I used a ground wire that was larger than the supply wire from the relay,
and larger than the 2 wires that go from the battery to the westy fuse box.
I oriented the negative post of the battery to be near the drivers door.
then,I drilled a hole in existing sheet metal to attach the ground. The
supply currect to the battery is not governed by the ground wire(I think),
but by the supply wire size, as long as it is not smaller than the supply
wire.From the battery, 2 larger sized wires to supply the refrigerator and
other consumers exists.I also sized the ground wire at the negative post to
allow enough current to flow to these devices.My main need for going to the
auxillery battery is to power my 3 computer fans overnite.My fans seem to
run about 30 percent of the time.I thought that I may have a dead battery
any morning that I used the refrigerator. Cant sleep like that.This, even
though my radio was left on(no volume) for 20 days while the van was being
painted, and still started.I am currently trying to figure out where all
this excess refrig heat is coming from.I am getting closer to this answer
or its'solution.Using the frig on 12V didnt occur to me at the time I
bought the kit, as I never use this 12V mode.However, I may experiment with
this to save fossel fuelon a long trip now that I have this  battery. Once
again, I used a Giasson battery block to hold down the battery. For safety,
I put a non conductive cover over the positive terminal incase someone
steps on the battery cover lid and makes contact with the batttery(hot
foot!).I used a new relay because the relay that VW installed started
buzzing a year ago, and I thought that it may be fried.Also, there is no
provision for a battery vent in the battery compartment under the drivers
seat.I wanted to use my best battery for cranking, but cannot do this
because no vent exists for the weaker battery.Does anybody know how long an
auxillery battery will last ? Forever?