Skip to main content
Gerry | Vanagon
Checking account...
← vanagon.com home · Continue the discussion in the forum
Subject:Re: was: Overhead Westy light - aux battery wiring
From:jon
Date:Thu, 29 Jun 2006 13:41:33 -0700

And, in my case, the voltage drop problem might actually be a benefit.
Many AGM batteries only like to be charged to 13.7 Volts (the
charging system is set to 14.5(ish) volts).

Of course, installing a thicker wire is a good idea. In that case, a
large diode could be used to drop the 14.5 to the 13.7 that many AGMs
like. The standard .7 Volt drop of a common diode is close enough.

Jon
82 Diesel Westy

On Thu, 29 Jun 2006, mark drillock wrote:

> This has been talked about for years, many have tried it. The main
> weakness is that the long stock wire runs that supply +12 to the relay
> reduce the charging voltage enough that the aux battery never fully
> charges. This problem is made worse when the fridge is running on 12
> volts at the same time you are trying to charge the battery. For those
> with the stock battery under the passenger seat, the easy answer for
> this weakness is to run a wire from the main battery directly to the
> relay, instead of using the original feed wire from the dash to the relay.
>
> Mark
>
> jon wrote:
>
> >Maybe someone already said this, but I was looking in the Bentley at the
> >80-85 Westy schematic. Seems an aux. battery could be easily added:
> >
> >The Refrigerator 12-volt heater relay could be used as the battery
> >disconnect (well, if it's big enough). Simply connect the aux bat (through
> >a fuse) to terminal 30. Move the connection from terminal 87 to 30 (this
> >supplies power to the water pump, LEDs, etc) are you are almost set.
> >
> >The center light would probably need to be wired into this system, instead
> >to the door/courtest light circuit. You'd also want to wire your stereo
> >into this circuit.
> >
> >Hmmm, I've got a nice AGM battery just waiting to be wired in. Hmmm.
> >
> >Add a trickle charger for winter, and all is set.
> >
> >Thoughts?
> >
> >Jon
> >
> >
> >
> >
>