Regenerative Running?. (Ability to turn-on regenerative breaking even when not breaking.)

Regenerative Running?. (Ability to turn-on regenerative breaking even when not breaking.)

What if tesla has this option to always regenerate electricity at all times even without breaking?

GoTeslaChicago | 23 March, 2013

very poor mileage

Tesluthian | 23 March, 2013


I do think it's possible to get some mechanical/electrical energy from the suspension and shocks on the MS. 4500 lbs of vehicle flexing various metal parts of the car is a lot of force that can be captured and returned to the battery. The bumpier the ride, the more mechanical electricity returned to the battery ! Someone will have to design and invent it first.

I also think there is some mechanical/kinetic energy recovery possibilities for the tires, to return electricity to the battery. For example, at the point where the four tires contact the road, 4500 lbs of force is pushing on the tires from the road on the model S. When the tire roles, the force rotates around the tire and could be captured. The tires of course would have to be re-invented. And I don't know if centrifugal force would cancel out the effect.

These two ideas would be in addition to regenerative braking , which only works when the brakes are applied. However, one way to possibly generate (not regenerate) electricity from the wheels, that would be simpler and faster to invent is thus:
Make the rim of the wheel out of a hardened magnet. Put an electric wire through 2 axles connecting the four
wheels and leading back to the battery. When the magnetic rims of the tires rotate around the metal wire, it
will produce free electricity since the rim and tires have to rotate anyway when the car is in motion.

For quick verification and background info on this see the section "Other Configurations" in the link below.

GeekEV | 23 March, 2013

I don't think making the wheels into generators will help. They call it regenerative BRAKING for a reason. Yes, it generates power but also drag.

abhibeckert | 23 March, 2013

Anything that takes a moving car and generates electricity from it will slow the car down. So you can only recover power while braking (or travelling downhill).

There is a company making suspension that generates electricity... I can't remember the name but it exists and supposedly works better than conventional suspension (more comfortable ride, longer lasting parts, etc) but as far as I know they mostly focus on trains and military trucks. You need either a vehicle that is really heavy (train) or that is travelling at speed over rough terrain (military truck).

stevenmaifert | 24 March, 2013

Well, I wasn't a physics major, but I always thought that to extract energy of motion, you have to expend energy to create the motion. If that energy source is internal to the machine, like the car's battery, you will never recover 100% due to external factors like aerodynamic drag and tire friction with the roadway and I2R losses in the electric motor. I wasn't a physics major :)

Alex K | 24 March, 2013

@Tesluthian | MARCH 23, 2013: one way to possibly generate (not regenerate) electricity from the wheels, that would be simpler and faster to invent

You should have stopped at your first two ideas, which could theoretically return some energy. There are many piezoelectric energy recovery devices in the works. Also, I've seen some references for magnetic suspensions that could return some energy. Magnetic rims, however, would not give you any more recovered energy as previous people have mentioned.

olanmills | 24 March, 2013

"What if tesla has this option to always regenerate electricity at all times even without breaking?"

Well there could be one of two situations:

A) The car wouldn't be able to move.

B) We would have all be transported to Hogwart's School of Witchcraft and Wizardy

As Tesluthian mentions, it may be possible to capture other unwanted motion from the car (NOT the forward motion), such as the up & down travel of the body on the suspension, but that would require entirely different hardware in addition to the regenerative braking system. Depending on how efficient and costly such a system is, it may or may not be practical for a passenger car.

However, do not listen to the rest of what Tesluthian is saying. Free energy is not possible. His "magnetic rims" idea is basically just another form of regenerative brakes. If they are connected to the battery, they will slow the car down.

My neighbor asked me a similar question the other day. He even claimed to have once been a mechanical engineer. He was aksing about the car, and when I explained that it's simple to use and that I just plug it in when I get home, he was surprised. He thought it ran on unicorn farts and rainbows. He seriously thought that the car magically charged itself while I drove it.

It really bothers me that people don't understand basic physics.

TeslaRocks | 24 March, 2013

April 1rst is not until next week, if this is a joke. The fascination with perpetual motion machines seems to be, well, perpetual.

alcassfast | 24 March, 2013


"...unicorn farts and rainbows."

I chuckled.

Tesluthian | 25 March, 2013


"... understand basic physics".

I plead guilty, barely passed high school physics, Took non-math conceptual physics in college. Upon further reading & viding, I see inducing current by rotating magnets inside a metsl wire coil also increases resistance and makes whatever is turning the magnets harder to turn.

That said said, I will attempt to salvage the rim idea to just barely recover enough energy that's say is wasted. Just enough energy to have say have lighted rims at night.

First start with spinner rims, see link. These are those rims that keep spinning after the car stops.

Have a closed loop of wire around the outer rim. The inner spinning rim is your turning magnet inducing the current. Also have storage storage batteries inside the rim. This idea will use centrifugal force and inertia ( A body in motion tends to stay in motion).

DURING THE DAY, when car accelerates, the system is off untill a certain spinning speed is reach by the inner magnetic, rim spinner. Then the system turns on, the rim magnet spinning induces current in the outer rim coil, that is saved in the battery inside the rim. This also creates electrical resistance, and slows the spinning rim down. When the spinning rim slows down too much to generate electricity, the system shuts off, and this allows the rim spinner to accelerate again. This repeats during the day, charging up the internal rim batteries that will power the rim light bulbs at night.

AT NIGHT, the senors turn the system on, and you have lighted rims until the batteries wear out. If that happens the lights only turn on when current is generated as described during the day.

I din't mean this as a desirable device right now, just a proof of concept: The spinning tires & rims can generate electricity from unused, not free, energy of the wheel's turning motion thru inertia, and centrifugal force, which some day may make a future rap star very happy. The whole unit is self contained and closed loop, nothing connects to the car's battery.

If you don't like the battery in the rim, the system still works without it, only part of the time at night when the system switches on to slow the spinning rim when inducing current. Even when stopped, the rim lights stay on a short while until the rim spinners stop spinning.

Tesluthian | 25 March, 2013


April 1st...

Not my thread , just going with the thread program. Although tempting to think that. +1

Tesluthian | 25 March, 2013

Looks like there is unanimous agreement that the suspension could definitely add some electric juice. Now I see it has been discussed on other threads and there are links to people working on that very thing. See below:


I think this type of thing would add some engineering panache to the Tesla lineup of cars.

Tesluthian | 25 March, 2013

Alex K

...stop at your first two ideas...

I agree capturing even a small amount of forward energy without any drag is a tough one. And the only practical promise right now is on capturing suspension motion.

That said , an impractical way to capture the tire contact with the road requires re-inventing the wheels. See link which has already been posted elsewhere herein.

If the tire could be divided into flexible sections flexing up an down as it makes contact with the ground, (as in the video), then, just like the suspension, those forces are electrically recoverable. Granted its doubtful anyone will have one any time soon. I'm just saying its possible. I'm not even saying its practical, economical, etc.

However, one thing everyone agrees on, you can't turn on regenerative braking all the time to create more energy, only when you want to slow down, I agree.

olanmills | 25 March, 2013

Tesluthian, "capturing even a small amount of forward energy without any drag" is not a "tough one"; it's impossible. It would be like saying removing water from a cup whilst the volume of water remaining in the cup remains the same is just a tough problem, but could be solved.

Your idea to have lighted the rims would, in effect, just be drawing extra electricity from teh car's main battery.

The key thing when trying to make something more efficient is to think about where we currently waste energy and either try to avoid wasting it, or try to recapture it.

So think about braking. When you use the brakes on a car, on a bicycle, on a train, on an airplane, etc you're always wasting energy. Imagine if in a car, you started moving, and then you put the car into neutral and then you turned of the engine. No gas is being used, right? So no further energy energy is being fed to the engine. However, if you don't touch the pedals, the car will keep moving forward for some period of time, right? That's because when you fed gas into it earlier, you converted the energy in the gas into kinetic energy. So what happens when you use the brakes? Well regular brakes use friction to slow down the car. They turn the car's kinetic energy (which came from the gas) into heat. This slows the car down. Braking is "wasting" energy because if you were not to use the brakes, the car could have kept moving forward for some time.

That wasted energy is something we can try to recapture. That's what regenerative brakes do. We're already moving forward, and now we need to stop. Instead of turning the forward motion energy into heat (like regular brakes), we can try to turn some of it into electricity which can go back into the battery. When you want to brake, it means you have undesired motion (going forward), and you want to stop.

That's the key thing. Undesired motion can be turned into useful energy instead of waste. For example, when you go over bumps, the car's body would naturally move up and down, but we don't like that. So we use suspension systems which reduce this unpleasant motion by a combination of relative motion in the suspension system (but not the body), and friction in the suspension system. Both of these things are energy that is basically wasted. We could try to instead turn the potential motion of the suspension system into energy.

However, desired motion can't be turned into other energy without reducing the desired motion. That's why you can't use the forward energy of the car to, for example, power lighted rims. We actually want to move forward. You're right in assuming that the rotating wheels have energy, but that energy is what is making you move forward. You could trade some of that energy to light up the rims or whatever, but then the car will either slow down, or you'll have to draw an equivalent amount of energy that the lights use from the battery to keep moving forward at the same speed.

Energy "generation" is sort of a misnomer. You can't generate or create energy. You can only take energy from one thing or one form, and transfer it to another. For example, hydropower is not free. When you put a hydropower station on a river, the flow of the river actually slows down. When you put up windmills to capture energy from the wind, the wind slows down (albeit only a tiny bit). If you draw any energy from the motion of a car, the car must either slow down, or you must feed more energy into the car to keep it going.

Rhinotyme | 6 April, 2013

"What if tesla has this option to always regenerate electricity at all times even without breaking?"

Is regenerative braking causing MS to break?

RanjitC | 6 April, 2013

@olanmills @tesluthian suckered you. It's surprising people like joelbryan exist. Says something about the power of the public school teachers unions. Maybe we should use that power to generate free electricity.

Brian H | 6 April, 2013

The liberal mind believes deep down that there is always such a thing as a free lunch. You just need to smile sweetly enough.

svennsl | 7 April, 2013

Thinfilm solar-cells in the roof.
No extra weight.
A small step,but?

Roadster | 7 April, 2013

Like the Fisker Karma? With todays solar cells, that´s pretty expensive and pretty ineffective. Perhaps i a couple of years though.