A car makes more electricity then it needs. That is wasted energy. If you could recycle that surplus into fuel the argument that it would be ineficient loses its value. After all it would be free energy.. Or am i missing something.
Not to start a flame war or something, but just wondering if that would make a difference at all.
This really isn't the right place for this. Someone want to make a reddit post or something to continue this?
Cars don't make more electricity than they need. They do make more _heat_ than they need. This is why cabin heating is free and you've got a big-ass radiator on the front.
If the devices in the car are drawing 20 amps, the alternator is hard to turn, so the engine has to do work to turn it. If the devices are drawing 30 amps, the alternator is that much harder to turn, meaning the engine has to do that much more work to turn it. Engine work comes directly from fuel consumption.
I do remember reading somewhere that one of these silly devices is actually real, I think it only worked for diesel, and it provided a very small boost in fuel economy by somehow causing the engine to combust the fuel more fully, emitting less unburnt fuel in the exhaust, thereby getting more "bang for the buck". But it was nowhere near a 33% fuel-mileage gain.