You need a high end tester/charger for this.  Parts stores and Sears repair
shops will test it for free. Should have a minimum 75% output with
headlights lights and heater fan on. Alternatively, you can measure the
voltage at the alternator under this load.  Ideal output should be 14.2
volts, but 14 is typical. If 13.2 or less I consider it junk.

I've replaced two recently that tested 25% with Bosch rebuilds from my local
supplier (who could also switch the pulley for me), one of which tested at
50% when installed.  They replaced it. It's just the poor QC of rebuilds, so
test your "new" alternator too.

Stuart

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Dennis Jowell
Sent: Thursday, July 14, 2016 9:11 AM
To: vanagon@GERRY.VANAGON.COM
Subject: Checking output of alternator.

After driving my Westy to Middlebury, Vermont area decided to visit a
historical site in town. Westy started slow but it started back to the farm.
Stopped at another state park and had some lunch. Westy now won't start!!
Ugh! I used the aux battery to get it going and got home. Main battery is
new. I suspect the alternator is NG. Once again trying to understand the
Bentley test procedures on Pg. 27.18. What is " connect alternator/regulator
tester" ?? All I have is my digital ohm meter. Is that what they are saying
?

Dennis J

Dennis Jowell
Scotch Hollow Farm
Newbury, Vermont