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Old 12-02-08, 01:24 AM   #1
BradBB
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Generator hub+Dinotte?

I'm sure this has been covered before, but my search turned up nada. Is it possible to run any headlamp, like, say, a Dinotte 400L, off of a generator hub? I'm assuming the answer is "no" because of voltage inconsistency or something like that, but I also know nothing of electronics.
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Old 12-02-08, 09:21 AM   #2
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It's a fascinating idea. I wonder if a capacitor would address the line voltage concern with the hubs.
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Old 12-02-08, 01:10 PM   #3
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Some fairly simple circuitry would address voltage concerns, the problem is that your average hub dynamo puts out about 3W...and many lights need more power to put out decent amounts of light.

Provided my estimates are right, a 200L needs ~3.6W at full power, so you're not far short neglecting any losses in the conversion circuitry...you could probably run it for commuting and only need to charge once a month, but you'll still need a battery in the system to keep it running.
A 400L needs ~5.8W, so unless you're doing some epic rides (all night) where battery life is a concern, you might as well just run off the battery and save on the complexity.
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Old 12-02-08, 02:55 PM   #4
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most dynamo generator can produce up to around 500mA so only reach 3 watts. (6 volts x .500A = 3 watts).
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Old 12-02-08, 03:50 PM   #5
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A hub dynamo can produce about 11 watts with 6 leds in series. Check this out and look at the results.

http://pilom.com/BicycleElectronics/DynamoCircuits.htm



The only catch is that you are limited to .5 amps which is okay for LED in series.
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Old 12-02-08, 05:12 PM   #6
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Why dinotte? Just buy the LEDs and parts. I spent $35 on the parts needed (and $70 for the dynamo).

I'll add pics later.

Edit:

I used Circuit #8, also have enough parts left over for circuit #10. With 7 watt at 20km/h, LED can pump out 600 lumens worth of light, will pump out more when the technology advances.



The circuit is inside the steerer tube.


The bracket above the LED is the switch to be mounted on the handlebar with high, low, and off.
Two inside lens are narrow to shine farther, and two outside is medium lens.

You can build this with 4 single die LEDs such as Seoul P4 U-bin (probably the same LED used in Dinottes) or Cree XR-E R2, or you can go single 4 die LED such as Cree MCE (4 Cree XR-E in one LED). Few people have already done a generator light with Cree MCE, less exposure and more intensity.

I'll upgrade to an MCE-style when it can generate more than 1000 lumens at 7 watts (probably take another year or so for the technology to come out).

Last edited by mrbubbles; 12-02-08 at 05:35 PM.
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Old 12-02-08, 05:14 PM   #7
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Quote:
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most dynamo generator can produce up to around 500mA so only reach 3 watts. (6 volts x .500A = 3 watts).
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The only catch is that you are limited to .5 amps which is okay for LED in series.
Incorrect. Dynamo alone will generate more than 6 volts depending on speed. A proper circuit will draw more than 0.5 amp out of the dynamo.
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Old 12-02-08, 05:16 PM   #8
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If you know nothing of electronics, either: learn, don't bother, or get someone else to do it for you.
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Old 12-02-08, 08:10 PM   #9
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You folks really know your stuff! I didn't pick the Dinotte for any reason other than their reputation, as well as the tidy package. I respect the fact that many here have the knowledge and creativity to wire this from scratch, but the DIY aesthetics of some aren't my taste. Personal preference, I know, and I'm sure the performance of the lights speak for themselves. I'd like to see some more pics of various home-brew dyno light setups!
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Old 12-02-08, 08:33 PM   #10
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Peter White cycles sells some LEDs designed specifically for Dynos. In addition Harris Cyclery sells the Supernova which has a very good reputation ... albeit costly.

Read this article by Pamela Blalock on her experience with the supernova.

http://www.blayleys.com/articles/lights/page3.htm
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Old 12-02-08, 08:46 PM   #11
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The DIY aesthetics of some aren't my taste. Personal preference, I know, and I'm sure the performance of the lights speak for themselves. I'd like to see some more pics of various home-brew dyno light setups!
That I understand. I don't have access to fancy machineries, lathe, or $200,000 CNC machines. I'm making due with a hacksaw and drills.

Here's two posted on other forums, both using Cree MCE, 500 lumens max with dynamo.



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Old 12-02-08, 09:33 PM   #12
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If you like the Dinotte, you might like these DIY:
http://forums.mtbr.com/showthread.php?t=368896

Here's another a good looking, simple DIY light:
http://forums.mtbr.com/showthread.php?t=407160
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Old 12-04-08, 01:07 PM   #13
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I'm wondering if anyone could help me with some circuitry. How can I limit the power from a hub dynamo so it won't destroy an LED lamp? I'd like to take one, two or three cheap LED lamps such as these, each running a 3-W luxeon LED, that are supposed to be powered by 3 AAA batteries each, and run the appropriate number (preferably two of them), as well as an LED tail light, off my hub dynamo.

Don't worry, there's enough power; my bike has a 16" wheel with a 3v Nexus hub dynamo, which now powers a 12v 5w halogen bulb very nicely, along with a 12v LED light (it's a car part, from pep boys or something). The rear light is totally satisfactory, but the halogen bulb doesn't put out as much light as I'd like. It's not under-powered; but LED's could give me a lot more light. And if done right, they wouldn't fry out every six or eight months.

I can solder together homebrew LED lights well enough, I've done several of them successfully; but cannot design the circuitry. I know I need a bridge rectifier; but what else? Suggestions?
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Old 12-04-08, 02:13 PM   #14
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Circuits are here.
http://www.pilom.com/BicycleElectron...moCircuits.htm #8 and #10 works really nicely.

Don't bother with Luxeon LED, they aren't that bright. Go Cree XR-E Q5/R2, Seoul P4s, or Cree MCE. Available at Dealextreme.

http://www.dealextreme.com/products.dx/category.917
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Old 12-04-08, 03:53 PM   #15
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If you are interested in adding a stand light this thread is very informative :
http://www.candlepowerforums.com/vb/...d.php?t=210602
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Old 12-08-08, 09:36 AM   #16
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Incorrect. Dynamo alone will generate more than 6 volts depending on speed. A proper circuit will draw more than 0.5 amp out of the dynamo.
I stand corrected, not an electronics guys. I thought dynamos were constant current, so that's why LEDs would be safe.
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Old 12-10-08, 05:21 PM   #17
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I really want to do a diy system, but from looking at the MTBF and candlepower forums, it breeds a sickness where no light is good enough once a new emitter comes out. That being said, I probably will build one soon.
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