This is what the Onan/Battery compartment of my 78\' Royale looks like now that it is done. Note, there is not an aluminum seperation plate as many others have in their coach compartments. The tray is from Duane Simmons, and I built the slide mechanism out of Western Red Cedar. It is screwed to a new 1/2\" treated plywood floorboard with SS screws. The aluminum bracket has a piece of Cedar as a spacer and is there to keep the battery tray from sliding on hard right corners. Batteries are Golf Cart batteies from NAPA. part # 8146 @ $71 each.