[1Kevin]

Assume the DRL and headlights are off. How far could you nurse a bad alternator and still have the car run. I've had bad alternators before on other cars where it seemingly died with no warning. The headlights and spark must use a lot of juice but anyone know for sure? The battery is larger than your average battery too.

 

[chittychittybangbang]

Surprisingly long. Not sure which engine you have but you have to power the ECU and minor electrical components (not a lot), the fuel pump shut off solenoid, and brake lights (if you stop). If you have a PD you also have to power the fuel injector solenoids and O2 sensor. You can test the alternator by removing the alternator belt. Then use a wood or plastic dowel to jamb the alternator fins inside the alternator and turning the pulley. It should only turn one way.

 

[bill gibson]

I read about a new Benz that only charges the battery off the alternator when the car is decelerating or braking. This gives extra engine braking and no load when driving so it saves fuel. I was thinking that this has got to be hard on the battery and alternator so they must have done some redesigning. Maybe it's something that will show up on future VWs.

 

[kd7iwp]

This would definitely be an interesting thing to see. It'd be fun to hook up a switch in the car interior that would engage/disengage a clutch on the alternator, much like how the AC compressor works. Further, it would be cool to see if it were possible to install Genshocks and then remove the alternator completely. The only real electrical hogs would be lights, radio, and heated seats, defrost, etc.