Xantrex RC7 remote not reading properly

[Medic7007]

I have a 2005 Newmar dutch star with a Xantrex 2000w inverter/charger in the interior I have a RC7 remote I have noticed my batteries reading very low recently so have been charging with the generator trying to figure out what could be wrong I checked my batteries with the multi meter and they are reading 12.8 with solar charging when checking the reading in the coach I still only get 11.3 reading Where do I go to fix this problem. Note I also have a battery disconnect with a battery reading it is also reading 11.2 in any suggestions or help greatly appreciated