Led powered Bicycle light(that runs of dynamo)

LED Flashlights – General Info
1

Hi everybody,

Im a great fan of cycling, and also a fan of bright flashlights.

My bike has nice led lights in the front and rear. Both are powered by dynamo that sits in the axle of the wheel.

But the front light is only rated at about 80 lumens. Most lights on sale are around this number. the best reviewd light is 90 lumens and about 140 euros.

My question is: Why is it not brighter? Is there a problem with power. I guess more power means more resistence from the dynamo, but still I cant understand why there are no 400 lumen lights on the market.

2

Usually the Shimano Nexus hub alternator is rated only 3W at 6V
It might be possible to consume a littlebit more, but i’m not sure by howmuch.

3

I know there is a device that plugs on to your dynamo that lets you charge your phone or powerbank by USB. So I dont think power is the problem.

4

6V, 3W equals 500 mA
Also the output is unregulated and AC
The best thing is to use a rectifier and a big elco, which will lower the output voltage but it will give DC current of around 4,6V
With an efficient triple setup you can easily gain Lumens, but dont expect miracles.
I think you can get around 250-300 Lm with a triple Samsung LH351D

5

A plan that I never carried out was converting an old bicycle front light (the classic dutch style) to MT-G2, indeed direct drive with a rectifier and chunky capacitor to smooth out the AC. I even bought a fitting led reflector for it as the stock incan reflector is optically incorrect.

I never carried the plan out though. And I agree that a 3V led will be more succesful than a 6V led.

6

I guess money is a pretty big object. They dont use fancy leds. Maybe there is room for something new;)

7

Would be nice to have a more powerful light, on a really dark road I can see where im going but brighter would be better. Its a pretty simple setup. You could even use a 18650 inbetween the light and dynamo to keep the current more stable.