Ok,
That sounds like the alternator is dying.
Is it possible that you have some excessive loading that is causing the
alternator to heat up and then shut down? Is this a Vanagon or Subaru
alternator?

Dennis

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Steve Williams
Sent: Friday, September 04, 2009 10:47 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: Only 13V from Alternator

At 10:16 AM 9/4/2009, VW Doka wrote:
>Depending on the charge state of your battery, 13V is perfectly fine.

That was first thing after starting the engine in the morning, after
a night of charging from the Promariner.

400 miles later, the voltage was down to 11.6 volts at idle and at
2,000 rpm, even with the headlights off.  Not good.

>If you're recharging at night, your battery will require very little
>"topping off" after starting the engine.

Sure, but it seems just driving depletes the battery, so maybe I
should be looking at the alternator, not the regulator.