>I am planning to add the second battery to my 87 westy in the near future.
> How much do I have to modify the compartment behind the driver's seat to
>accomodate the battery?
Depends on the size of the battery. I'd try real hard to find one that fits
before modifying the battery compartment.

>  Also, do you have to "tie" the battery down?
Yes, that would be a good idea. The battery could be damaged if it bounces
around. Or it could spill acid which would eventually corrode the battery
compartment.

>  I was
>hoping to be able to put the battery in a plastic marine battery case.  Has
>anyone found a decent battery that would fit in a plastic case and still fit
>in this compartment?  I do have swivel seats
I doubt that you will find a battery/case combination that will fit (height
is the main problem). Look around for a marine battery with a gelled
electrolyte. This will give you the benefit of a case as it will be
completely sealed.

>.  How much should I expect the
>dealer to charge me to set up this system?
I have no idea, but please let the list know what you find out.

  Finally, if I just put the batter
>in and the terminals touch the metal top of the compartment will I have a
>problem?
Fire, maybe explosion if the + terminal contacts the top of the compartment!

I've been thinking of adding a 2nd battery to my Westy, but it really
doesn't buy you that much unless you do some rewiring. The 2nd battery
setup is designed for Weekenders that lack propane for the fridge. Other
than the water pump for the sink, that's all the 2nd battery powers. It
doesn't power the interior lights. So you could still discharge your
primary battery with the interior lights or stereo and be unable to start
your engine. The 2nd battery is not wired such that it will start the
engine if the primary battery is dead. Of course you could use jumper
cables to do this. Other than being able to run your fridge off of 12V when
the engine is not running, I see no advantage to having a 2nd battery.

-Mark McCulley