Our 2007 RT 210P is virtually identical to your 2006. I agree with Deano and rowiebowie. Just make sure the battery disconnect switch is in the off position and get ready to lift those heavy batteries virtually straight up to get them out. Once out, it is a good time to check the vents Deano described and also you might want to lubricate the battery compartment slides.
Funny how they are making those batteries heavier every year. Or, do you suppose, it is just the fact that I have aged a bit in the fourteen years since we bought our 2007?