Here's a GM Techlink article with some tips:

http://www.archivedsites.com/techlink/2010/04/new-battery-electrical-drainparasitic-load-test-diagnostic-procedure.html

I've been taught that maximum parasitic current in milliamps should not exceed 1/4 of the factory battery reserve capacity number as a "rule of thumb".

If the vehicle was factory-equipped with a 100-minute RC battery, then the max parasitic current should not exceed 25mA after all modules have powered down and gone to sleep.

Dave Hobbs has a good article on parasitic drain here:

http://www.diagnosticnews.com/tech/parasitic-battery-drains/

Joe Glassford's chart for measuring parasitic drain via fuse voltage drop is here:

http://vestest.com/HowtodoParasiticdraintestacrossfuses.pdf

Michael Joachim
Owner
Mike Joachim
Pelham, Alabama, USA