Generator head and tail light

GoldenMotor.com

Dan

Staff
May 25, 2008
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Moosylvania
Think it would torch quick at MB speeds and duration. Could re-rig it with a larger drive wheel on the gen so it turns slower. But as it is "battery-less", think it would only be lit when moving. Big safety issue aside from being a pain in the butt.

Be kinda fun to experiment with, though.
 

Intrepid Wheelwoman

New Member
Oct 29, 2011
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Hauraki District, New Zealand
I've used vintage Miller and Lucas generator lighting sets on my trikes, but as they are low speed vehicles I've never had a problem with them. I've got a very old German moped generator lighting set amongst my bits and bobs and the generator is a much more substantial piece of kit as compared with a standard bicycle generator so I would think that care would need to be taken if you were planning on using that modern day bicycle lighting set. As Dan says you would need to modify the knurled drive wheel if you didn't want to end up burning it up.
 

electron

New Member
Sep 10, 2014
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Adelaide
I used a bridge-rectifier followed by a capacitor and then regulator to run LEDs instead of globes on my stolen bike.
Was thinking about doing something better on current model. When i get some bits and pieces together i'll get some info posted.
The gen. is rated at 3W and 6V AC, so can supply 0.5A. So if we can get 12 Volts out we can run 6 Watts of lighting and so forth. But the gens voltage varies with speed so we need some form of regulation, this is done easiest with DC. So the gens output needs to be rectified with a bridge rectifier and smoothed with a capacitor (guessing around 22000uF will do).
Now we measure the capacitor's voltage at the slowest speed we want full lighting (maybe just pedallin). Multiply this by 0.5 and that's how much power u can supply.
Now choose a front light or reto-fit some LEDs of about 90-95% of your total calculated supply power and source & adjust a DC-DC converter to match the voltages of the supply to the lighting.
I haven't actually tried the dc to dc converter, but hope to in the future. Last time I used a linear (3 terminal) regulator (can't remember the voltages) with heat sink, but i think i'm due for a more up to date solution.
Also, the wiring after the rectifier can lo longer be earthed to the frame. A 2 wire pair MUST be used.
Looking at generators and headlights ATM and have a couple 3W 11V LEDs (ebay, actually measured 11v to be too high, won't last), so i can get this project started, but it won't be really soon.
The remaining 5 to 10% is for the back light, more on this in the future...
 

electron

New Member
Sep 10, 2014
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Adelaide
If anyone interested can connect a bridge rectifier (single package makes it a lot easier) followed by a capacitor (10000 to 47000uF) 16V should do and measure the DC voltage at different speeds, i could get the ball rollin'.
Start off with the capacitor discharged, will measure 0volts as the capacitor will store the highest voltage for quite a while.
 
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electron

New Member
Sep 10, 2014
39
3
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Adelaide
A 6volt regulator such as LM7806 connected to the capacitor will work if u just want your globes to stop blowing. A small heatsink screwed to the regulator will help if it gets hot, but must be insulated from any other wiring and frame!

Or an LM317T for a specialised voltage.

I'm prob going to use a LM2576 for myself.

If u usea potentiometer to set the required voltage. Remove it, measure it and replace with fixed resistor for relaibility.
 
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ckangaroo70

Active Member
May 13, 2011
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Central Illinois
I have a generator light on my bike as well as a battery powered headlamp and tail light. Mainly the generator light is on there as a novelty or conversation piece, but it does work and would work as a back up emergency light I suppose if the batteries in my main lamp died. Might just want to keep the speed down when using the generator light. They probably wouldn't last heavy use, but I just think they are neat and I had one on a bike when I was a kid.
 

silverbear

The Boy Who Never Grew Up
Jul 9, 2009
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northeastern Minnesota
If you're planning to cruise at pretty high speed it is likely you'll burn out the generator. I have used several of these older 6V generators with good results. They will burn out incandescent bulbs at even moderate motored speeds, so LED's are the answer to that. I cannibalize little 9 led units, removing the batteries and solder wires. LED's are positive-negative sensitive so if wiring it up one doesn't light things up, try it the other way. In spite of normally being powered by 4.5V of battery power the LED's seem to be tolerant of some voltage variance. I haven't had any problem with burning out the LED's. A dab of grease at the business end of the bottle generator is a good idea, too.

I have tinkered with the idea of wiring in a little battery box so that when the bike isn't rolling you could still be lit up. Also did some investigating of capacitors to store energy long enough to keep the lights going while stopped. Some front hub generators are set up this way, or so I'm told. A capacitor might be worth investigating. The old 6V generators are easy enough to come by on old bikes, ebay and such.
SB
 

redneck82

Member
May 25, 2014
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concord, nh
not bad, but the best and brightest i've found so far (for head lights anyway) is the cree xml2 5000 lm... as far as run time, the one i had on my last bike (stolen) would last me for a good 40+ miles of riding... and omg this lil bastard is bright! easily as bright as a car's low beams if not a lil bit brighter...

i've yet to find a tail light that i really like, but this is what i've found to be the best and brightest
 

curtisfox

Well-Known Member
Dec 29, 2008
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minesota
How about mount it to the motor somehow so when you stop it would keep the lights going.One could gear it so it wouldn't burn up,run a small belt. I used to go to hydrolic store and get O rings for humidifier belt worked good, about a 1/8"thick...........Curt
 

silverbear

The Boy Who Never Grew Up
Jul 9, 2009
8,325
670
113
northeastern Minnesota
What I've been intending to do is to hook up a capacitor to store up a bit of juice for when the bike is stopped. I don't know how long a capacitor would be able to power the lights, but if for a minute or two that would be enough until you got rolling again. Also it might be a good idea wiring in a small set of batteries for an emergency situation such as the mechanical failure of some sort (like a flat tire) where you can't ride the bike, but still need to be seen by others sharing the road.
SB