Electrical Drain Mystery

[StevenPH]

Sorry for response delay - i thought i had sent this out, but must not have confirmed the submission...

The W terminal was connected to the red wire like usual. I tested the continuity between that and the connector plug and that wire is good.

The fan was running during my readings - so my numbers include that draw unfortunately.

I'm thinking i should try to install a voltmeter in my cab, even if temporarily, to keep an eye on it during normal driving.

FYI in the pic the yellow is my jumper.

[Fatmobile]

A dash-mounted voltmeter is a great idea.
Mine has saved me several times.
I don't think your readings are that far off normal.

[greg lousy]

I agree that all your numbers are in the realm of basically charging ok. Bad exciter wire sounds pretty much established .... makes sense and is a common fail. Still think there's a good chance you were hitting enough rpms to get charging on some drives but not others... and long drives (or average drives at night) would be the only ones drawing enough to kill battery.
Once it kicks on with the rev, it will should remain charging whenever for the rest of drive.... Idling, whenever.

The questionable connection is a plastic one right under battery. Only connection between dash and alt. I think. I think there's s few wires in that terrible spot.
Of course, Any intermittent short to ground in vehicle could explain these symptoms too