Where are you measuring the low voltage at? The voltage regulator only
trys to maintain full voltage at the alternator, where it connects. It
has no way of detecting a voltage drop all the way up front at the dash
fuse panel. You might want to look very carefully at the larger red
wires at the alternator, in the engine compartment junction box, and at
the starter motor. I have seen many Vanagons with signs of overheated
wires due to poor connections at these places. The alternator current
output goes to each of these points before following the huge starter
cable from the starter to the battery. At the battery the alternator
current next  goes to the 2 red wires that lead from the battery
compartment, one to the dash fuse panel and the other to the hidden high
speed fan relay behind the dash. Whenever the A/C is on as well as the
headlights the total current draw is a little too much for the single
red wire that carries the alternator current from the battery post to
the fuse /relay panel. This causes the voltage at the fuse panel to be
low. Measure and compare the voltage at the battery post versus where
your meter was to see if the major part of the voltage drop is before or
after the battery. Then compare to a measurement right at the alternator
under the same conditions. You will likely find that the alternator does
a pretty good job but the voltage loss occurs later down the line,
mostly in the red wire from the battery to the fuse panel and beyond.

Don't even consider increasing the output of the alternator unless you
first upgrade the wiring along the route from the alternator to the fuse
panel. VW under engineered this IMHO. I have fixed melted charging
wiring on numerous Vanagons and seen plenty more this way at junkyards.
I believe this is even one of the causes of what many here lump into
"Vanagon Syndrome" though that is really something different.

Mark

Fin Beven wrote:

>Here in SoCal during the summer, it's often a long, hot drive from LA to Bishop up Hwy 395.  North of Mojave there's a stretch where they encourage you to turn on the head-lights, even in day time.
>
>The lights, the heat, and the A/C cause my voltmeter to drop from a typical 13+ volts down to less than 12.
>
>I would have thought that the voltage regulator would compensate for this, but apparently not.
>
>Has anyone experienced this ?
>
>Has anyone experimented with upgraded alternators or more sophisticated voltage regulators ?
>
>Thanks,
>
>Fin Beven
>'90 Carat, Custom Camping Conversion
>Pasadena, CA
>
>
>