Batteryless bicycle lights, new kind dynamo

It's been ripped apart on this group before. The page does admit that it's not completely dragless, but shows quite a bit of ignorance about physics. If he's going from mechanical motion to LED's with fairly low loss he's doing well. If he's actually generating enough light to be seen then that's pretty good.

I suspect that he _is_ getting more efficiency at low speeds with his tumbling magnet idea, and it's pretty easy to beat the usual wheel-on-the-tire arrangement. I doubt that it'd light up the road like a good generator (I've always wanted a Sturmy-Archer Dynohub).

Hey, Conservation of Energy has finally been overcome! About time.

John

Congress just repealed it and Bush signed it, in case you did not notice.

I thought he was a Conservative.

John

Wow, we always wanted this kind of perpetum mobile. ... It won't slow me down ... ( Worldwide patents panding. ) Great. Can I order a 10MW machine ?

Rene

Thanks Tim, The usual wheel-on-the-tire got improved meanwhile. They are using brushless DC motors with rather high efficieny. When you're out in the nowhere where at certain wheather conditions it can be darker than in a cow, even high brightness 10W are not that much. The local bike store sells twin 10W beams for $100++

Rene

There was an article in one of the mech.engineering mags (Eureka maybe) this month on a neat product that fits inside the pedal, using a small generator and capacitor to provide lighting from the rotation of the pedal shaft.

They are right there. Where is there friction? Drag yes, but not friction. They do admit that on another page.

What one needs is a lighting system with a rechargeable battery and a generator that cuts in when the bike is going downhill or braking.

snip

month on a neat

provide lighting from

A bit OT, but the website in question has

in the top LH corner

any ideas?

martin