Date:         Sat, 5 Sep 2009 09:34:19 +0300
Reply-To:     Janne Ruohomäki <janne.ruohomaki@GMAIL.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Janne Ruohomäki <janne.ruohomaki@GMAIL.COM>
Subject:      Re: Only 13V from Alternator
Comments: To: Steve Williams <sbw@sbw.org>
In-Reply-To:  <200909050341.n853fNa46797@sbw.org>
Content-Type: text/plain; charset=ISO-8859-1

On Sat, Sep 5, 2009 at 5:46 AM, Steve Williams<sbw@sbw.org> wrote:
> At 10:16 AM 9/4/2009, VW Doka wrote:

>> 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.

 This surely sounds like burnt diodes. I have no experience in VW
alternators, but similar thing happened to me with my old mazda 323
(mitsubishi alternator) couple of times. One time I had 2.6A current
going from the battery all the time (measured from battery connectors)
and the battery was empty after couple of days of being parked. I
think alternators in general are quite robust electrically. Bearings
may go bad, but they dont do this. Worn out collector surfaces might,
but I think you would hear it, like bearings too. Once I had probably
a blown requlator and the voltage was something like 15v. Other times
the problem has always been diodes or brushes. Never actually have I
had an alternator that didnt start working after changing requlator +
diodes + brushes. Of course that does not mean that You wont.

If the bearings in in the alternator seem solid and collector surfaces
are alright I would not toss the alternator.