[Christ]

The way to derive a rough estimate would be to figure out the mean efficient HP rating of the engine, and the amount of fuel (BSFC chart, anyone?) that it consumes to produce that power. From that you can consider the generator to be ~ 70-75% efficient, and get a fair ballpark for about how much power it's charging the pack with.

From what I've been told, it doesn't charge the pack, though. I believe the motor is in a bypass configuration, where the power generated directly drives the car, and bleed-off power (when more is produced than necessary) feeds the pack after the fact.

IOW, from what I understand, the motor is the "middle man". More correctly, the controller is the middle man, and any excess power given to the controller is sent to the battery pack.