Short answer: thermodynamics says you can't get more energy out than what you put in. If the batteries are moving the wheels, then any generated energy also would have to come from the batteries, making it essentially the same power as just driving the wheels.
That said, most/all electric cars do have regenerative braking (as do diesel electric trains) - meaning that if the car needs to slow down, either for a stop, or going down a hill, etc, then the car doesn't need to apply brake pads, but use the wheel "motors" as generators and charge the batteries to use up the excess speed. This process is very short term over the course of a trip, so not much is recaptured.
A good size estimate for a generator is to look at the hp of hybrids in terms of what size alternator would be needed to charge the batteries while in use.
Another issue is weight. The device in the video works because it can produce more thrust than the weight of the vehicle. Add in safety features and a driver (and 4 passengers) and the vehicle will need external power to drive it again.
The best example of a mechanical advantage system that I haven't quite run the numbers on yet is that treadmill to scooter device.
Aside from the electric assist, it does look like there may be some gearing that converts walking energy into biking energy. Bicycles themselves are around 80% more efficient than walking, so it may still be that a true bicycle outperforms the treadmill scooter in raw muscle power.
localsal 0 points 3.2 years ago
That's kind of the process that some hybrids could use - the engine runs to charge the battery and give the go juice for the wheels.
Interestingly, there is a machine that seemingly breaks the laws of physics:
https://www.youtube.com/watch?v=VUgajGv4Aok
Short answer: thermodynamics says you can't get more energy out than what you put in. If the batteries are moving the wheels, then any generated energy also would have to come from the batteries, making it essentially the same power as just driving the wheels.
That said, most/all electric cars do have regenerative braking (as do diesel electric trains) - meaning that if the car needs to slow down, either for a stop, or going down a hill, etc, then the car doesn't need to apply brake pads, but use the wheel "motors" as generators and charge the batteries to use up the excess speed. This process is very short term over the course of a trip, so not much is recaptured.
A good size estimate for a generator is to look at the hp of hybrids in terms of what size alternator would be needed to charge the batteries while in use.
Another issue is weight. The device in the video works because it can produce more thrust than the weight of the vehicle. Add in safety features and a driver (and 4 passengers) and the vehicle will need external power to drive it again.
The best example of a mechanical advantage system that I haven't quite run the numbers on yet is that treadmill to scooter device.
https://www.youtube.com/watch?v=b_L4QMOvH2o
Aside from the electric assist, it does look like there may be some gearing that converts walking energy into biking energy. Bicycles themselves are around 80% more efficient than walking, so it may still be that a true bicycle outperforms the treadmill scooter in raw muscle power.