I have a 2010 Cougar 276RLS with two 12 volt batteries that will discharge in two or three days if I am running the frig on gas. This is just setting with no other use such as lights, pump, slide etc...
The Dometic DM2652 has a climate control system that uses 12V DC power to run heaters on the door strip to evaporate water that condenses on the door strips. Make sure the climate control switch is turned off to reduce battery usage.