# Why cant you use alternators to charge batterys in an electric vehicle to have “infinite” mileage?

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Why cant you use alternators to charge batterys in an electric vehicle to have “infinite” mileage?

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There’s a little thing called the laws of energy conservation that mean you can never get more power out of a system than you put into it. A simple (albeit not completely accurate) way to demonstrate this is to stand up, grab your shoelaces and try to lift yourself off the floor. No matter how hard you try, you can’t lift yourself and that’s because for every pound of lifting force you apply on your shoelaces, a pound of force is applied to the soles of your shoes through your feet. The same goes if you connect an alternator to an electric motor. For every watt of power you pull out of the alternator, you have to put more than a watt into the electric motor that is driving it. You have to put *more* than a watt in because nothing is 100% efficient and some of the power you put in gets wasted simply heating up the wires and overcoming the friction in the bearings. So there you have it — you can’t generate more power than it takes to turn the alternator so your idea won’t work.

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Because the alternator will require more power to make it turn than the electricity it puts out. The motor to drive the alternator will use more energy than the alternator would produce. Energy can not be gotten from no where it has to be produced. If you had a 100% efficient alternator, and a 100% efficient motor and connected them with wire that had no resistance what so ever and no loss you could get an alternator to run the motor that turns it. In real life the alternator produces electricity and heat. The wire has a small amount of resistance, and the motor takes the electricity and produces motion and heat. All of that heat is energy being lost from the system…

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Thats exactly the problem. An alternator or other type charging unit that is efficient enough and powerful enough to charge realtime and feed off itself has not been achieved. You are talking about actually harnessing the raw power of perpetual motion. The problem is the law of entropy (second law of thermal dynmics). the energy created will dissapate before harnessing enough and stepping up to use real time. It’s been tried since Tesla an eddison first started playing with the idea a long time ago. There have been some people that came really close to achieving that but it became clear that it was easier to find other foms of initial energy. Coal, Solar, Wind, Nuclear, Oil and well you get it.

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There is no free lunch, no perpetual motion machine. The batteries supply power to the electric motor, and energy is used to move the car.

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You can’t produce enough from an alternator to charge a battery that is being used to that extent…