Why can't an electric car 'charge' itself?...?

Question

If in an electric car...the battery powers an electric motor and when its run down you charge it from the mains?...but why can't a high output alternator driven from the electric motor re-charge the battery whilst its running!...seems a simple answer...but,...I'm sure there must be a reason!...why electric cars dont have a high output alternator fitted?...so does anyone know it???...

Answer 1

This is actually a very simple question to answer.

The "battery" that powers an electric car is neither a conventional car battery, nor is it like a torch battery. It is a very high-powered device, which nevertheless cannot be used on its own, but has to be used in combination with others. They need far more power for a re-charge than can be produced by the vehicle in normal operation.

Let me illustrate the problem with another type of electric vehicle, common in Europe - the trolleybus. In the UK, we abandoned trolleybuses because of their inflexibility in serving new housing developments. The Dutch, in particular, have overcome this by designing a trolleybus with its own traction batteries. As the trolleybus leaves the city centre it is  powered by the overhead wires through the trolley booms. When it gets to the outskirts, where it leaves the main route to serve the housing areas, the trolley booms are lowered, allowing the trolleybus to operate around the housing using its traction batteries (much like an electric car or a conventional bus). When it gets back to the main route, the trolley booms are raised again and connected to the overhead for the trip back to the city centre. BUT, on this return journey, the trolley booms are needed to provide power to re-charge the traction batteries for the next trip.

Until we find an efficient method of parking electric vehicles at a precise spot in a docking bay to re-charge the traction batteries, we are stuck with having to plug in the vehicles by hand!



I hope this clarifies the position.

Answer 2

The only car I know that could ever charge itself was named "Christine", but she also had a really BAD atitiude as well!

Answer 3

what would normal cars do if the battery runs down and it did not have the recharge facility? Now you see the problem i am getting at, i would love it if my electric wheel chair could recharge as it is beeing used, WHY NOT YOU GUYS, COME ON BACK BE UP? love you all

Answer 4

Google "perpetual motion" and "second law of thermodynamics"  That should answer you question.

Answer 5

There are losses or inefficiencies. For example, the popular Zivan NG3 battery charger appears to be only 65% efficient, on a Power Factor meter (Kill-A-Watt).

Prevent a Zivan from killing batteries

"Prevent a Zivan from killing an electric vehicle's batteries prematurely. Old-timers will tell you this much: "Batteries don't die -- they are murdered!" .."

Answer 6

Believe it or not this has been tried many times before. Many have claimed to make a zero loss machine before but no evidence has ever been shown. Basically the problem lies in the fact that there is no machine that can turn every bit of it's energy into electrical energy. There is always a loss in the form of friction and or heat. So I spend so much energy to get the car rolling, any alternator or generator big enough to create enough energy to power that car is going to hinder the movement of the car be it through size (weight) or the torque it takes to turn the alternator. To get a car that can recharge itself, it must create the same amount of energy it uses, in other words no losses in the form of friction or heat, which is impossible with current technology. tried to make a perpetual motion machine with some big alternators in college. it ran at first then slowly the voltage started dropping because of the losses incurred in the bearings. ran a good while but eventually just stopped.

Answer 7

It  would take away too much power from the car. If the rotation of a generator did not have any resistance then you would see small windmills everywhere. There would be a dam on all fast moving streams if all it took was speed and not power. The alternator on a car takes away horsepower.The car only has one 12v battery,and recives 14amps from the alt. You would need an alt that threw over 200amps. When you look at a regular dam the generators are at the bottom of a reservoir which has thousands of pounds of pressure. The wind mill has massive blades that have a very high pitch.One of the biggest reasons we don't see electric cars everywhere is because they don't have the power and distance that a gas engine has. So if the car was too charge it self while driving it would lose a lot of power of which as of right now the MFG is not willing to take the power away to gain distance because of the consumer.

Answer 8

There is an engine that can produce more energy than it uses, the grieg water hammer invented by a couple of hick engineers can produce up to 170% of the energy that it uses, this engine has been tested and confirmed by engineers but, the scientific world denies it.

also see tessler, he invented the turbine technology used in most power station inverters and it is said that he also cracked the 100% efficiency puzzle , but then died along with his research.

either way a car would have to waste energy on movement and therefore friction and heat so its ability to conserve energy is diminished.

Discalimer : I may of dreamt all the abvove

Answer 9

you have just invented a new perpetual mobile, a machine that uses less energy than it produces, and there is a law in physics, which forbids it.

Answer 10

Conservation of energy. You lose some energy when you convert motion to electricity, and you lose some energy when you convert electricity to motion. The total amount of energy in the car can only decrease.

Unless you let it roll downhill to make the alternator charge the battery or something.

Answer 11

Ok I have a couple of simplifications.

1) Get rid of the battery and run the motor directly from the high output alternator.

2) Go the whole hog and eliminate the motor. Just run the back wheels from the movement of the front wheels. Gear up the rotation of the front wheels and drive the rear wheels. You obviously would need to push it to get it to start.

3) Weld a giant arm from the front of the car over the roof with a hand pushing the back of the car. When the front moves the back would be pushed along. I'm not sure if this one would speed up though so it may not be practical.

Answer 12

I imagine that all the energy in the electric motor is used to actaully make the vehicle move! Transferred as kinetic energy forcing against resistances such as gravity and wind. Also energy is lost through heat, depending how efficient the vehicle is.

If you had an alternator this would take engergy from the power used to move the car I would say.

Answer 13

It's technically immodest.

I suspect you spend alot of time watching monkeys at the zoo. Am I right?

.

Answer 14

That would be a perpetual motion machine. All such ideas violate the law of conservation of energy. That is the law that says energy cannot be created or destroyed, only changed from one form to another. In a battery electric car the energy is stored in the chemical bonds of the battery. When you drive the car the battery converts the chemical energy to electric energy and the motors convert the electric energy to kinetic energy (energy of motion). If you hooked a generator to the motor it would just use all the energy to run the generator to convert that kinetic energy back to electric energy, with none left over to make the car move.