Welcome to Tesla Motors Club
Discuss Tesla's Model S, Model 3, Model X, Model Y, Cybertruck, Roadster and More.
Register

Charging car battery on the move with wind power

This site may earn commission on affiliate links.

Retellect

New Member
Nov 26, 2009
2
0
UK
My son came to me today with one of the strangest and creative concepts on how to help charge an electric car with wind power to make it more efficient. He suggested that one could cut out "scoops" in the cars body that would aerodynamically channel air down a tunnel. Using a method similar to what dyson used in their bladeless fan called the Air Multiplier, you could amplify that airflow to spin an internal motor generator.

The way he explained it to me, it would only be passive. That means the aerodynamics would assist cars efficiency and drive a highly efficient motor generator without causing drag. What are your opinions on this idea? Do you think its worth looking into?
 
As Tdave says, there is no free energy.

One place where you can conceivably get some useful energy is to use this as an air brake (like the spoiler on the SLR). But it seems like a very complicated system for not much gain.
 
There was a such thing as sail cars. I don't know if this would be more effective or not, but i'm guessing it might work in a stiff enough wind. No wind, no dice.

Here's a thought experiment:
A 30 mph (50kph) headwind should produce enough energy to allow someone to travel 2-3 mph. and traveling 33 mph should be a marginal increase in drag.
 
ther is only one way we can use wind energy and that is if we are able to catch side or tail wind, but that is going to be to little to utilice
Mark, surprisingly there is a complicated way to use any wind over the ground--tailwind, headwind, whatever. There is no way to gain anything if the wind isn't blowing over the ground, though.

See this blog as to how a car with no motor whatsoever and no stored energy did it with both a tailwind and a headwind. It's fascinating and counter intuitive.

A Long, Strange Trip Downwind Faster Than the Wind

and

 
Mark, surprisingly there is a complicated way to use any wind over the ground--tailwind, headwind, whatever. There is no way to gain anything if the wind isn't blowing over the ground, though.

See this blog as to how a car with no motor whatsoever and no stored energy did it with both a tailwind and a headwind. It's fascinating and counter intuitive.

A Long, Strange Trip Downwind Faster Than the Wind

and

It's on an airport, but I'll bet it'll never take off!
 
Not sure what reinvigorated this thread. At any rate, these techniques are well-proven in literature by Dr. W.E. Coyote and the Acme Corporation, et. al.
1673448645380.png

1673448665682.png
 
  • Funny
Reactions: HankLloydRight
Not sure what reinvigorated this thread. At any rate, these techniques are well-proven in literature by Dr. W.E. Coyote and the Acme Corporation, et. al.
View attachment 894486
View attachment 894487
Yep. The top coyote situation actually works (poorly) in a surprising way:


The Myth busters show that it can work. (It works because of the net force of the change in motion of the air). It generally works better with just the fan pointing backwards like an airboat or airplane.

The bottom one won't work because it is a closed system (the water remains in the tub being carried whereas the air in the first picture is not constrained this way!).

The DDWFTTW (Direct Down Wind Faster than the Wind) cart in the earlier posts most assuredly work and as the inventor and others have stated "It in no way violates any laws of physics." It just uses energy gained from slowing the wind over ground to power it (so no, it isn't a perpetual motion machine either and it won't work at all if the wind isn't blowing over ground no matter how fast it is pushed or starts out. In other words, no wind over ground, no go. However it does work in zero relative wind (to the cart itself!) which is what surprises so many people.

So interestingly we have the following outcomes which all adhere to conventional physics laws:

DDWFTTW cart--works very well as long as the wind blows over ground and the cart is well engineered (proper gearing and low friction and large propeller). Doesn't work with no true wind but works with zero relative wind. (not a joke or fake).
Coyote with fan--works minimally if engineered with really low friction (like the mythbusters with their boat)
Coyote with boat motor in tub pulled along--doesn't work at all as long as water stays in tub.
 
In a nutshell, with the OP's question. As long as there is an external energy source (sun, wind, fuel, rubber bands, etc), a well engineered vehicle can generally take advantage of it for propulsion in most situations. There are no vehicles which create energy or can power themselves from their own momentum, motion, etc, without an external source of energy. That would be perpetual motion and it never ever works in an environment with any frictional losses. (Satellites, planets, moons, the galaxy, etc. keep going around because space is very low friction).

So Solar power cars work (Aptera is an example you can actually purchase).
Wind power vehicles work (sailboats and land yacht racers can actually be purchased also).
Fuel powered vehicles work from stored chemical energy in their fuels and we have plenty of examples of this!
No perpetual motion vehicles work. (vehicles without a source of external energy)
 
The good news is that I haven't see this kind of idea surface for many years. Back in the early 2000's, a perpetual motion ride would be floated on nearly every EV forum about once per week or so.
The world is getting educated!
Agreed. Or the public is finding out that the Perpetual Motion schemes never work. The somewhat sad part is that most people can't tell the difference between perpetual motion and "available energy conversion" machines.

Bottom line: Net positive energy machines (classically defined as "Perpetual Motion") do not work. Machines do not create energy, they only transform available energy to potentially useful energy and waste heat.

Perpetual motion is a bit of a misnomer since things like planets, stars, galaxies seem to "perpetually move" over time. But in general they are just moving without friction like a spaceship which is required by conventional physics (Newton's first law of motion). Stars are powered by nuclear fusion of their constituent elements. The only fundamental question is where did the energy come from to begin with (some physicists posit that the overall universe, when gravity is taken into account is net-zero energy).

Other people get confused over machines like the "Direct Down Wind Faster than the Wind" Car and declare it as "impossible" because they think it is perpetual motion or "can't outrun it's energy source". Both are wrong and this machine works because it simply converts the energy obtained from the wind over ground being slowed in its normal operation. This is a totally valid energy source as it is the same source that a sailboat uses to operate. Just like a sailboat, the cart never outruns the source simply because it is going faster than the wind powering it since it is immersed in continuously replenished moving air (over ground) which it slows over the ground as it operates (thus diminishing the wind energy with respect to the ground and utilizing the energy obtained to power the vehicle). But counterintuitively, it can work in zero relative wind as long as the wind over ground is blowing at an adequate speed. Finally, "available energy" is a necessary condition (no wind over ground--no go), but it isn't sufficient. The vehicle has to be capable of transforming adequate amounts of available energy to a useful form for propulsion and more than overcoming all internal losses (frictional, aerodynamic, heating, etc.) with enough left over to operate (this is the part where careful engineering comes in).


Since many people do not have much of physics education, this all gets confusing and most just don't know who is correct or how to evaluate any of the claims.
 
Last edited: