Another Aux Battery question

[914 mike]

I purchased an 84 westy a few months back and have been busy getting it up to snuff. It has a set-up for an auxillary battery, but not the typical set up and not hooked up when I bought the van. Former owner is not around, so I am on my own trying to figure this set-up out.

Here is what I have(besides a headache trying to figure it all out):

Aux battery is located under the bed seat. Ground is grounded to the body there. and there is a positive lead that goes to the engine area and ends as a wound up bunch of wire with a circle/pole type connector on the end of the wire. Not hooked to anything. I am guessing this should go to alternator to provide the aux battery with charge?

There is a toggle switch located under the drivers seat. With the key in the off position, I switch this on and it gives power to the refrig and battery light next to the refrig light. (running off the main battery) If I turn it on when the bus is running, it activates the starter. (kinda one of those oh sh*t moments, dont want to turn that on again when the engine is running!).

I have not yet hooked up the auxillary battery. I dont know where to connect the positive wire. I dont want to fry anything...

The toggle switch seems to have the refrig wires out one side and out the other side is a small blue wire, a small red wire w/black stripe and a larger gauge all-red wire. I follow those up to the main wire mass....the big red wire goes to #7 fuse terminal, the small red w/black wire and the small blue wire go to a connector that turns into a large red wire w/black stripe and a small blue wire. The large red w/black goes out the van front firewall and I cant tell where the blue goes in all that spagetti.

So, what does it all mean? Is the solinoid being used as the relay? Will that isolate the aux battery from the main battery when I flip the toggle?

I know, get out there and start hooking thigs up and see what happens, but I am a little gun shy and dont want to fry anything. Anyone have a similar set up or have an Idea what my set up should be?
I do not have the "factory" camper relay under the seat, so I am guessing this was an attempt to achieve the same thing. I really dont want to rip it all out and start over agin if this is a viable system....

Thanks in advance,

Mike

[mog555]

No matter what the switch does and what the wires go to I would do my best to strip out the existing sytem it sounds sketchy at best. I would guess they are getting charge by hooking in at the starter and using the ignition as the relay. Strip it out, do it right, sounds like the wire is already there, may need to buy more and you have to pick up a relay at you local auto shop but what you currently have would scare me if I owned the van.
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10 Patriot
82 Westy (I-4 Digi II)

[914 mike]

Ya, I slept on it last night. I want piece of mind when i am in the middle of BFE camping and I just dont think I can achieve that with this sysytem....

Mike

[tencentlife]

The VW way to do it involved grounding the battery isolator relay coil thru the starter solenoid trigger circuit. The coil got powered by the alternator warning light wire.

There is a diode in the relay so when the starter is triggered, it doesn't backfeed the coil, so the batteries remain isolated until the alternator starts charging, when it raises the voltage on the alternator warning light wire, and that voltage excites the isolator relay coil, grounding thru the solenoid windings. There isn't enough voltage left after the coil uses the power to be able to excite the solenoid.

That way, the batteries aren't connected together until the alternator is actually charging. Kind of a clever way to do it.

Your setup may have gotten wired that way, or is an attempt at wiring it that way. If it was installed by a PO, maybe they looked in Bentley (p.97.34a) and tried to do it like the factory did, but missed the diode, so they put in a switch instead. Or the diode failed closed, and they kluged it with a switch. Who knows?

But I just wanted to point out that the way the factory did it, the starter solenoid was involved. So that may provide clues.

[914 mike]

Mine didn't have the factory relay a lot have mentioned being under the seat. Is that the relay they show on the page you mention?

Either way, I am going to rewire the whole shoot'en match just for piece of mind. I am going to add some 12v accessory plugs and a voltmeter while I am at it.

Thaks for the info....

Mike