Batteryless LED Kit



Hey all,

I'm pretty new on here, so I'm not sure that I'm putting this in the right place, but here goes (moderators, please feel free to move thread).

So, I ran into a pretty cool setup online the other day, and I didn't see much of anything posted on MBc about it yet. The website is at

It's an electromagnetic generator (NO batteries needed, and NO friction/drag on rim) for 5 LEDs. Two white ones in the front, and three red ones in the back. With the addition of a switch, it can also have brake light functionality, which is cool. The product looks really neat (they have a video on their website), and I think I'm going to order some for my build.

The concept is that you mount two magnets on your spokes that rotate in close proximity to a coil/ball magnet setup mounted on your bike frame. When the spoke magnets pass near the coil/ball magnet, it causes the ball magnet to rotate within the coil. From physics II, this rotating magnet creates a changing magnetic field, which induces a current in the surrounding 500-turn coil. This charge is stored on a capacitor, which can power the LEDs for up to 5 minutes continuously.

What do you all think?

Really enjoying exploring this forum!


az cra-z

I used a similar setup that was a rear light only about 20 years ago, it seemed to work OK. It had a single magnet on the wheel and an inductive coil that fired the light just once per revolution (no power storage capability). Personally, though, I hate seeing white blinking lights coming at me while riding.