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Charging the batteries while in motion

Charging the batteries while in motion

I've been thinking about how Tesla could improve the range the cars on a singular charge for those who drive long distances but want to save on gas. What i would like to know is, normal gasoline cars use alternators to charge their batteries while they are driving, so why couldn't Tesla cars use a similar form of this? Where an electric generator is spun via the axles of the car moving. I am by no means an electrician or know how this could be an issue for the batteries, but my thought is. If you have four small electric generators near each wheel, while the car is moving a belt (like on an alternator for gas cars) would rotate it, producing electric charge. This in turn could be fed into a backup battery for the car or into the main one (depending on the model and issues with that) Like I said i am by no means an electrician but its just something I could see working to increase the range of a singular charge from Tesla's batteries.

jordanrichard | August 17, 2017

Ummmmm, ok.

First of all, your knowledge of hos a gasoline car works is some what incorrect. when a gas car starts, the battery supplies the power for the starter to literally crank the engine over. (aka start). Once the engine is running, the alternator doe in fact recharge the battery, but the primary purpose of the alternator is to provide a continuing source of electricity to run all the electrical components of the car. The car's battery is in the loop of this circuit. Meaning everything electronic is being fed from the battery, which is constantly being charged by the alternator. It's not as if the alternator charges the battery back up and then stops when the battery is full.

EVs, but more specifically Tesla do recharge via the wheels, but only when you are going down hill or when you left off the accelerator.

If you are purposing that there be generators at all 4 wheels to generate electricity all the time, that won't work. Well it would work except that you would be losing more than you gain. The more weight (generators at each wheel) and the more resistance (the wheels turning those generators) only increases your energy usage.

It is basic physics, you can never get the same or more energy than what it takes to create that energy.

Tropopause | August 17, 2017

Oh no. Here we go again.

Nexxus | August 17, 2017

@Tropopause, Took the words right out of my mouth! Surely this is Elon's way of playing with us, right? Getting people to log on and post these inane topics just to see the responses?

reed_lewis | August 17, 2017

@ ZacD - Basically it takes more power to move the car forward than you can get from generators/alternators attached to the wheels. When the car is moving forward, it still takes power to keep it moving, otherwise the car would stop. If you had generators on the wheels, the car would stop more quickly.

Remember, when you take you foot off the accelerator, you capture that forward motion and convert it back to electrical energy.

It would be called perpetual motion if you could do what you suggest. It is not possible.

Should_I | August 17, 2017

If the forward motion generated by the motor could also charge the battery enough to keep going that would be a perpetual motion machine which elementary school level science classes teach us won't work.

Rocky_H | August 17, 2017

The world keeps failing the New Year's Resolution I challenged them with.
https://forums.tesla.com/forum/forums/new-years-resolution-no-more-perpe...

Here's a thought experiment: You seem to think a generator spins freely with no effort or force needed to turn it, like you can just add alternators without slowing down the drive shaft. OK, instead of just one or two, add 50 of them, or 50,000,000 of them. None of them slow the car down or require extra energy out of the gas tank or battery to turn them, right? So that one car could supply all of the energy for your entire city without affecting its miles per gallon or efficiency in anyway, right? What a miracle! No, that's not how generators work. They convert energy, and never at 100% efficiency. About 90% is the best they get. So you take 100 units of energy from the battery, convert it with the motor to 90 units of kinetic energy in the motion of the car. Then, you TAKE AWAY that energy when you use the alternator to convert it back to 81 units of electricity to put back into the battery. You're just converting energy twice in a closed loop, turning 100 units to 81, with nothing gained. It's a perpetual energy wasting system.

This system is useful only when you do need to take away that kinetic energy by slowing the car down. But, this is not a new idea. It's called "regenerative braking", and every hybrid and electric vehicle already does this, because they already have a motor/generator right there on the drive shaft. It's a simple electronic switch to flip the input and output, and use that turning to generate electricity. But it DOES slow the car down, so you don't do this while you're trying to drive and keep your speed up.

OK, class dismissed.

Rocky_H | August 17, 2017

Argh. I said "anyway" instead of "any way". I feel ashamed, but I shall blame it on my brain being in electrical engineering mode instead of son of an English teacher mode.

Should_I | August 18, 2017

Hey, did the company that makes solar panels and electric cars ever think of putting solar panels on the roof, and would this give my MS60 unlimited range?

Ross1 | August 18, 2017

@jordanrichard:
I for one appreciated your kind response ..

DTsea | August 18, 2017

Should_i,

If by unlimited you mean 2-3 miles per day, sure!

Should_I | August 18, 2017

Sarcasm.

Uncle Paul | August 18, 2017

My idea is to put small diameter wheels on the front, and larger diameter on the rear.

That way the Tesla will be always going down hill.

It is a rule of Physics that a car going down hill will always get better mileage than one going uphill at the same speeds.

I noted that when going downhill, my X often indicates green on the gauge. Means it is adding electrons to the battery.

Simple idea, but wonder why Elon never thought of it (J/K of course)

Another idea would be to put a large fan on the rear of the car. This way it would always be running with a nice tailwind. Tailwind also helps range : >)

bish | August 18, 2017

@science_is_better,

Add ZacD to your list

vp09 | August 18, 2017

I love reading the answers to this post and all the ones like it.

Thank you especially Jordanrichard for your civil and careful explanation.

Everyone please remember than the photovoltaic effect was dismissed as impossible even when empirically observed. Finallly Siemens himself said it was real, but that he did not understand it.

The effect was dismissed as impossible, because everyone knew that for energy to be created, matter had to be destroyed. So to make electricity, you had to burn wood or coal or oil, not just place two dissimilar metals next to each other and tap the current.

Only with the advent of Quantum Mechanics was a theoretical model advanced that allowed for the observed data. Only then was the photovoltaic effect accepted as real.

I'm not equating perpetual motion machines with the PV effect, but, we might pause and consider not dismissing radical ideas out of hand simply because they don't fit with Newton's theories.

Uncle Paul | August 18, 2017

My idea is to put small diameter wheels on the front, and larger diameter on the rear.

That way the Tesla will be always going down hill.

It is a rule of Physics that a car going down hill will always get better mileage than one going uphill at the same speeds.

I noted that when going downhill, my X often indicates green on the gauge. Means it is adding electrons to the battery.

Simple idea, but wonder why Elon never thought of it (J/K of course)

Another idea would be to put a large fan on the rear of the car. This way it would always be running with a nice tailwind. Tailwind also helps range : >)

Remnant | August 19, 2017

@vp09 (August 18, 2017)

<< ... the photovoltaic [PV] effect was dismissed as impossible to make electricity, ... you had to burn wood or coal or oil, not just place two dissimilar metals next to each other and tap the current. >>

The OP proposed to capture (some of) the kinetic energy of the vehicle (KEV) and use it to recharge the battery, without realizing that any such capture BRAKES the vehicle and has already become a regular component of the REGENERATIVE BRAKING, in virtually all EVs and Hybrids.

OTOH, the PV effect converts radiant (solar) energy into the electric energy used to recharge the battery, if such an option is available in your vehicle. As the source of energy is the sun, rather than the KEV, it does not brake your vehicle.

The energy obtained from "[placing] two dissimilar metals next to each other and tap the current [that results if there is a difference of temperature between them (Seebeck or thermoelectric effect)]" is different from the PV effect and it is not clear why you brought it up.

https://en.wikipedia.org/wiki/Thermoelectric_effect#Seebeck_effect

Should_I | August 19, 2017

Photovoltaic is changing forms of energy not anything too exotic there.
Using the motor to turn a generator that powers the motor is the very definition of a perpetual motion machine.

And yes understanding of the world around us changes, you cite photovoltaic I cite the pollution caused global cooling that was pushed several decades more recently that solar was believed impossible.........what will tomorrow bring?

science-isbetter | August 20, 2017

@bish: ZacD might be a youngster just learning or dreaming. He doesn't get to join the list unless he argues.

eric.zucker | August 21, 2017

You guys just have it so complicated.

We just need a harpoon launcher (like the whale hunting boats) and pick your tow on the highway. Existing regen tops up your battery pretty fast at 50-60kW, then when full enough, reel in the harpoon, and drive away. You've been moving along while charging, so no wasted time at all. Autopilot keeps a safe distance following your towing vehicle, no problem.

Do you think the other guy won't notice his fuel efficiency go down the drain ? ;-)

reed_lewis | August 21, 2017

@Rocky_H - You are the son of an English Teacher also? Did your parent not only correct your language, but give you the rule that applied for that case? That is what my mother used to do.

As I always say: "My Mother was an English teacher - So I aint gonna use no bad English"

Rocky_H | August 22, 2017

@vp09, Quote: "Everyone please remember than the photovoltaic effect was dismissed as impossible even when empirically observed. Finallly Siemens himself said it was real, but that he did not understand it. "

Yeah, lots of people have incorrectly used the word "impossible". So? This isn't a new not understood phenomenon. This is something very well understood and provable with equations, and it's trying to make it do something it cannot do.

@reed, Yes, rules of course. The "anyway" thing was just a typo; not a grammar error.

Tropopause | August 23, 2017

There are some drivers that press both accelerator and brake pedals while cruising. Must be some kind of experiment for perpetual heating.

tylerw33 | March 25, 2019

What about having 2 batteries in a single vehicle that alternate... If one battery was being charged and the other used to power the vehicle? Then, once one is fully charged, the ECU what swap over the other battery to power the car? Theoretically, could you now use the motion of the wheel spinning to power and charge the car? Even better once solid state batteries come online, this would be super easy to have 2 of them on top of each other, one powering and one charging..?

jimglas | March 25, 2019

please, stop with the perpetual motion machines.

hammer @OR-US | March 25, 2019

Dont they teach conservation of energy in middle school science anymore?

Xerogas | March 26, 2019

@tylerw33: "What about having 2 batteries in a single vehicle that alternate
------
Why stop at 2? Teslas have thousands of batteries. Does that help with your idea?

reed_lewis | March 26, 2019

@tylerw33 - It takes more power to take electricity, convert it to mechanical energy and then back to electric energy than you get out of the system.

An alternator or generator requires mechanical power to produce electricity. It is not free! Therefore if you had an alternator or generator connected to the car's wheels, it would slow the car down which would then require more power to make the car go forward. So it would require more power to get some power to put into a battery.

Understand?

RJMIII | March 26, 2019

I've got an idea to fly a helicopter to the moon by enclosing it in a balloon filled with air. I leave on Thursday with ZacD and tylerw33.

kcheng | March 26, 2019

Tyler could get a Nobel Prize with an idea like that.

blue adept | March 26, 2019

Oh boy, here we go again...

Other than that,

@vp09

Way to encourage people to keep trying instead of discouraging them from trying at all.

+1

Good vibes all around!

blue adept | March 26, 2019

@eric.zucker

'Harpoons'!

Ha!

reed_lewis | March 27, 2019

Newton has three laws of motion, not theories. They have never been disproven.

blue adept | March 28, 2019

Umm, I don't think that anyone questioned "Newton"..."?"

reed_lewis | March 29, 2019

@blue adept - @vp09 said: "I'm not equating perpetual motion machines with the PV effect, but, we might pause and consider not dismissing radical ideas out of hand simply because they don't fit with Newton's theories."

They are not theories. They are laws. There is a difference. The laws are always true.

lilbean | March 29, 2019

These perpetual motion threads are in perpetual motion.

reed_lewis | March 29, 2019

...And as someone said... It is always solved in their mind by having two batteries. You use one to run the car and the 'magic' alternator to send power to the second battery. Then when the first battery is dead, you swap to the second and repeat the process charging the first.

Perpetual motion at its finest.

reed_lewis | March 29, 2019

I was recently at a electronics museum where they had a generator connected to light bulbs. You pedaled and created power. When more bulbs were attached it was harder to pedal.

Everyone who thinks up these crazy recharge schemes should have to pedal that bike.

blue adept | March 29, 2019

@reed_lewis

I was referring more so to vp09's '...we might pause and consider NOT DISMISSING RADICAL IDEAS OUT OF HAND simply because they don't fit with [conventional wisdom]...' comment than anything else as I feel that it is important to encourage people to expand their consciousness by experimenting with out-of-the-box thinking as a means of pushing our accumulated intellectual acuity just that much farther.

You know, THINK about it.

And, yes, Newton's Laws are, indeed laws, but there are ways around them if you THINK about it. ;-)

blue adept | March 29, 2019

@lilbean

All the same, it's good to see that people are making the effort to actually use their brains for something other than a space saver for the area between their ears.

Just saying....

lilbean | March 29, 2019

I agree. I’ve come up with a few clever ideas myself. :)

blue adept | March 30, 2019

Tesla related? Care to share?