You can see how a relay hookup is wired at <http://www.knology.net/
~felder/Vanagons/>

This is for a Westie, but the basics are there. Thus approach used a
relay rather than a switch, but either will work.

Under the rear seat is a good (easy) place, but many have done the
under-passenger seat method.

Plenty of advice as to how to fuse in the archives.

Jim "Wide Tongue" Felder

On Aug 6, 2006, at 10:07 PM, Rob wrote:

> All this talk of using the 12v on the van got me thinking about how
> to do it? I've seen criticism but no DIY suggestions.
>
> I have no doubt that in the archives are detailed instructions on
> what to do if you want to put a second battery in your VW (not
> necessarily a Westie).
> With luck they would start at the basics like where do you put the
> 2nd battery?
> What type of switch do you need to put in to isolate the 2nd battery
> when the engine is turned off & where do you put that switch?
> What size wire should you run to the extra 12v outlets?
> Are each of these 'new' outlets fused? Is there a best central place
> to put the fuses?
>
> I know that someone has already done the engineering on this, made
> the errors, found out what works best & found the best ($$) place to
> purchase what's needed. Is there a web site out there with this? Is
> there a message # to look for in the archives? Is there a group that
> has all this in their FAQ?
>
> Can anyone help?
>
>
>
>
> Rob
> becida@comcast.net
>
> With a '91 Subaru 2.2 in an '87 Vanagon in western Washington.
>