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I am very new to this or any EV forum, so I do not know where to post this. My background in not in engineering, nor do I claim to have any working knowledge of an electronic vehicle. The following is just an idea or a more of a question that I have had for nearly 30 years. I have held a few conversations with other very normal people whom are not electrical or mechanical engineers as well. During these discussions, I was told that I should share the idea or ask the question. Like I said, this has been an idea that I have had for nearly 30 years, and with the rapid commercial expansion into the reality of electric vehicles, I find this an appropriate time to ask this without fear of wide criticism.

The alternator in a combustion engine is turned by a belt and is the electric power source of a vehicle. Obviously the power must be stored in the battery and so forth, but once the engine is started the alternator takes as the electrical power source for the vehicle and it even charges the battery. With the exception of the fuel to fire the combustion engine, the alternator powers literally everything else.

In a hybrid vehicle the batteries are recharged during the operation of the combustion engine. It is my understanding that a hybrid vehicle does not need plugged in for charging due to the combustion engine and alternator charging the batteries for use when necessary.

Long before I ever heard of a hybrid, I had the idea of using an electric engine with a couple of alternators that would be attached to the vehicles wheel assembly. using a belt system. This is much like the one in existence on a combustion engine. Once the vehicle is in motion, the belts would spin the alternators thus creating the electricity used to power the vehicle just as in the common combustion engine. All electronic features, including the engine and batteries would thus be powered by the electricity created by the motion of the vehicle.

I apologize for a long winded introduction for such a small idea, but I wanted everyone to understand that I have zero background in the area and that this was just an idea that popped into the mind of a very young man one day, and that has never gone away.

Edit: The idea came to me in 1997
 

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If the alternator was generating electricity it would produce a strong braking force on the vehicle.... much like “regenerative braking”.

If you take a small BLDC (brushless dc) motor in your hand, as long as the 3 leads coming out of the motor aren’t touching, you can turn the motor in your hand relatively freely. As soon as you touch any 2 of the leads together, it will be much harder to spin the motor with your hand. That’s because you’ve created a conductive path for the free electrons to travel in a circuit so in addition to spinning the rotor, since the magnetic fields of the rotor magnets are coupled with those free electrons you have to move the electrons as well and you can feel that in your hand as a physically resistive force on the rotor. The current of electrons ultimately converts to heat which escapes the system, or your could charge a battery or power an LED lightbulb with the current, for example.
 

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If this worked you'd have created perpetual motion.
Since that's impossible, you haven't.

Here's a 6 minute explanation worth watching covering why almost exactly what you asked isn't possible.
 

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Discussion Starter #7
I always wondered something similar if I pumped the exhaust into an engine running backwards maybe it would make petrol I could then feed into the engine or put it in another vehicle.
I understand your sarcasm. However, my idea does not include trying to re-use spent electricity.
You are proposing perpetual motion. You aren't the first by a very long way.

It won't work. That's it, finis, end, done.
How is this perpetual motion? An electric car uses battery power to start and run. The alternator in use on a combustion engine creates electricity by the spinning of the pulley, that motion is created by the combustion of the cylinders.
So instead of having the pulley attached to a combustion engine, why not have it attached the wheel base that also creates motion? Would this not allow the alternator to create energy just the same as it does on a combustion engine?
 

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So instead of having the pulley attached to a combustion engine, why not have it attached the wheel base that also creates motion? Would this not allow the alternator to create energy just the same as it does on a combustion engine?
Fundamental principles of Physics tell you that any electricity generated by your alternators (yes, they could generate power by adding "drag" to the drivetrain) would be less than the additional "drag" that they placed on the system. SO, say your alternators generate 10kW of electrical power, they would require the electric motor driving the vehicle to put more than an extra 10kW of power in to keep the speed constant.

Look up "conservation of energy" and the Laws of Thermodynamics.

The pithy version is "there's no such thing as a free lunch". If you're getting some energy out of the system, then something must be putting in more than that amount of energy for you to be able to extract it.
 

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why not have it attached the wheel base that also creates motion?
There's your fundamental mistake - it doesn't CREATE motion. The electric motor does that, by converting the electrical energy stored chemically in the vehicle's battery into kinetic energy (motion).
 

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Oh dear...we have really been here so many times.

The alternator pulley is connected to the crank pulley
the crank pulley is connected to flywheel
the flywheel is connected to the input shaft (sing along now)
the input shaft is connected to the gearbox synchros (or something)
its all connected via the gears and things
and these are all connected to the Final drive differential
The final drive differential is connected to the drive shafts...

So there is no difference where the alternator is connected its all connected and its all going round and round either driven by the engine or by the wheels.

on a slightly serious note manufacturers are now using 48V alternators which can act as motors to give an extra boost. You did say in the first post "...idea of using an electric engine with a couple of alternators that would be attached to the vehicles wheel ..... the belts would spin the alternators thus creating the electricity used to power the vehicle" This where we get the idea of perpetual motion. All EVs nowadays have one motor that does both jobs negating having two systems. I had similar ideas when I was younger. My favourite was having a big funnel on the front which caught the air and acted like a turbocharger - this wouldn't work either.

First law of thermodynamics – Energy can neither be created nor destroyed. It can only change forms. In any process, the total energy of the universe remains the same.

Basically whatever you steal from the energy associated with travelling at speed (kinetic energy) will be converted (=) to battery charge (potential energy) by slowing you down. If you don't want to slow down this equation will not be equal and some energy will have to be added this could be from a engine i.e petrol (phev) if you don't have an engine (bev) you cannot make the equation equal. Don't get me started on Toyota's "self charging hybrid" nonsense!

Thanks, I feel much better now...My wife bought me some alcohol free beer Adnams Ghost Ship - it tasted all right but is makes me go all intellectual. Sorry.
 

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why not have it attached the wheel base that also creates motion? Would this not allow the alternator to create energy just the same as it does on a combustion engine?
It's already done on electric cars... it's called regen braking. It's called regen braking because the process of generating the electricity also slows the car down.

You transfer the car's kinetic energy into electric potential energy in the battery. This process brings the car to a halt.

There's a very well known equation which limits the amount of energy which can be extracted in this manner. The upper bound is the kinetic energy of the car via KE = (1/2)MV^2 where KE is kinetic energy in joules, M is mass in kg, and V is velocity in meters per second. You will extract less energy than this because every energy conversion process has limited "efficiency" meaning some of the energy will be converted ultimately to heat rather than the intended usable energy. Different processes have different conversion factors but typical regen braking gives 70% kinetic to kinetic efficiency meaning if you regen brake a moving car, then use the stored energy to get the car moving again it will have 70% as much kinetic energy as it originally had after you brake then restart the car rolling.
 

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One interesting thing you could do is convert gravitational potential energy into kinetic energy.

You take an electric car with an empty battery at the top of a mountain... then you use regen braking the whole way down the mountain as the car moves downhill spontaneously from gravity. At the bottom you'll have a somewhat charged battery which you could then use to drive some distance over flat ground.

The equation for the upper bound of how much energy can be extracted in this manner is J = MGH where J is joules of energy, M is the mass of the car in kg, G is the acceleration of gravity in meters per second squared (9.8m/s^2), and H is the height of the mountain in meters. Because of the conversion efficiency you'll likely only get about 70% of that as usable energy on flat ground at the bottom of the mountain. Likely even less due to wind resistance, rolling resistance, etc on the way down.

You certainly won't be able to drive the car back to the top of the mountain due to conversion losses which escape the vehicle as heat.
 

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So instead of having the pulley attached to a combustion engine, why not have it attached the wheel base that also creates motion? Would this not allow the alternator to create energy just the same as it does on a combustion engine?
As far as I know all electric cars have a 12 volt battery, in addition to the main battery for vehicle motion. This 12 volt battery is necessary to run the electronics in the car, which allows the main battery to be connected to the drive system, plus many other functions such a lighting, satnav etc etc.

If it wasn't for the fact that there is an elegant and efficient electronics scheme for charging the 12 volt battery as necessary from the energy stored in the main battery, then the OP suggestion would provide an alternative method for the 12 volt charging to be achieved.
So the OPs idea is valid for creating useful energy, but not efficient for the 12 volt charging compared with the electronic scheme currently in use. Both methods derive energy from the main traction battery, but the electronics method is far more efficient.
 

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OP, take your idea to a Patent Attorney and see what he makes of it. I think the replies you have already had make that superfluous but just in case you are convinced everyone on the forum is wrong and you are a genius.......
 

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As far as I know all electric cars have a 12 volt battery, in addition to the main battery for vehicle motion. This 12 volt battery is necessary to run the electronics in the car, which allows the main battery to be connected to the drive system, plus many other functions such a lighting, satnav etc etc.

If it wasn't for the fact that there is an elegant and efficient electronics scheme for charging the 12 volt battery as necessary from the energy stored in the main battery, then the OP suggestion would provide an alternative method for the 12 volt charging to be achieved.
So the OPs idea is valid for creating useful energy, but not efficient for the 12 volt charging compared with the electronic scheme currently in use. Both methods derive energy from the main traction battery, but the electronics method is far more efficient.
No.
 

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One interesting thing you could do is convert gravitational potential energy into kinetic energy.

You take an electric car with an empty battery at the top of a mountain... then you use regen braking the whole way down the mountain as the car moves downhill spontaneously from gravity. At the bottom you'll have a somewhat charged battery which you could then use to drive some distance over flat ground.

The equation for the upper bound of how much energy can be extracted in this manner is J = MGH where J is joules of energy, M is the mass of the car in kg, G is the acceleration of gravity in meters per second squared (9.8m/s^2), and H is the height of the mountain in meters. Because of the conversion efficiency you'll likely only get about 70% of that as usable energy on flat ground at the bottom of the mountain. Likely even less due to wind resistance, rolling resistance, etc on the way down.

You certainly won't be able to drive the car back to the top of the mountain due to conversion losses which escape the vehicle as heat.
Audi did that in the etron as a bit of a gimmic and I think Bjorn Nyland (Tesla Bjorn) did a Youtube video about 2 weeks ago search for "Road trip to Doi Ang Khang in MG ZS EV" I think he gets quite a bit of energy back but it is only a short decent.
 
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