At 06:01 PM 9/20/2003 -0700, you wrote:

>http://rodo.shacknet.nu/pix/2003_09_20/118_1867.jpg
>http://rodo.shacknet.nu/pix/2003_09_20/118_1870.jpg
><snip>

It's a battery isolator. It's basically 2 large diodes,
connected anode to anode.

Typically one terminal goes to the charging system
(output of alternator), one terminal goes to the main
battery and one goes to the 2nd (house) battery.
It allows the alternator to charge BOTH batteries, but
keeps the batteries isolated from each other.

It's used in place of the "charging relay" that's
typically used in Westy's. The main problem
with the battery isolators is that they introduce an
aproximately 0.7 volt drop in the charging voltage
which is bad because the output voltage of the
Vanagon alternator borders on being to low already.

This can be cured by adding an external voltage
regulator to the stock Bosch alternator.

If you are willing to modify your alternator for a
higher charging voltage, then you should you the
battery isolator, which is superior in several ways to
using a relay.

If you don't want to mod your alternator, then use
the relay setup and remove the battery isolator...

Steve
EJ22 -> '86 Westy "Escape Pod"