Hello,

I believe that the main issue with the alternator and regulator is that
it's done wrong on the Vanagon and a lot of other cars.  It is
convenient to locate the regulator in the alternator, but in that
position, it sets the voltage at the alternator terminals, not at the
battery terminals where it's important.  In addition, any temperature
compensation for the correct voltage to charge the battery is done by
the alternator temperature, not the battery temperature.

In the end, it probably doesn't matter that much though.

Mike