Date: Fri, 12 Jul 2002 14:09:58 -0600
Reply-To: "Richard A. Jones" <Jones@COLORADO.EDU>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: "Richard A. Jones" <Jones@COLORADO.EDU>
Subject: Re: Battery switches
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Someone asked about relays vs isolators at the end of June.
I posted that I had another option--a switch. Some asked
about it and I replied with what's below. I didn't post
it to the list then, but with all the questions around
Rodney's new Westy and switch, I thought I'd post it now:
............................................................
The battery switch is made by Guest (www.guestco.com) and looks
similar to their current model Cruiser 2101 ($24.95 from
www.onlinemarine.com) but mine is black and this one is
red. It is a surface mount switch rather than made to fit
on a box as some other models--at least as I understand their
web pages. It is mounted on the frig/sink/stove cabinet just
above the base of the driver seat and inboard from the
camper frig fuse (or whatever.) While driving I can
reach back below the armrest and switch it with my left hand.
Here is how it is wired: In the passenger battery compartment,
the red wire to the electrical system has been removed from
the + battery clamp and hooked to a wire to the switch. It
is tucked along the left side of the compartment and fits
there without interfering with the battery, so the whole
system could easily be abandoned. I don't know how the
wires are spliced, since it is all neatly taped up, but if
I were doing it, I'd bolt two eyes together or something so
I didn't even cut the end of the original red wire off.
That means NO mods to the VW wiring whatsoever; I like
that kind of design!
This new wire, plus its replacement from the + battery clamp
exit through a large (~1 inch) hole in the front of the
battery compartment--a vent, I assume. Under the bus, they
go across above frame members to just below the battery
switch. A similar wire from the driver compartment comes
out about there and all three go up through the metal to
the switch just above. All these holes have insulating
sleeves of some sort. That means that there is probably
only about 10 ft total of new wire.
The wire that is being switched is size 6.0 (8 AWG?) red and
goes to terminal P on the back of the fuse/relay panel.
See Bentley 97-104 (for my '87--all are similar.) This is
where the electrical system gets its juice. [In campers,
another P terminal is used to feed the frig relay with a
2.5 size red wire--Bentley 97-33b. This is the only other
P terminal use.] The new wire is grey; I assume it is of
proper size--6.0 mm crosssection or 8 AWG.
The person who did this design/installation worked here in
Boulder for NIST--the old Nat'l Bureau of Standards--so
is probably a physicist or engineer. It all appears to
have been "done right."
One thing to note: turning the switch to OFF is not the
same as removing the ground straps because the BIG red
wire (size 70 or 1 AWG) is still going to the starter, so
terminal 30 on the starter and on to the regulator is
still HOT. The ground strap on the passenger (main)
battery still has to be taken off. The switch will
isolate the driver battery when OFF.
This BIG red wire is how the battery is charged--the
alternator is "behind" the starter--see the Bentley.
That is why the switch must be in BOTH to charge the
aux battery. The main passenger battery or both
can be charged, but not just the aux battery. I
don't find that a problem. When I am on the road
going camping or between sites, I switch to BOTH and
arrive with both batteries charged. If I keep having
senior moments and forget to switch it, I will make
a reminder card that I put in front of the
speedo to help.
The battery in El Jefe was a group 41 Interstate--the
"medium" duty. I made it the aux battery and bought a
new "Magnum" Interstate for the starting battery.
A cover "plate" of a masonite-like material was made
to cover the aux battery; it is screwed down similar
to the passenger cover. I don't know what covered
that before--maybe that compartment is open at the
top?
OK, now you know all I do. If you have questions, just
ask.
Richard A. Jones
Boulder, Colorado
'81 Vanagon Mr Bus
'87 Syncro Westy El Jefe
