Choosing a new house battery

My 2012 Carriage Cameo does have LED lights in one main area. The rest are halogen. The battery is not quite a year old. This problem did not occur until the Dometic 12V fridge was installed. Initially, the fridge was not working properly on the 18g wire that was in the coach for the 3 way Norcold, so I installed 10g (?) wire and it is running colder, but still on often. It seems to suck up a lot of juice. I feel that the inverter/charger just can't keep up with it and replenish the battery or keep it going on its own without a voltage drop. Yesterday, I ran the 12V with and without the converter and just on battery finding some interesting observations. I now also have a separate charger at 15A on the battery. It is hard finding a solution to something you can't see.....electricity.