.M. if you want.
