Using the unpowered wheels on a car to generate more electricity

[wastelander551]

If a car has two-wheel drive, that means that only two wheels are driven by the motor, right? The other two are just rolling along. Well, couldn't someone find a way to use the spinning motion of the undriven wheels to generate more electricity? If this is a stupid question, I apologize.

 

[Ralston18]

Not a stupid question.

However, the concept will not work via Conservation of Energy.

All that would happen is that the kinetic energy of the undriven wheels would be used to generate electricity via a generator.

Much like a waterwheel or dam turbine would do via water. Or a wind turbine that uses air to produce the necessary mechanical movements.

However turning the generator requires energy and that requirement would place more of a load on the driven wheels. And even become counter-productive due to all the additional friction involved with the undriven wheels and the generator itself.. Energy is lost as noise and heat.

Energy is neither created nor destroyed. Only transformed.

That is why you cannot connect an electric motor to a generator and then the generator to the motor. And have the pair run forever.

AKA "perpetual motion".

 

[Gam3r01]

The closest thing to that, in a functional manner, is with cars like the Prius.
Car uses electric motors or gas engine to run, but when you brake you turn some generators to get a tiny amount of power back.

Its not logical in a strictly gas powered vehicle, for the reasons above, but in a hybrid or fully electric car the regenerative braking is a nice feature, over the span of a typical trip though you only gain a handful of miles at best