This worked out as expected.
The car idles at 850RPM, and the alternator pulley has a ratio of 1:3.
I used two paralleled 10Ohm, 10W resistors (total 5Ohm, 20W).
With the new mod, the field receives about 7V at full load, drawing 2.5A. That's 30% of the original power
Resting Battery Voltage: 13.2VDC (40%SoC)
Upon Starting the engine the voltage slowly ramped over a period of 2 minutes (Actually faster than with a slipping belt) until it reached 14.1V. The car electrical system alone uses 3A.
Some Load tests after the voltage reached 14.1V (Battery not fully charged):
- Interior air blower (+20A): 13.7V
- Dipped beam lights (+15A): 13.3V
So it's charging at 35A+ at idle (It was tested a couple years ago to provide about 80A @ 750RPM @ 12.5V.
Result: Cold Battery and no more belt slippage/sluggish acceleration
For alternator kill mods. rather than completely turn off the alternator, reducing the output power allows an increase in charge efficiency, with transients being delivered by the battery instead. It's more efficient than waiting for the battery to be depleted and forcing the alternator to operate at full power to top up.