I know about your battery pain. We had a Travelmaster motorhome with the house batteries on the street side mounted in a compartment about 5 feet off the ground. Had to get on a ladder just to see the top of the batteries!
It should be easy for you to tell which is which because one set should be labeled deepcycle/marine and the other starting or no label at all pther than the brand name. It would be very unusual to have more than a single large 12 volt starting battery for the engine. If anything different, I wonder if some modifications have been made from the factory setup.
Many house batteries are multiple 6 volt deep-cells for more reserve capacity. Two or even 4 are sometimes wired together, especially on rigs with lots of solar panels. Since you mention two shelves, total of 4 batteries, that makes me think all are wired together as your house battery bank.
It would certainly make it easier for you to service if the house batteries were on the lower shelf, and they even sell a metal rollout tray that might make them more assessable.
Quote:
Originally Posted by W0JON
one of the most frustrating battery issues with my 2006 Tour Master is that the battery compartment is on the street side and the batteries are on stationary shelves and you can't tell how they are hooked up or where.... to get the batteries out takes an act of God to pull the two batteries on the top up over the ledge.... the 2 batteries on the lower shelf are easy to get at (I also believe that the lower 2 batteries are the chassis (engine starting batteries I presume) the top shelf batteries appear to have multiple connections to the batteries, which I would tend to believe are the house batteries due to the multiple connections ... please verify 
Jon |