Date:         Wed, 21 Feb 2007 11:08:53 -0800
Reply-To:     Robert Keezer <warmerwagen@YAHOO.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Robert Keezer <warmerwagen@YAHOO.COM>
Subject:      Re: Aux battery tyro
In-Reply-To:  <45DC8C2F.5040701@earthlink.net>
Content-Type: text/plain; charset=iso-8859-1

The isolator or combiner , and of course the
relay combiner , are a matter of convenience
based on your view of convenience.

By "your" I'm not singling you or anyone out,out,
but the Vanagon owner in general.

Below are listed the the main advantages of the
high-amperage switch system:

1. Allows for teaming up both batteries for
charging and cranking

2. Eliminates the need to run load wires to the
AUX battery

3. Allows all power to be shut off for storage or
maintenance /repair work on vehicle whenever the
manual calls for disconnecting the battery.

4. Is relatively simple to install with a drill
and wire cutters/crimpers.

5. Allows for full battery charging output to
both batteries without modifying the alternator
regulator

In addition, most auxilliary battery systems
promoted for Vanagons locate the battery in the
spare box behind the driver. This is an akward
location in the Westfalia, and for an Optima to
be used there, generally it means cutting off the
top posts voiding the battery warranty.

This also a more difficult area to run large
amperage cables.
Keeping the spare battery in the rear places it
closer to the starter, where with the use of
battery size cables, avoids the voltage drop that
occurs with longer cable runs.

In my humble opinion, the 4-way boat switch
(other than the expensive processor-controlled
switch) , is the best choice for extended
back-country trips where ou may not see another
car for days.

I ran the isolators for years until I discovered
the switch.
Much of my installations for hire is for folks
who have the isolators.
Isolators can have the problem of sensing the
voltage level in one battery, the usually the
main battery.

As the book by Ample Power puts it , my close
paraphrase" The regulator senses the charge of
the main battery first, which tapers back the
charge, causing the auxilliary to "languish" in
an undercharged state.

If the main battery is getting all of it's
current from the alternator through standard
guage battery cables, and the aux is getting it
from skinny low -amperage small guage wiring,
that the main will charge first.

The book Living on 12 Volts With Ample Power is
written by electronics engineers.

In this book they also warn against using the
relay charging system, for us that's the popular
hella facotry dual battery relay kit.

The warning is that a surge of current from a
hevaily discharged auxilliary battery can draw
more current than the wires can handle causing a
possible fire hazard from overheating wires aas
current rushes in from the main fully charged and
charging battery.

Ample power also has another book I recommend,
called the 12 Volt Bible. You can check these out
from most libraries.

True, the isolator may be perfect for the casual
owner who rarely spends much time out on extended
-use situations. But for me, if I am going to use
an auxilliry battery, I think the switch is best.
It's the absolute necessity if you need to give
yourself a jump .

Robert

1982 Westfalia

















--- Mark Drillock <drillock@earthlink.net> wrote:

> The voltage dropping Isolator is not a
> Separator. Different products
> entirely, though the same company makes both.
> The 1315 Separator
> connects full voltage through it.
>
> The voltage loss problem you refer to does not
> apply to all isolator
> installations either. If you buy the version
> built for our Bosch
> alternators it tells how to modify the voltage
> regulator to overcome
> this drop. I don't approve of the isolators for
> this and other reasons
> but lots of people use them with good results.
>
> The battery switch method works fine for lots
> of people as well. It is
> just a more cumbersome way to do it and
> pointless for most Westy aux
> battery needs. The Separator is the most
> graceful approach, with a high
> current relay a close second at a lower cost.
>
> The marine battery switch setup you describe is
> a far more intrusive way
> to do things. Even harder on a 1986+ model.
>
> Mark
>
> Robert Keezer wrote:
>
> > Ron,
> >
> >
> > I have done several dual battery systems for
> hire
> > and the set-up of choice is a optima yellow
> or
> > blue-top for auxilliary with a 4-way marine
> type
> > high-amperage switch.
> >
> > I was heavily influence by a very readable
> book
> > called " Living on 12 Volts with ample
> power".
> >
> > The author reccommends the high-amperage
> switch
> > over the isolator, claiming the isolator
> lowers
> > the charging voltage by amost 1 Volt.
> >
> > Using a switch offers more options. You can
> > charge both batteries in tandem, or each
> > individually.
> > The swich also allows you to switch off all
> power
> > to your car when performing work, or during
> > storage, etc.
> >
> > ......................
>




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