himespau 

Anybody use (or hear of) magtenlight? https://www.magtenlight.com/

Seems like an interesting idea, maybe better than bottle generators, but cheaper than replacing a wheel with a dynohub.

I doubt their claims of no friction (energy has to come from somewhere), but it looks like it might be a good solution to an always on backup light to go with my magicshine for night riding if it works.

Looigi

There is electrical drag from magnetically transferring power from the wheel to the light, but there is no drag due to friction. Same with dynohubs pretty much. Bottle generators not only have electrical drag but added drag due to friction of the roller on the wheel.

15 Lux isn't much. There's another company out there in the EU I believe and reported in the forum a month or so back that has a similar technology, basically using eddy currents in the rim to pull power for lights.

himespau 

Yeah, I know there's no actual rubbing friction, but you'd think that there'd still be some (minimal) force required to break each magnetic attraction. I mean there's no such thing as a free lunch, right?

I don't know how lux converts to lumens. Is that half as bright as my supposedly 900 (but really more like 4-500) lumen magicshine? A tenth?

Are you talking about the reelight?

Just looking for an affordable battery free lighting solution (to go along with my magicshine as a complement and to help me limp home if my battery dies) without replacing a wheel with a dynohub. Right now I have a fairly decent cateye (battery powered) as my backup, but was just looking into ways to move away from battery power. I suppose going with a dynohub isn't the worst idea in the world, but it looks like decent dynohubs with low drag start in the $100 range and then I'd still have to buy spokes, a rim, put it together and buy a light.

minisystem

Looks interesting. Seems like it uses the same technology as the Reelight, with the magnet mounted on the spokes, but this time a complete ring to provide continuous illumination rather than flashing. Also interesting is that it uses a rear-facing LED with a cutoff reflector, something the Edelux premiered a few years ago to great effect.

With respect to hub dynamos, I think people wring their hands a lot about the drag more than is necessary. I guess on a 1200 km brevet drag and efficiency start to matter. For the 10-20 km commutes I'm used to, I haven't noticed a difference between my $300 Schmidt and my $40 Sanyo, even with the lights off, which is considered to be the crucial statistic (there is a measurable difference though!). For a while (and maybe still) you could get a Sanyo H27 laced to a decent rim for $75 on eBay.

I own 10 hub dynamos, most of which aren't even on bikes, so I might be a bit biased...

Shimagnolo

One lux is equal to one lumen per square meter.
Lumens measures how much light is being *emitted*.
Lux measures how much light is falling on the target.

How the beam is focused changes the relationship.
For the same lumen rating, a floodlight puts less light on the target than a spotlight.