A Double Whammy - The Wind Powered Bike Light
by Warren McLaren, Sydney on 07.21.06
Skateboards and mobile phones have gone wind-powered. so why not bicycles? Two of our faves in one. Bonus. Taiwan designer Hsieh Jung-Ya and his firm, Duck Image, won kudos from European design comps, like Red Dot, for his concept of a wind-powered bike light. A mini turbine is mounted on the handlebars and uses the bikes momentum to drive the blades. These in turn power a 1700 lux LED light. (A bike moving at 21kph is said to produce continuous power of 3.5 volts at 70mA, with the little generator whizzing round at 850 revs per minute). Unlike the problem with many hubs that stop working when the rider stops, this gizmo comes with a rechargeable lithium battery for constant light. Combined with gyroscopically powered LED pedals (with or without battery) this could be a groovy combination. Until that is we receive complaints from the Moth Protection Society about furry winged critters flying into the turbines path. ::Duck Image (Flash Alert!!! You have been warned), via Red Dot.
Ok, another example of sketchy science. Unless you are planning on riding on a very windy day, these things aren't powered by wind, they are powered by drag. Whatever power you gain for your light from the blades comes at the expense of energy you put into pushing your
bike through the air.
Since the energy is coming out of your pedaling anyway, you may as well use a more efficient coupling by using an old tire spinner generator. Or find some way to couple to your pedal crank so the light doesn't dim with gear changes or ride with a tail wind.
It'd be interesting to see if this is much better than just a direct drive model (off your hub). How fast do the bearings wear out (most wind generators have 1 year warantees...it'd be interesting if this little guy has a lot more life...and not fill up a land-fill with quick-dying plastic techno doo-dads)?
Bonus points if the rechargeable lithium battery is user-replaceable.
Guess what? There have been generators built into bicycle hubs (within the center of the front wheel)for years.
Since 80% of the effort of bicycling is due to wind resistance, I'm inclinded to think that a hub generator is going to be a lot more efficient, than a wind turbine that will only increase drag.
Is it better than a hub driven light? No idea. The important point here is not to get strung out on the detail, but to be enthused that designers are even thinking about bikes and renewable energy. Instead of creating useless electric foot massagers, or disposable battery-powered razors. The glass half full thing. Looking for the positive, rather than shooting everything down cos it ain't 110% perfect.
Design thinking is incremental, it builds on the work of those who preceded. One idea sparks another. This light is not the be-all and end-all, but it might just spur another designer to conjure up an even better hub system.
Warren, in my post above (forgot to add my AKA), my point was that this design is fundamentally flawed, as stated above 80% of the effort in biking is due to wind resistance, therefore anything that would increase wind resistance (drag) is bad, bad, bad.
It would be like building an airplane with a skin covering made out of lead instead of aluminum.
I'm all for creative design and thinking outside the box, but not designs that are fundamentally flawed in concept.
speaking of creative design/new products, this site (in general) is great! I'd also advise checking out www.gizmag.com or www.makemag.com
Note: I have no association with gizmag or makemag
Yes, drag would be an issue, if it weren't mounted on the handlebars in front of the rider, who creates a lot more resistance than a fan does. And it wouldn't have the drawbacks of a generator, which can slow you down when starting from a full stop.
A couple of thoughts:
Hub generator powered lights are ideal and are available with capacitors (greener than lithium?)that store power while a rider is stopped.
However, they require a newly built wheel and are thus difficult and environmentally unfriendly to add to an existing bike.
I would say the more options for cycling powered lighting thats easy to install the better. And - a big, unsightly wind generator on a bike may inspire green thinking in casual observors.
1. Drag. Not more than a plain cardboard (10*10cm?) hold in front of you.
2. This thing can charge the battery from the wind while standing around, a dynamo can't.
3. 3.5V*0.07A gives ~0.25W...I use a 1W Luxeon on my bike, which is the least you need (IMHO). But this gadget is still better than nothing.
I'm a regular commuter by bike and I have tried a lot of different lights. This seems a good idea in principle, but the cheap hub generator I have on my bike at present produces 6 volts at 0.5 amps or 3 watts without adding to the difficulty of riding in a noticable way. This device produces 0.25 watts - one twelfth the power. LED or not, it's not much more than a toy and isn't going to throw a lot of useful light.
Bravo !
Voila un appareil très utile
pour les cycliste !
Quand sera t'il en vente en europe ?
I've been wanting one of these for a long time now. Yay!
I've had a toy windmill on the front of my bike and loved it. But clearly a lit up version would be far more practical, if not as cute.
And I don't care about drag. My bike weighs a ton (no, not literally), and I have a trailer with a gorilla strapped into it. Plus I'm fat. So the more effort I have to put into biking the better!
So, yeah... Yay!
Where can I get one in the US?
By integrating the fan generator with a modest wind-shaping shroud in front of the rider, the net gain in lowered wind resistance will offset the loss to drag, which as pointed out in a previous post, is normally not significant compared to body turbulance and profile relative to wind resistance.
Hi,
Can i buy the Wind-powered Bike Light, and if so, how?
Thanks
Laurence
i think this is a great idea. i'm sure a light powered by a hub is wonderful, but there it seems like there is less to install with this product, which is why there is a market for it.