Dual Battery?

[jamanrr]

My work trips start and end with at least a 2 hour drive, and I charge the battery with a Ctek about once per month just to keep it in top shape. I may look into a smaller battery rather than the Group 31 from the Passat if mounting it under the bed. I would want to keep the bed free of permanent obstructions if possible so I could put my bike in there under the tonneau. The automatic charge relay I use can be hooked to a switch as well to combine it with the main battery when needed, so I might be able to combine in the truck battery when needed.

Is the battery in the Powerstroke F-150 bigger than a Group 65? If so maybe the tray could be modified and used to mount a second smaller battery, or two smaller batteries.

It is like two batteries in one huge lots bigger than the old optima red top I owned.