Karen, I would agree with JD. It usually sits on a purpose desinged 'shelf' which is attached to the main chassis rail just behind the cab on the near-side (passenger side). If there are two batteries linked to each other then your vehicle is 24V. If it's just a single battery then it'll be 12V. You may find another batttery (possibly mounted somewhere inside the vehicle) with a split-charge system wired up so it gets charged when ever the engine is running. This second battery is the one that will power your internal lights, water and heating if you have such things fitted. (It saves the main battery from going flat so it can start the engine, etc).
HTH
Sean, April 2010
