[soybean (R.I.P.)]

For a high amp. draw like you are having (28 amps) you need to have the bat. wire from the alternator wired directly to the battery terminal (10 gauge) and not through the amp gauge. Use a voltmeter in place of your amp gauge.
HTH

Exactly. Mine is done that way and I have yet to have my idle drop when my pusher fan comes on. I have to listen for the fan to cut on. It will cycle when the car is cut off, but no problems when the car is running. Jarrell