Electric Car Battery Recharging While Moving! Extend the Battery Range.

i read that in some electric cars the main battery is given a very small boost... when the brakes are applied to the wheels by BRIEFLY converting the main motor into a dynamo.

this is to recover a very small amount of energy to recharge the battery.


it occurred to me if the electric motor is powering the front axle why not have a dynamo in-line to the back axle?

as the car moves forward it will turn the back axle automatically helping to charge the battery.

this will extend the range of the battery.

some people have tried adding windmills/fans/turbines to the roof of the car to get head wind to help charge it but the simplest and lightest way ,no drag method is to have an in-line dynamo with the back axle.


this is NOT about over unity devices or perpetual motion as losses occur in converting electric power to motion in first axle and then motion back to electricity in back axle.

this is about extending the range of the battery by charging it from the surplus rotational motion of the back axle as it spins from the rear wheels which are pulled by the front wheels powered by the battery.

any comments?

reply to post by nobodysavedme


It's not a good idea because adding a charge to a battery before it's fully discharged reduces the battery shelf life considerably. That's why hybrids that use the recharge when braking method are so hard on batteries.

reply to post by nobodysavedme


Good question.
I don't think most of us can afford an electric car though.

Originally posted by nobodysavedme
i read that in some electric cars the main battery is given a very small boost... when the brakes are applied to the wheels by BRIEFLY converting the main motor into a dynamo.

this is to recover a very small amount of energy to recharge the battery.


it occurred to me if the electric motor is powering the front axle why not have a dynamo in-line to the back axle?

as the car moves forward it will turn the back axle automatically helping to charge the battery.

this will extend the range of the battery.

some people have tried adding windmills/fans/turbines to the roof of the car to get head wind to help charge it but the simplest and lightest way ,no drag method is to have an in-line dynamo with the back axle.


this is NOT about over unity devices or perpetual motion as losses occur in converting electric power to motion in first axle and then motion back to electricity in back axle.

this is about extending the range of the battery by charging it from the surplus rotational motion of the back axle as it spins from the rear wheels which are pulled by the front wheels powered by the battery.

any comments?

edit on 19-8-2011 by nobodysavedme because: clarity.

I am sorry, but that is just about impossible to do. Regenerative braking works for exactly the reason that your proposal will not. It takes energy to turn a motor when the windings are energized. Don't believe me? Full field your cars alternator with the belt off. Then try to turn the pulley. Good luck with that and I hope you don't get a hernia trying. Sorry my friend, but there is no "free lunch" no matter how much "the messiah" might try to make you believe in it.

Sorry, wont work, you would use just as much as you put in.
Pushing current through a stator coil takes some oomph.

As other people have mentioned, the laws of thermodynamics apply which makes this idea null and void. Regenerative breaking works because it is has kinetic energy that would otherwise not be utilized.

Originally posted by sonofliberty1776

Originally posted by nobodysavedme
i read that in some electric cars the main battery is given a very small boost... when the brakes are applied to the wheels by BRIEFLY converting the main motor into a dynamo.

this is to recover a very small amount of energy to recharge the battery.


it occurred to me if the electric motor is powering the front axle why not have a dynamo in-line to the back axle?

as the car moves forward it will turn the back axle automatically helping to charge the battery.

this will extend the range of the battery.

some people have tried adding windmills/fans/turbines to the roof of the car to get head wind to help charge it but the simplest and lightest way ,no drag method is to have an in-line dynamo with the back axle.


this is NOT about over unity devices or perpetual motion as losses occur in converting electric power to motion in first axle and then motion back to electricity in back axle.

this is about extending the range of the battery by charging it from the surplus rotational motion of the back axle as it spins from the rear wheels which are pulled by the front wheels powered by the battery.

any comments?

edit on 19-8-2011 by nobodysavedme because: clarity.

I am sorry, but that is just about impossible to do. Regenerative braking works for exactly the reason that your proposal will not. It takes energy to turn a motor when the windings are energized. Don't believe me? Full field your cars alternator with the belt off. Then try to turn the pulley. Good luck with that and I hope you don't get a hernia trying. Sorry my friend, but there is no "free lunch" no matter how much "the messiah"

might try to make you believe in it.

I was talking about a dynamo.

not field windings.your alternator example is flawed as it is connected to a cold engine which needs to be started.so it is very heavy and you need a lever to turn it.

i am talking about a highly lubricated axle which is ALREADY TURNING due to the motion of the car with a in-line dynamo.

i have often seen cyclists with a dynamo attached to the back wheel and as they peddle it supplies energy to the lights.

this is the same principle

reply to post by nobodysavedme

i have often seen cyclists with a dynamo attached to the back wheel and as they peddle it supplies energy to the lights.

The lights are being peddled by the power of the person peddling the bike. Taking away energy that is creating momentum for the bike (albeit a small amount). If you did this on a car, you would be wasting energy, constantly taking away from the energy reserve and limiting output through inefficiency.

Awwwwww i remember the days less thermaldynamic knowlege. Ohhhh the things i came up with. But then, damn it the math. The damn math doesnt lie. And from there i learned the truth. So i say put your ideas to the test. Apply math to the conception. Enjoy the trip! I have come to learn everything is relative. Compare atom binding to the universe's planetary interactions. Anyway. Enjoy your trip my good friend.

God speed,

Here is an experiment to prove it to yourself.
Take a small electric motor from a toy or what ever. No gears or mechs just the motor.

Spin the motor with no connection to the power terminals. It will spin freely.
Now connect a wire from one terminal to the other (create a short), then spin the motor. It will not spin freely.
The load from the wire is the same as charging a battery.

If the front wheels are trying to pull the car forward, the back wheels will be trying to slow the car down. Therefore the front motor willl have to work harder (pull more current) to go the same speed.

reply to post by samkent


But but what if you distribute the power equally to the front and back at the same time? AWD yayayay

The same reason that you can not use a small motor to spin a generator, to power a bigger motor to power a bigger generator...ect

Friction, decay, and resistance steal energy from any system.

Momentum, energy, and angular momentum can not be created or destroyed. System input is always greater than system output due to the laws of themodynamics.

In an ideal situation, one which could not happen in real life, there would be zero difference in battery life.

In the real world, your idea would decrease battery life.

All of the energy that the generator on the back axle generates is coming from the car's motor. In simple terms, if the generator on the back axle is putting out 1amp, then the car's drive motor will draw MORE than 1amp, in addition to the regular load from moving the vehicle. It's never going to work.

As someone else mentioned, the reason regenerative breaking works is because a moving car has a lot of momentum. If you apply the breaks and stop the car normally, all that energy is lost. Regenerative breaking allows you to capture a portion of that lost energy.

Cool idea that is basically a variation of the idea I'm sure thousands of people have had, and then quickly realized is impossible. Even with a zero friction, and zero resistance setup, you are still only going to be at 1:1, which doesn't accomplish anything.

No, it will not recharge the battery as anyone who has every done first grade university physics knows, because they have probably tried this (I did). Adding a generator creates extra resistance that the engine will have to work against, meaning the engine will have to work harder. Neither electric motors or generators are 100% efficient so the actual total efficiency of the vehicle would go down meaning an actual reduction in range.

reply to post by nobodysavedme


There is a concept of generating small amounts of current using motion and electric fields and transistors called the "Hall Effect".

If you recall those sneakers years ago with the LED's in them, this is how they were being illuminated when the kids jumped upon the heel.

Conceptually you could use this principle on rotating bodies of the axle shafts to generate small amounts of current as a trickle charger does in order to charge the batteries.

Here's and explanation of the Hall Effect.

en.wikipedia.org...