Friction generator

[loquin]

Keep this in mind:

• as others have said, bottle generators output is dependent on speed, and you'll burn out bulbs when you go too fast with them.
• The bottle generators don't last too long, as the 'bearings' can't take much in the way of side thrust. This means that, if you are adding a sprocket to one, you really can't use it as a chain tensioner - it would soon lock up...
• they're terribly inefficient. You can feel a noticeable drag when they press against the tire, even if you're not using the light.

There are some European designs that seem to work pretty well though - that are well built and reliable. You might look into them, instead. There are also hub dynamos - shimano and Sturmey-Archer come to mind. Not only do they avoid the road gunk issue, but, they are efficient, low-drag approaches that have less issues with overvoltage than the bottle generators. Plus, the Sturmey-Archer version comes with a drum brake...

 

[motorpsycho]

i too thought the tire generator would work...but, they will burn out FAST.
so here's what i did..
I used the headlight and the tail light that came with the generator/ light kit. (bought the kit off e-bay for like $15.00 or something)
I took the bulb out of the headlight, and got a small flashlight with 3 super bright L.E.D. bulbs in it for like $5.00 at wal mart. I put the 3 L.E.D. bulbs in the center of the chrome headlight reflector in a triangle pattern in place of the single 3 watt bulb. I got a battery holder for 4 AA batteries, and wired it up to an on/off switch from an r/c truck. the headlight works extremly well, and it's plenty bright to see at night. using the headlight lens that has diffusing lines in it, the light is spread out in front and to the sides pretty good. It isn't just a single beam of light out in front of you like a flashlight.
I did the same thing with the tail light, but it only has one L.E.D. bulb in it, and it's powered by 3 small watch style batteries and is wired to another r/c truck on/off switch. the L.E.D. and the batteries for the tail light came out of a small pen flashlight that i got at wal mart. (it cost like $3.99, it has 3 batteries in it, and it comes with 3 extra batteries)
sure, i have AA batteries and small watch style batteries that will go dead after awhile, but i made these lights last year, and i am still on the same batteries...and they are still very bright. L.E.D.'s draw very little voltage.

 

[Tango911]

with LEDs now days just seend like a cheap light weight light is the way to go instead of adding a generator to the bike. or how bout solar charges during the day and lights up at night ha ha.
i do remember the old generators tho, still pretty innovative.

 

[AussieSteve]

The problem with LEDs is that they don't produce enough light.
Even my current Cateye halogen light is only useful to about 25kph.
There's nothing like a decent battery, generator and reasonably-sized incandescent bulbs. ie 12V 18/18W dual filament or halogen.
My generator runs off the shift-kit jackshaft instead of friction drive, but the principle is the same, with lower friction losses.
The (dual) headlight I'm using has 2 x 12V, 18W/18W bulbs, allowing 18W, 36W, 54W or 72W.
Can almost burn a hole through anything that gets in the way. LEDs don't compare.

 

[Esteban]

BUT, I still like the looks of an old Raleigh 3 speed with factory light kit !! A CLASSIC !

 

[AussieSteve]

I don't care what my bike looks like, as long as I can see where I'm going.