Rather than spending $180.00 for an Optima battery, I had this idea:

1.   From the terminals on the relay beneath the drivers seat run extensions
out of the compartment.
2.   Obtain a boat battery box and whatever size battery you need to run
your accesories for whatever time you need.
3.   Whenever you are in need of the deep-cycle you can secure it with
bungee cords and hook it up.  When you are traveling it will charge from the
alternator.  When you are not a simple solar tricle charger should suffice
in keeping it topped off.

From looking around different FLAPS and bulk discount stores, I estimate you
can do this for less than the cost of an Optima and easily have twice the
capacity.

Jason