[davepl]

The absolute first thing to check would be without the car running insert your standard old digital ammeter inline with the negative post and cable (cable off battery). Should be 0.000 A flowing. If you see any current (and everything including dome light and so on is off, as well as aftermarket stereo that might have a clock, etc) then you've got a leak somewhere.

In other matters, I've found that a shorted diode in the alternator will cause the alternator to run very hot, and when you disconnect the field wire you'll see the idle speed pick up because its not trying to generate infinite power across the short.