13.5 volts at the battery is pretty typical - you'll probably get closer to
13.9 at the alternator.

Likewise 12.5 - 12.6 is what the battery carries.

Did you check the tension on the alternator belt?  I bet its slipping when
the alternator's under max load as you described.

Jake

On Tue, Dec 1, 2009 at 11:12 PM, David Cohen <Mtbdavid2@aol.com> wrote:

> Hi,
>  During the tail end of a 6 hour trip back from Turkey Day and  family
> bonding, my charging light came on.  I recently had a pretty large  car
> stereo
> amplifier and high power car stereo installed.  I also purchased  a black
> and
> decker can cooler than plugs into the lighter socket.  So, I  had my car
> stereo running, the can cooler and cell phone plugged in to the  lighter
> socket and drove this way for about 5 and half hours and then my  charging
> light
> came on.  The can cooler has a auto shutoff when sensing a  low battery
> charge.  The can cooler shut down at the same time the  dash charging light
> came
> on.   Oh, I also had turned on the  headlights for the last 2 hours of the
> drive home.
>
> I took the Vanagon into Sears today to have the battery checked and
> recharged.  It was drained downed to 9% capacity.  They recharged the
>  battery and
> did a test on the battery and said it was good.  They thought  my
> alternator might be bad but couldn't tell for sure.
>
> I then took the Vanagon to the stereo shop who installed the stereo and
> they put on volt meter on the battery.  It had 12.5V with the  engine off
> and
> 13.5V when running.  What voltage are these alternators  supposed to put
> out
> in the Vanagons?
>
> Is there anything else to check besides the battery and alternator when the
>  charging light comes on?  That is the question I was leading into.
>
> Thanks in advance,
> David
>

--
Jake

1984 Vanagon GL
1986 Westy Weekender "Dixie"

Crescent Beach, BC

www.thebassspa.com
www.crescentbeachguitar.com
http://subyjake.googlepages.com/mydixiedarlin%27