Originally Posted by
PlanoFuji
First, let me apologize for my earlier post. A more detailed review of your reference cite reveals that it wasn't as ridiculous as I first thought, though I do find the conclusions without adequate support.
Dynamo lights are not typically rated in lumens for a reason. The measurement is not useful and mostly an artifact of marketing. The lux ratings occur at a fixed distance from the light source (I believe 10 meters) on the ground in front of the light source. Using this the EDELUX is a 60 lux light (I believe), the most common are 40 lux (of which I have one and it meets/exceeds the brightness of my 400 lumen cygolite, with a better pattern). And I have recently also purchased a Luxos B which is rated at 70 lux and is brighter (with a much better light shape) then 800+ lumen commercial battery powered lights I have used.
The better dynamo lights publish a light chart that shows lux rating and light shape over a two dimensional space in front of the light.
I agree with some of the things you've said. My biggest gripe about diy is the optics, there just isn't anything out there that's optimized for road riding besides proprietary optics from dynamo light companies. If I wasn't going the DIY route, I would've just bought the Luxos U and be done with it.
FYI, I found some commercial battery powered lights from big major brands use identically open source optics available off-the-shelf (cygolite cateye cough cough). That would explain some of the very generic looking beams out there.
But yes, it is possible for dynamo hubs to drive setup like mine to 1200 lumens, but I have to be riding at 25km/h(on Shimano hubs)/28km/h(on SP dynamos) or higher to achieve that level.