I had a bad experience with two xantrex convertor/chargers, one the old original, and then the "new improved" version, both of which crapped out after intermittent issues. Different product, same manufacturer, but still. I went with a progressive dynamics unit that has been flawless. Not sure if they have the item you need or not:
RV and Motorhome Power Supplies, Converters and Centers from Progressive Dynamics
I bought my unit from:
BestConverter - Converters, Inverters, Electrical Supplies, Electronics they carry a wide variety of rv electrical and were very knowledgeable and had helpful hints for my project. I'd give them a call.