My Beneteau came from the factory (2002) with two 6D batteries, each with an on/off switch. The previous owner wired in a 3rd battery (starting amperage type) in parallel with one of the 6Ds. There is no on/off switch for this battery. He used the same gauge wire as the rest of the battery wiring. He also connected a charge wire from the Heart 2000 inverter charger to the smaller battery. Since this battery can't be isolated from the 6D it is wired to, it really doesn't do me any good...I can't use both 6Ds on anchor and save the smaller battery for starting the engine. I'm thinking about adding another switch between the 3rd battery and it's parrallel 6D so that I can isolate it for starting the Yanmar diesel. Any body got a clue why the previous owner would have done it this way? Any advice on the switch idea?Thanks!Agaliha