I have a 2005 Montana Mountaineer 329RLS fifth wheel. Recently, when plugged into AC (110, 30 amp, and 50 amp), one of the two batteries gets very hot, smokes, and boils the water out. The other battery appears to not have a problem. Both are deep cycle rv/marine batteries and are connected together (wiring is correct). We spent seven weeks going to the northeast, three weeks on the Gulf coast, and two other small trips within the last nine months with no issues. Spent 10 days in south Texas when the problem started (about eight days into the trip...connected to a 50 amp outlet). Just hooked it up to our house 110 and have the same problem. The battery shows 13.78 volts when connected to the 110 (after a day of charging). When I disconnect the 110, it drops down to 12.76. It sounds like the convertor never shuts off and continues to run, even after the battery gets up to full charge. Removed the battery that smokes and checked it. It shows 12.74 volts after two hours. Is the convertor out? If so, where is it? It sounds like it is under the kitchen cabinet just behind the electrical control panel (World Friendship Co, Model WF8930/50). Appreciate any ideas. Thanks....