Date:         Wed, 16 Jun 2010 11:49:49 -0700
Reply-To:     "Mike \"Rocket J Squirrel\"" <camping.elliott@GMAIL.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         "Mike \"Rocket J Squirrel\"" <camping.elliott@GMAIL.COM>
Subject:      Re: 12.2 V at rest ('85 Westy w/2.1L)
In-Reply-To:  <08ce01cb0d2b$b436b4b0$6701a8c0@PROSPERITY>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

With all due respect to Scott, who has forgotten more about Vanagons
than I will ever learn and is willing to share it all....

More/fatter wire from the alternator to the battery should not result in
higher "morning after" battery resting voltage (before starting the
engine) /unless/ the battery doesn't get a good charge while driving the
previous day.

Measuring voltage at the dash with a meter of unknown accuracy is not
very helpful unless there are no other circuits in the dash that are
drawing current. For example, with lamps on, the voltage at the dash
will be quite a bit lower than at the battery; instead, a reasonably
accurate meter connected directly to the battery terminals, as others
have suggested, is the way to go. Monitoring this voltage while driving
will show whether the battery is getting sufficiently high voltage to
put a charge into it. Dennis Hayes wrote yesterday that "13.8 volts
keeps the batteries at or just below the gassing threshold. While it
will not fully charge them it prevents damage from long trips."

In my '84, with the stock alternator > battery wire, I routinely see
13.1 to 13.5 V _at the dash_ (cigar lighter socket) and 12.5 to 12.6
volts the "morning after," and that seems to be a pretty okay normal value.

Lower than expected charging voltage at the battery when driving could
be due to heavy loads -- headlights, etc. -- all of which pull their
power through the same wire that connects the battery to the alternator
and which has to do double-duty powering those loads and charging the
battery at the same time.

Karl, you didn't write what voltage you see at the dash when driving.
You might look at that with the headlights on and off.

As for the starter, running more/fatter wire from the alternator to the
starter solenoid should not result in more juice in the starter since
the alternator isn't doing anything useful when starting; the main
current path to it comes from the battery. That's the connection that
would benefit from beefing up.

At least that's how I sees it.

--
Mike "Rocket J Squirrel" Elliott
84 Westfalia: Mellow Yellow ("The Electrical Banana")
74 Westrailia: (Ladybug Trailer company, San Juan Capistrano, Calif.)
Bend, OR
KG6RCR