I'm a new Westy owner and I would like to add a house battery. It appears that there never was one as there are no cables and no holes in the box under the driver seat. This may sound like a dumb question, but if I install a deep cycle battery and connect it to the starting battery with an isolator will I be able to run my lights and fridge off that battery with out doing any other kind of wiring? (Of course, I will be running wire to the alternator so it charges when the engine is running.)