wind turbine on an ebike is stupid, right?

N

needWheels

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I saw an ebike on the news last week and the guy had a wind turbine of some kind on the front (along with a solar panel) apparently to charge or offset the load on the battery.

I was thinking, that's insane - a wind generator is only going to put load and reduce speed and be far less efficient at the power it creates vs the load it add - right?

But I figure I'll ask the experienced folks first. I can already tell from just a few ebike rides that wind and air resistance is our biggest enemy (and most annoying at full speed!)
 
A wind turbine on most bikes would be pretty stupid as it'd rob more power than it'd generate due to the differing efficiencies(It's ability to waste energy is 100% while it's ability to recoup that lost energy is less than 100%, so there'd be a net energy loss). But, it could act like a regen though the drag it'd provide throughout the ride would probably more than offset the energy gained during braking assuming the stops are relatively few.

However, if this turbine is readily retractable into a relatively aerodynamic position, through careful use(Like going down steep hills), it might produce net energy. But, there are probably cheaper and more effective regen implementations.
 
Yo

I havent seen the news story but of course it would make no sense unless he was using it to charge the bike whilst it was stationary? that would make sense, you would need a hell of a blade though to make any useful power.

Knoxie
 
The whole wind turbine on an ebike is stupid but central part of wind turbine - generator alone which is able to work as a ultra high torque low rpm motor - not at all.
http://endless-sphere.com/forums/viewtopic.php?f=7&t=4778

Best regards
 
Yup its stupid. I'd put the wind turbine where I'm going, or coming back to, and charge with it. Almost as stupid as my 65 pound generator in the back of my trike. It did work, kinda, but at a pretty steep penalty. 65 pounds of lifpo4 would go farther than I'll ride at a time. A little roll out solar panel will charge an ebike in less than a week.
 
Here is an idea along these lines (for mind entertainment, not practical purposes):
Start with the wheel set that has radial spoke pattern. Attach a plastic flap to each spoke that fills the entire area between each pair of neighbor spokes. Make it pivot along the leading spoke in both directions with a spring loaded mechanism that returns it to the wheel plane when no side force is applied. Now you have an automatic sail attached to each spoke. If you have any kind of side wind the sail flaps will work as wind turbine. If no wind is present they will return to the center position and present no aerodynamic load ;)
 
it would give you energy if the wind velocity relative to your moving bike is coming anywhere in between straight back to 90 degrees to the side.
 
Don't you see the analogy that wind turbine generator works at even lower rpm than direct drive hub ? So the hub could be made the same way as generator (for higher torque)
 
I just open my coat when the wind is at my back. How about this for a stupid idea, you could fly a kitesurfing sail while you ride.
 
Lessss said:
Has anyone actually measured the wind resistance loss versus electrical gain, or are ya'll spouting air from your rear orifice?
Click to expand...

heh

Nothing wrong with the physics. Energy can be extracted from the wind's motion relative to the ground independent of the motion of the motion of the bicycle. BUT any system losses will severely limit the speed the bike will be able to 'sail' at. (losses like drag, electrical resistance, hills, rolling friction, etc) With electrical coupling from turbine to wheels and a small turbine, I'd expect the max speed ground speed to be 10% of the wind speed directly into the wind and 110% of wind speed with the wind. Not much point there.

I've did a quick run of the numbers. If I equipped my Linear recumbent with a 5ft (1.6 meter) diameter turbine geared to the rear tire I could expect to sail at about 50% of wind speed directly into the wind. If I completely changed the gearing I could also expect to be able to go about 150% of wind speed with the wind. If I ever move to North Dakota or some desert I may build one.

My 2 watt hours,
Marty
 
lawsonuw said:
Lessss said:
Has anyone actually measured the wind resistance loss versus electrical gain, or are ya'll spouting air from your rear orifice?
Click to expand...

heh

Nothing wrong with the physics. Energy can be extracted from the wind's motion relative to the ground independent of the motion of the motion of the bicycle. BUT any system losses will severely limit the speed the bike will be able to 'sail' at. (losses like drag, electrical resistance, hills, rolling friction, etc) With electrical coupling from turbine to wheels and a small turbine, I'd expect the max speed ground speed to be 10% of the wind speed directly into the wind and 110% of wind speed with the wind. Not much point there.

I've did a quick run of the numbers. If I equipped my Linear recumbent with a 5ft (1.6 meter) diameter turbine geared to the rear tire I could expect to sail at about 50% of wind speed directly into the wind. If I completely changed the gearing I could also expect to be able to go about 150% of wind speed with the wind. If I ever move to North Dakota or some desert I may build one.

My 2 watt hours,
Marty
Click to expand...

Marty,

There is a flaw. When traveling with the wind, the apparent wind velocity seen by the turbine will go to zero as your velocity relative to the ground increases, so anything approaching wind speed simply isn't going to happen. Significant cross winds would create the most benefit, but would also be the most impractical for any 2 wheeled vehicle. The only practical wind turbine for an electric bike would be a folding unit that you pop out to charge your batteries while parked.

John
 
John in CR said:
When traveling with the wind, the apparent wind velocity seen by the turbine will go to zero as your velocity relative to the ground increases, so anything approaching wind speed simply isn't going to happen.
Click to expand...

That's not a problem when going with the wind. The 'trick' is that when you sail with the wind power comes from the ground and runs the wind turbine as a fan. And once again losses in the system limit how fast a person can go relative to the wind. http://www.youtube.com/watch?v=aJpdWHFqHm0 shows this pretty clearly.

For cross winds, a conventional sail is a more efficient and simpler system. The main issue here is balancing a bike in spite of sail forces knocking you around, and having to tack to sail into the wind.

Marty
 
That was an interesting video, but not video of the thing described in the original post. I couldn't figure out if he was sailing down wind, powering a motor, or running a propellor from a battery. Wind is a signifigant force that can be harnessed for sure. I love sailing, especially windsurfing. I still say charge your lifpo4 with the wind turbine.
 
I wish I could remember it in more detail (and what show I saw it on but it was a morning news segment).

It was mounted in the FRONT of the bike BTW, which only made me wonder more "WTF"

Even the small solar panel seemed silly too - at the tiny rate that would put out, it would be a trickle charge and do nothing for a series of deep discharging SLA's, no?
 
needWheels said:
I wish I could remember it in more detail (and what show I saw it on but it was a morning news segment).

It was mounted in the FRONT of the bike BTW, which only made me wonder more "WTF"

Even the small solar panel seemed silly too - at the tiny rate that would put out, it would be a trickle charge and do nothing for a series of deep discharging SLA's, no?
Click to expand...
Sounds like Wiley Coyote sailboarding with an electric fan.

News operations will put anything on the air... if they can get pictures, it must be news. :roll:

They actually came through my neighborhood last night looking for "a guy with an electric car..." Fortunately, my buddy called and gave me a headzup... he told em I was outta town. :mrgreen:
 
*BUMP*
...maybe related...

Over in the EU:
http://www.windenergyevents.com/


Windenergy Events are having a little race today...

Guess their experience has been with larger vehicles so far like this:
View attachment 5


But today they're hosting six teams for a different race with smaller vehicles...

Some of the competitors:
http://www.inventus.uni-stuttgart.de/aktuell.html
InVentus.jpg

Not sure what these guys will bring to the race:
http://www.windturbineracer.com/
In their (flash) pics section there is a model of a four-wheeler with air prop, looks like...


The Zefyros Racing Team have something like this:
http://saam.mech.upatras.gr/zefyros/
zefyros.jpg


And there's Baltic Thunder:
http://www.baltic-thunder.de/index_e.php
The videos on their site are amusing... no pics but a drawing that looks like this:
Baltic.jpg

From the Baltic Thunder site:
A Darrieus rotor has been chosen for the "energy-extracting" device.
The energy required for the drive is taken from the wind by means of the rotor and transferred to a generator by the rotor. The generator feeds in the electrical power with the help of corresponding power electronics into the so-called DC-link circuit. The motor side converter is being powered from the DC-link and drives the propulsing motor drive. The flow of energy is controlled by a microcontroller.



My fav, based on a 15th-century Italian design... the headwind bicycle... errr trike... errr quad... anyway, seen on the Windenergy Events site an earlier prototype:
turbobike.GIF

And what I guess they brought to race day:
turbo.jpg


Guess most of these guys are just using mechanical transmissions...

Some of the race rules:
Guidelines
The organizer has put different framework conditions by which the most important ones shall be mentioned here.:

Land transportation vehicle with wheels, controlled of a driver
Propulsed by a device with spinning blades or turbine coupled to the wheels
Temporary storage of energy is allowed during the ride (the storage device has to be empty at the start); the device will source and store it's power from a combination of wind and battery power solely during the course of the race
Outside dimensions: length max. 4m, width: max. 2m
Maximum rotor area 4m2
Different system security features



One other e-vehicle I've mentioned here before but still a fav EV for me, Bill Bruders Wind Wagon:
http://www.evalbum.com/309
imgm.php


tks
Lock
 
Fun looking stuff. but actually that is just landsailing. It can be fun with a big skateboard and a windsurf sail. Just don't crash, ever.
 
Hehe... Ya man. I have land-sailed on three wheels w/sail. Hitting maybe 2x wind speeds, flying one wheel, spinnouts in the gravel... Also hit about 2x windspeed on a trimaran with foils... Iceboats (the big ones) hit about 5x wind speed, so not hard to hit 100mph really fast in right conditions.

What's interesting with the props is the possibility to regen (or is it just gen?)when stopped at least. Most of those designs (above) seem to be designed to go more or less directly into the wind. The Inventus maybe on all tacks (directions) but the Darrius doesn't care. It'll work w/any wind direction w/out adjustment while the horizontal axis machines need to be trimmed into the apparent wind.

Underpasses, low wires and branches... even the odd pigeon... might make things a bit... awkward :twisted:


Tks
Lock
 
The best way to do it is to buy a used hoverboard and remove a wheel then mount it friction drive to the rear wheel with an arm so you could engage it/disengage while riding. Add a 3 phase bridge rectifier 50A and a charger for the 2nd battery, though drag will be created but with leg power it may pay off.
 
I am a curbside scavenger, so I removed a 3 phase motor from a washing machine and set it on a bucket so I could spin it by hand. A3 phase bridge rectifier attached to the phase wires and a decent sized bumper mount LED. I can really feel the cog when turning it compared to a single 110v bulb. The resistance is like an exercise machine!
 
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