On some models I think they are under the floor, may have to lift out a storage box that hides them. Not sure but when I looked at some showroom models a while back I have a vague recollection of seeing them deep down a hole.
If you have a garage they could be behind a panel just as you open the O/S garage door on the right hand side behind the bulkhead. There may be a metal mesh panel which houses electrical components and the batteries may be just to the side of that. If not try the O/S storage hatch to the right of the habitation door.