Date:         Tue, 26 Nov 1996 18:50:23 -0800
Sender:       Vanagon Mailing List <vanagon@vanagon.com>
From:         Lawrence Johnson <ljohnson@halhinet.on.ca>
Subject:      Re: Aux Battery

Wiesner Craig wrote:
> This sounds like a great solution, but I do not understand the connections and
> how they are isolated.

If you have a Bentley Manual, turn to page 97.34a
Find the BATTERY CUT-OUT RELAY.
Find terminals 86 and 85.
These terminals are the switching side of the relay:

Therminal 86 is actually the same voltage as terminal 50 of the starter
(+12v when starting, 0v when not).
Terminal 85 is connected to the ignition key (+12v when key turned on,
0v when off).
The result is that the relay is open when starting the engine (only main
battery in the circuit) and closed when the engine is running (both
batteries are in circuit and being charged). The relay is also open when
the ignition key is off.

Terminal 30 is connected to the main battery +ve post which is connected
to the alternator. Terminal 87 is connected to the auxiliary battery's
+ve terminal. As a result, when the relay is closed (engine running)
both batteries are connected between their +ve terminals. The auxiliary
battery's -ve post is connected to the chassis ground. Therefore when
the engine is running, the auxiliary battery is charged along with the
main battery.

If you look under the driver's seat in the aux battery compartment would
will find a relay already located there. This is what I call the camper
services relay. The wires connected to terminals 86 and 85 of this relay
are the same wires you want for the aux battery relay. Just run a jumper
from one relay to the other. (some people just use this camper services
relay, but I think its safer to add a high amp relay for this job, 40
amp minimum).

I connected a 40 amp fuse to terminal 30 of the aux battery relay. On
the other side of the fuse I ran a 6 gauge wire to the +ve terminal of
the main battery.

I used a ground strap from the aux battery -ve post to the chassis post
located under the driver's seat.

>From the +ve terminal of the aux battery, I ran 6 gauge wire to a fuse
box with 6 posts.
>From each post, I fed one service in the camper area. However, I left
the fridge on the original camper relay. I did this so that when the
fridge is set to 12V it will switch off when the ignition key is off and
on when the engine is running. This way I cannot accidentally drain a
battery by forgetting to turn the fridge off or over to propane when the
engine is not running.

The 6 post fuse box, the 32 amp-hr aux battery, the aux battery relay
and the camper service relay all fit into the aux battery box
behing/under the driver's seat.

Have fun and remember to disconnect the +ve post of the main battery
when you are making any of these additions/changes.

Power to the web ..........
Larry
'86 Syncro Westy (and PROPEX ready)