Everything you are asking is being done all the time. There is no mystery about how to do it or what parts you need.
An alternator is an ac motor. Any motor can do both. Supply mechanical energy from electrical energy, and supply power to a battery or the grid if it is over-run.
Conversion either way incurs considerable losses.
I hope you are serious and not messing with us, as this is pretty basic stuff.
A motor driven car has no “extra” energy available to drive an alternator. Any energy used from an alternator output makes the engine or traction motor use much more energy than it produces.
Vehicles “can” and do use downhill, and braking energy to charge batteries.
Most serious forums have rules against over unity discussions, as it is a “religious” belief not founded in science.
Thank you for your replies.
I donot have a physics or engineering background and so its all a bit of a learning curve. I hope im coming from a science point of view not a religious or dream world. Im at a research and design stage logically Im trying to establish the limitations and boundaries of the concept. A motor or motors driven by the wheels to charge the batteries and to replace some of the power used.
Basics im searching for what is the smallest size motor that will achieve enough power to move a carbon fibre body and chassis not sure if a rear or front motor could achieve this, motors used in forklift trucks im pointing to.
What would the volts and amp age a motor needs to generate.