Date:         Sat, 17 May 1997 01:09:12 -0400 (EDT)
Sender:       Vanagon Mailing List <vanagon@vanagon.com>
From:         DiandChris@aol.com
Subject:      Deep cycle battery installation tips

I just installed a DieHard Group 24 deep-cycle battery under the rear seat of
my 86 Camper.  I picked the '24' size because it fits the short way and
maximizes the rest of the storage under the seat.  (Most deep-cycles are at
least 8" tall and therefore will not fit under the driver's seat.)
For those of you who may want to do the same, here's how I did it:
  First off, I set up my system so the aux battery charges from my alternator
(i.e. is connected in parallel to the main battery when the ignition is on)
but discharges as a separate system.  I had to hook all the accessories I
wanted powered off the aux battery to it separately.  
  I chose to use that tiny space under the seat to put my battery cut-off
relay into.  You could use an isolator, but a continuous duty relay that is
normally open is only about $15 at an RV shop.  I HIGHLY RECOMMEND using
short-stops (thermal circuit breakers) between the aux battery and cut-off
relay, and between the accessories and the aux battery.  Also, I think
venting is a must.  If I used the aux battery while I was driving, I wouldn't
worry so much--but I will be stopped and planted anytime those gases are
building up in the battery box under the rear seat!  So I ran a 3/8" OD 1/4"
ID clear vinyl tube through a rubber grommet in the top of a battery box to a
rubber grommet in the sloping panel forming the back of the rear seat.
  So the wiring goes like this:
--8 gauge wire between the + of the main batt and one side of the cut-off
relay.  (I went out the bottom of each box and directly under the main
'space' between the front seats.  I used the existing rubber fitting to go
through on the main batt side, a rubber grommet on the the driver's seat
side.)
--8 gauge wire between the + of the aux batt and the other side of the relay.
 (With a 50Amp short-stop mounted inside the heater box under the back seat.
 That's where I went through the floor with a rubber grommet.  I went through
the body straight down out of the box behind the driver's seat with a
grommet, then used existing wire ties to go from front to back.)
--8 gauge wire from the aux batt side of the relay to a 30A short stop.  (I'm
back behind the driver's seat.)  This is my main power supply line.  The
other side of the short stop is where all the accessories are hooked
to--since the aux system is independent of the fuse panel this is my only
protection against a short anywhere in an accessory.
--12 gauge wire from the 30A short stop to refrigerator heater relay (mine is
under the driver's seat as well.)  The water pump, the LED water/batt meter,
and the 12V part of the fridge connect to this relay.  I took the wire that
reads continuous 12V (from the main battery), bent it aside, and used this 12
gauge wire to connect to the 30A short stop instead.  Not only will the sink
pump, but the meter will measure your aux battery.  (Since the batteries are
connected together when the ignition is on, the alternator will power the 12V
part of the fridge as usual.)
--12 gauge wire from the 30A short stop out the hole by the seatbelt under
the carpet up to the dash to power the cassette player and the cig lighter.
 I don't smoke, but use the power outlet a lot.  I disconnected the 2 items
from the main power source (fuse panel) and connected them to this supply
line instead.
--16 gauge wire from a 12V supply when the ignition is on back to the cut-off
relay coil.  I found a black and yellow striped wire that supplied 12V only
when the key was in the on position and connected the 16 gauge wire to it.
 This wire activates the relay when the ignition is on, or in other words
connects the aux battery to the main battery and enables the aux battery to
be charged by the alternator.  When I shut the van off, the relay disconnects
and my aux system is completely separated from the main electrical system.
--Reg black battery cable between the - of the aux battery and the metal back
of the space under the rear seat.  Ground should be secure.
--The only other 'accessory' is the rear light.  I bypassed the supply to it
by taking off the shelf over the stove and running a wire down to post behind
the driver's seat down into the space under the driver's seat.  (Where my
'circuit-breaker protected aux power supply' is.)
  If you do all this, you get peace of mind knowing that you can play the
cassette until it stops and still jump into the driver's seat, put the key in
and start your trusty VW camper!  If you have any questions, or want some
more details, send me a direct email!
Chris Hutchinson
86 Westphalia Vanagon GL

P.S.  I also put in a DieHard replacement for the main battery--works and
fits great!