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Reelight Bike Lights Powered By Magnetic Induction

Reelight (Images courtesy Reelight)
By Andrew Liszewski

Daytime running lights on cars and motorcycles have been shown to increase visibility of other vehicles resulting in less accidents. Since bicycles share the same road space it makes sense for them to have similar safety lighting. Reelights are the world’s first battery free bike lights that function at no extra cost to the user. Typically a dynamo is used to power a battery-less light but they require friction from the tire to spin a generator which means extra effort on the part of the rider. (Not a lot mind you, but I’m sure over time it adds up.)

Instead, the Reelight uses a set of 2 magnets that mount on the spokes of the bike tire. As the wheel spins the magnets pass the light which is mounted on the axle in a fixed position. Inside the light there’s a wound copper wire that in conjunction with the passing magnets produces an electrical current powering the LEDs. The light also includes a capacitor that will ensure it’s always on even when you’re not pedaling like when stopped at a traffic light.

The Reelight SL120 bike light kit which includes a white head light, a red tail light and 4 magnets is available on the company’s website for about $53.

[ Reelights ] VIA [ Smart Stuff ]







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  • dmills

    There is a cost to the rider, wieght and areodynamic drag (friction)

  • Felix

    There is also magnetic Friction because the energy for the Light must come from extra force applied on the magnets, but like the weight and aerodynamic drag the effekt should be nearly zero.

  • Dan

    Of course there’s a cost to the rider – it’s exactly the same principle as the old dynamo setup. A magnet moving near a conductor induces a current and experiences a retarding force, this converts kinetic energy into electrical energy. In a dynamo, the coils (conductor) spin inside a magnetic field, whilst here the magnets move near the coils.
    Doesn’t anyone balk at reading claims of free energy?

  • Oliver

    Yeah, this is in no way the first. They had them at least as far back as 1952, if not earlier. http://www.sheldonbrown.com/dynohubs.html
    The only innovation is that this appears to be able to be mounted as an add-on to an existing hub – whereas the originals were part of a stand alone-hub.
    The other trade off, is that the light is fixed to the axle… which sucks

  • Ole

    These have been out in Denmark for about a year. Friction is near zero. You really don’t feel it when riding.
    Having them fixed is a positive thing here, as it would take someone a whole lot of time and energy to steal them.
    Another really great thing about them being fixed is also that you ALWAYS have them on your bike. No more forgetting them and no more forgetting batteries.
    It’s a cool commercialization.

    Cheers!

  • NateTheGreat

    This is by no means the first magnet on the spoke design either. The “Red Alert” by Leader Sports operated by a nearly identical mechanism…and a lot cheaper.

  • http://bicycletronics.com GadgetGuy

    This looks great because once it’s on, it’s on, you dont have to worry about forgeting it or having it stolen.