# Shoot down my electric car charging solution. **URL:** \ **Category:** Factual Questions\ **Created:** [April 29, 2011, 1:09pm UTC](https://boards.straightdope.com/t/shoot-down-my-electric-car-charging-solution/580152 "2011-04-29T13:09:42Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![Philster](https://avatars.discourse-cdn.com/v4/letter/p/13edae/32.png) [@Philster](https://boards.straightdope.com/u/Philster)\ **Post date:** [April 29, 2011, 6:17pm UTC](https://boards.straightdope.com/t/shoot-down-my-electric-car-charging-solution/580152/21 "2011-04-29T18:17:04Z")
> [@spifflog](#): > > It’s still not a free lunch. You’re just getting to eat one that you’ve already paid for. You’re gonna propel cars forward and stop them whether you harness some residual energy or not, so it is free. Sort of like, “Hey, look at that billboard; I love free art” when driving on the highway. Yeah, smart-asses, I know you have to drive along the highway and burn gas to see it, but whether the billboard is there or not, I am driving along that highway to get to work, so it is free. ---
**Author:** ![Nars\_Glinley](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/nars_glinley/32/8177_2.png) [@Nars\_Glinley](https://boards.straightdope.com/u/Nars_Glinley)\ **Post date:** [April 29, 2011, 6:25pm UTC](https://boards.straightdope.com/t/shoot-down-my-electric-car-charging-solution/580152/22 "2011-04-29T18:25:52Z")
> [@Enilno](#): > > I think a similar topic has come up before. Anyways here’s what wikipedia says about [regenerative shock absorbers](http://en.wikipedia.org/wiki/Regenerative_shock_absorber). > > And from one of the [cited articles:](http://www.physorg.com/news188035494.html) Interesting. While I am encouraged that “my” idea isn’t totally without merit, I am saddened by the fact that I will have to continue to contribute to my 401K. ---
**Author:** ![Lukeinva](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lukeinva/32/17872_2.png) [@Lukeinva](https://boards.straightdope.com/u/Lukeinva)\ **Post date:** [April 29, 2011, 6:26pm UTC](https://boards.straightdope.com/t/shoot-down-my-electric-car-charging-solution/580152/23 "2011-04-29T18:26:46Z")
Why not just put that electrical coil doohickey on the wheels? The wheels have to turn for the car to roll so… just create electricity while the car is rolling. (Or maybe they already do this?) ---
**Author:** ![Nars\_Glinley](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/nars_glinley/32/8177_2.png) [@Nars\_Glinley](https://boards.straightdope.com/u/Nars_Glinley)\ **Post date:** [April 29, 2011, 6:38pm UTC](https://boards.straightdope.com/t/shoot-down-my-electric-car-charging-solution/580152/24 "2011-04-29T18:38:46Z")
> [@lukeinva](#): > > Why not just put that electrical coil doohickey on the wheels? The wheels have to turn for the car to roll so… just create electricity while the car is rolling. (Or maybe they already do this?) [Homer Simpson] Lisa, in this house we obey the laws of thermodynamics. [/HS] ---
**Author:** ![Musicat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/musicat/32/20189_2.png) [@Musicat](https://boards.straightdope.com/u/Musicat)\ **Post date:** [April 29, 2011, 7:12pm UTC](https://boards.straightdope.com/t/shoot-down-my-electric-car-charging-solution/580152/25 "2011-04-29T19:12:43Z")
> [@lukeinva](#): > > Why not just put that electrical coil doohickey on the wheels? The wheels have to turn for the car to roll so… just create electricity while the car is rolling. (Or maybe they already do this?) You are kidding, right? Where do you think the power to turn the wheels comes from (unless you’re going downhill)? ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [April 29, 2011, 7:27pm UTC](https://boards.straightdope.com/t/shoot-down-my-electric-car-charging-solution/580152/26 "2011-04-29T19:27:00Z")
> [@Musicat](#): > > You are kidding, right? Where do you think the power to turn the wheels comes from (unless you’re going downhill)? You put a windmill on the car to generate the electricity to turn the wheels. You could also put solar cells in front of your headlights to regenerate the electricity they use also. Also, you could use larger wheels on the back so the car is always going downhill. Or suspend a large magnet out in front of the car to pull you along by attraction. Geez, this stuff isn’t rocket surgery. ---
**Author:** ![gregorio](https://avatars.discourse-cdn.com/v4/letter/g/fbc32d/32.png) [@gregorio](https://boards.straightdope.com/u/gregorio)\ **Post date:** [April 29, 2011, 7:29pm UTC](https://boards.straightdope.com/t/shoot-down-my-electric-car-charging-solution/580152/27 "2011-04-29T19:29:35Z")
How about a piezoelectric generator? The amount of charge seems to be negligible in terms of propelling a car, but that energy could be diverted to auxiliary components or charge your electronic device and increase the car’s battery life. Shoe mounted piezoelectric generator: [Piezoelectric generator creates power from shoes](http://www.gizmag.com/piezoelectric-generator-shoes/14945/) ---
**Author:** ![Lukeinva](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lukeinva/32/17872_2.png) [@Lukeinva](https://boards.straightdope.com/u/Lukeinva)\ **Post date:** [April 29, 2011, 7:45pm UTC](https://boards.straightdope.com/t/shoot-down-my-electric-car-charging-solution/580152/28 "2011-04-29T19:45:04Z")
> [@Musicat](#): > > You are kidding, right? Where do you think the power to turn the wheels comes from (unless you’re going downhill)? Pardon my thinking if it is incorrect, but no matter how or what is making the wheels turn while they are turning couldn’t some gizmo be connected to the wheels? What’s wrong with this theory? In addition… a moving car creates wind so why not install a propeller that the moving car would cause to spin and thus create electricity? ---
**Author:** ![jz78817](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jz78817/32/1028_2.png) [@jz78817](https://boards.straightdope.com/u/jz78817)\ **Post date:** [April 29, 2011, 7:53pm UTC](https://boards.straightdope.com/t/shoot-down-my-electric-car-charging-solution/580152/29 "2011-04-29T19:53:43Z")
> [@](#): > > Pardon my thinking if it is incorrect, but no matter how or what is making the wheels turn while they are turning couldn’t some gizmo be connected to the wheels? What’s wrong with this theory? because nothing is 100% efficient. if you had generators in the wheels that were active all of the time, you will expend more energy pushing the car down the road than you can ever hope to get back from the generators. > [@](#): > > In addition… a moving car creates wind so why not install a propeller that the moving car would cause to spin and thus create electricity? because that will create additional aerodynamic drag, which means you’ll expend more energy pushing the car down the road than you’ll get back from the windmill/generator. Here’s a simple restatement of the laws of thermodynamics: 1. You can never do any better than breaking even 2. You can’t break even except at absolute zero 3. You can’t reach absolute zero. ---
**Author:** ![Lukeinva](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lukeinva/32/17872_2.png) [@Lukeinva](https://boards.straightdope.com/u/Lukeinva)\ **Post date:** [April 29, 2011, 8:12pm UTC](https://boards.straightdope.com/t/shoot-down-my-electric-car-charging-solution/580152/30 "2011-04-29T20:12:33Z")
> [@jz78817](#): > > because nothing is 100% efficient. if you had generators in the wheels that were active all of the time, you will expend more energy pushing the car down the road than you can ever hope to get back from the generators. > > because that will create additional aerodynamic drag, which means you’ll expend more energy pushing the car down the road than you’ll get back from the windmill/generator. > > Here’s a simple restatement of the laws of thermodynamics: > > 1. You can never do any better than breaking even > 2. You can’t break even except at absolute zero > 3. You can’t reach absolute zero. I just meant to charge batteries… ---
**Author:** ![jz78817](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jz78817/32/1028_2.png) [@jz78817](https://boards.straightdope.com/u/jz78817)\ **Post date:** [April 29, 2011, 8:15pm UTC](https://boards.straightdope.com/t/shoot-down-my-electric-car-charging-solution/580152/31 "2011-04-29T20:15:19Z")
> [@lukeinva](#): > > I just meant to charge batteries… then hybrids already do this, except the motor-generator is usually in the transaxle or final drive and not the wheels. ---
**Author:** ![Musicat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/musicat/32/20189_2.png) [@Musicat](https://boards.straightdope.com/u/Musicat)\ **Post date:** [April 29, 2011, 10:13pm UTC](https://boards.straightdope.com/t/shoot-down-my-electric-car-charging-solution/580152/32 "2011-04-29T22:13:15Z")
> [@lukeinva](#): > > Pardon my thinking if it is incorrect, but no matter how or what is making the wheels turn while they are turning couldn’t some gizmo be connected to the wheels? What’s wrong with this theory? > > In addition… a moving car creates wind so why not install a propeller that the moving car would cause to spin and thus create electricity? Your post is sooo close to a whoosh that I hesitate to respond, but just in case you are serious… :rolleyes: … The energy you are trying to extract from the turning wheels isn’t “free” unless you are always going downhill. You have to expend energy to get the wheels moving. Then, you are trying to recover some of that energy, but TANSTAAFL rears its ugly head and you can’t get out of it what you put into it because nothing is 100% efficient. So you burn a lot of gas, waste most of the energy, then recover a little. It’s a lot like the discount barker who says, “Sure, I lose a little on each sale, but I make it up in volume!” ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [April 29, 2011, 10:25pm UTC](https://boards.straightdope.com/t/shoot-down-my-electric-car-charging-solution/580152/33 "2011-04-29T22:25:22Z")
> [@Musicat](#): > > Your post is sooo close to a whoosh that I hesitate to respond, but just in case you are serious… :rolleyes: … > > The energy you are trying to extract from the turning wheels isn’t “free” unless you are always going downhill. You have to expend energy to get the wheels moving. Then, you are trying to recover some of that energy, but TANSTAAFL rears its ugly head and you can’t get out of it what you put into it because nothing is 100% efficient. So you burn a lot of gas, waste most of the energy, then recover a little. It’s a lot like the discount barker who says, “Sure, I lose a little on each sale, but I make it up in volume!” Basically, it’s the same reason [this](http://www.youtube.com/watch?v=YMSIzoKUbhM) doesn’t work (starting at 7:24). ---
**Author:** ![Lazlo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lazlo/32/9678_2.png) [@Lazlo](https://boards.straightdope.com/u/Lazlo)\ **Post date:** [April 29, 2011, 10:42pm UTC](https://boards.straightdope.com/t/shoot-down-my-electric-car-charging-solution/580152/34 "2011-04-29T22:42:14Z")
> [@lukeinva](#): > > Pardon my thinking if it is incorrect, but no matter how or what is making the wheels turn while they are turning couldn’t some gizmo be connected to the wheels? What’s wrong with this theory? > > In addition… a moving car creates wind so why not install a propeller that the moving car would cause to spin and thus create electricity? The problem is that generators create a load directly proportional to the amount of electricity they create. So while you can spin the alternator on your car freely, once you connect it to a battery and spin it up to operational speeds, it will take several horsepower just to keep it turning. If you’ve ever used an electric drill that has a brake, you’ve seen it in action. When you release the trigger, all it does is short out the motor and flux takes care of the rest. ETA: I’m sorry you have only gotten snark and half-baked answers about this, **lukeinva**. ---
**Author:** ![Lazlo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lazlo/32/9678_2.png) [@Lazlo](https://boards.straightdope.com/u/Lazlo)\ **Post date:** [April 29, 2011, 10:49pm UTC](https://boards.straightdope.com/t/shoot-down-my-electric-car-charging-solution/580152/35 "2011-04-29T22:49:41Z")
Here’s a video where you can see it. Notice when he hits the brake, the bulb lights and the wheel slows immediately. It even torques the stand a bit. [![](https://img.youtube.com/vi/NIQoOKJuRGY/hqdefault.jpg "Regenerative Braking Demo - Electric Bicycle") ](https://www.youtube.com/watch?v=NIQoOKJuRGY) Oops. And I just fully read **jz78817** ’s reply, which was non-snarky, so I apologize for the generalization. ---
**Author:** ![Nars\_Glinley](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/nars_glinley/32/8177_2.png) [@Nars\_Glinley](https://boards.straightdope.com/u/Nars_Glinley)\ **Post date:** [April 30, 2011, 3:44am UTC](https://boards.straightdope.com/t/shoot-down-my-electric-car-charging-solution/580152/36 "2011-04-30T03:44:00Z")
> [@jz78817](#): > > Here’s a simple restatement of the laws of thermodynamics: > > 1. You can never do any better than breaking even > 2. You can’t break even except at absolute zero > 3. You can’t reach absolute zero. My favorite summation is: 0) You must play the game. 1. You can’t win. 2. You can’t break even. 3. You can’t even quit the game. ---
**Author:** ![Musicat](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/musicat/32/20189_2.png) [@Musicat](https://boards.straightdope.com/u/Musicat)\ **Post date:** [April 30, 2011, 11:44am UTC](https://boards.straightdope.com/t/shoot-down-my-electric-car-charging-solution/580152/37 "2011-04-30T11:44:09Z")
Sing it, chile: [You can’t win, you can’t break even, and you can’t get out of the game](http://www.youtube.com/watch?v=6YrinCQOxB0) ---
**Author:** ![Lukeinva](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lukeinva/32/17872_2.png) [@Lukeinva](https://boards.straightdope.com/u/Lukeinva)\ **Post date:** [May 1, 2011, 12:27am UTC](https://boards.straightdope.com/t/shoot-down-my-electric-car-charging-solution/580152/38 "2011-05-01T00:27:37Z")
So let me get this straight. _I have to drive to work_… and while I’m driving… there is no way to somehow harness the energy created by my wheels? And no way to hook up a windmill to one of those wound-copper generator thingies and create electricity? Enough to recharge my rechargeable batteries? (or whatever) Why. ---
**Author:** ![gonzomax](https://avatars.discourse-cdn.com/v4/letter/g/e8c25b/32.png) [@gonzomax](https://boards.straightdope.com/u/gonzomax)\ **Post date:** [May 1, 2011, 3:34am UTC](https://boards.straightdope.com/t/shoot-down-my-electric-car-charging-solution/580152/39 "2011-05-01T03:34:38Z")
> [@Joey\_P](#): > > Also, something else this reminds me of that I would look into is wave energy. On the surface, it seem similar enough that it seems worth a casual look. When people attempt to capture wave energy, they’re trying to capture the energy produced by the vertical movement of the water, similar to what you’re trying to do with the car. > > Also, I remember something about someone trying to capture the energy of the ebb and flow of the water at shallow depths, again, something I’d look into. He had planted small, errr, things a few feet down in the ocean near the shore and as the water went back and forth he could capture the energy as the water pushed them around. Again, this seems similar to what you’re doing and I’d look into these things and see if they could be adapted (or not) and why they did or didn’t work. [http://peswiki.com/index.php/Directory:Vortex-Induced\_Vibrations\_for\_Aquatic\_Clean\_Energy\_(VIVACE)](http://peswiki.com/index.php/Directory:Vortex-Induced_Vibrations_for_Aquatic_Clean_Energy_(VIVACE)) Who says they don’t work/ They are building 2 wave plants in the Detroit river. ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [May 1, 2011, 3:57am UTC](https://boards.straightdope.com/t/shoot-down-my-electric-car-charging-solution/580152/40 "2011-05-01T03:57:30Z")
> [@lukeinva](#): > > So let me get this straight. > > _I have to drive to work_… and while I’m driving… there is no way to somehow harness the energy created by my wheels? And no way to hook up a windmill to one of those wound-copper generator thingies and create electricity? Enough to recharge my rechargeable batteries? (or whatever) > > Why. Because… there is **no** energy _created_ by your wheels. It’s all created by the engine - if you wanted to use the engine to charge your cellphone, well, that’s what the alternator and cigarette lighter is for. [Previous page](https://boards.straightdope.com/t/shoot-down-my-electric-car-charging-solution/580152.md?page=1) [Next page](https://boards.straightdope.com/t/shoot-down-my-electric-car-charging-solution/580152.md?page=3)