Battery Charger Question

[Padgman]

Last year I had an issue with the batteries and thought they were old and just replaced them. The camper is always hooked to shore power when not on the road. Well the batteries went dead again. I removed the less than year old batteries, filled them with distilled water, and charged them back to 100%. When I hooked them back up I checked the voltage and I am getting 13.2 VDC using a Fluke Meter. The Positive lead from the trailer connected and the Negative lead disconnected, I checked for power from the Battery Charger and I am only getting 10.8 VDC. I am assuming this is a Battery Charger issue, but looking for advice. The rig is a 2012 Keystone Alpine. Any advice would be appreciated.