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Old 01-15-14, 01:58 PM   #1
Narhay
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Sturmey Archer Dyno Headlight LED Bulb Selection

http://www.bikeforums.net/showthread...-Superbe/page2

Down the page I have photos of the headlight. I'd like to throw in some 6V (E10 base, I believe) LED bulbs that would work with the dynohub. Anyone have experience with compatible bulbs?
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Old 01-15-14, 02:16 PM   #2
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back in the day there were just Incandescent bulbs .. and the wattage split the power output [6 volts

3 watts total] ... 2.4 w load in front 0.6w in the back , if a headlight only . the bulb has to be 6v&3w

Now a days the brighter LEDs put out Heat, and so need a heat sink to have any longevity..

that is in the design of the headlight unit as a whole..


FWIW, IDK even if the output on those old hubs is DC or as the newer ones AC, alternators.

to know .. access an Oscilloscope, and watch the display. http://en.wikipedia.org/wiki/Oscilloscope

either its a line or a wave .

I'm thinking they are flashlight bulb LED substitutes, in that situation
the battery power out put is DC and does not spike with speed changes
but declines steadily as the battery is drained ..

Last edited by fietsbob; 01-15-14 at 02:27 PM.
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Old 01-15-14, 02:52 PM   #3
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According to "Gentleman Cyclist" you need a "1 watt, 50 lumens, screw base LED with 2v to 9v operation."
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Old 01-15-14, 05:44 PM   #4
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Don't you need a rectifier?
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Old 01-15-14, 06:04 PM   #5
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My understanding is the the SA hubs are multi-pole alternators which will output AC and require a bridge rectifier to produce the DC that an LED lamp needs; a regular incandescent bulb works the same with AC or DC. This should not be difficult to arrange but you will lose about 1.4V with a silicon rectifier, about half that if you can find germanium diodes, which will reduce the light output somewhat. The bridge can be wired in anywhere between the hub and the light. You may need to put a capacitor across the DC if the light flickers at low speeds. Here's a Wikipedia article which might be helpful: https://en.wikipedia.org/wiki/Diode_bridge
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Old 01-15-14, 06:32 PM   #6
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For simplicity's sake with the rectifier/diodes eating up some of the power, would the LED cast off more light (the reason for the switchover) or would all the modifications to it render output similar to an incandescent bulb?

Ideally either incandescent or LED replacement lamps would ramp up and down with brightness as I am going faster and not flicker on/off depending on how much power is getting to some LEDs which may need steady current.
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Old 01-15-14, 06:52 PM   #7
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Would something like this halogen work for you? For the price, it might be worth a try. It certainly would be easier than trying to build a rectifier and stuff it into your headlight along with a heatsink. I've messed around with that in the past and didn't care for the results. I wound up just going with a modern B & M "Classic" lamp which has all the conveniences of a modern light (including standlight). Your project looks to be very period specific, so I understand your reluctance to go with that option.
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Old 01-15-14, 07:22 PM   #8
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Don't you need a rectifier?
I believe the threaded LEDs have a rectifier built into the base.
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Old 01-15-14, 07:26 PM   #9
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Quote:
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Ideally either incandescent or LED replacement lamps would ramp up and down with brightness as I am going faster and not flicker on/off depending on how much power is getting to some LEDs which may need steady current.
I think in order to prevent the LED from flickering, you'd need a capacitor or something to supply current during the times when the voltage drops. The incandescent bulbs also flicker, but it's only noticeable at low speed. At high speed, the filament doesn't have time to cool between cycles. LEDs are either "on" or "off;" there's no cooling period analogous to what happens in an incandescent bulb.
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Old 01-15-14, 09:08 PM   #10
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I also got a SA dyno last year and first used my old filament lights from my old Ralieghs. Only lasted a few rides until the front one jiggled to death and the tail fried right after. Then I got 4 of those screw in LEDs mailed for $63.50 from Minnieapolis. They are 1W, so I had to screw around making something else to use up the 3 watts. I had no problems with that, but my little plastic tail light housing fried then 2 bulbs. Then the next day I finally figured it out a couple blocks from home. I stopped and took the cover off and the bulb was already finger frying hot. They are actually very little different in the heat production, only the base is what fries instead. So maybe it was because of not having that diode.

Now I have proper lights, Edelux headlight. far better light focus.
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Old 01-16-14, 07:35 AM   #11
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No personal experience, sorry, but I do have this LED bulbs for Dynohubs page bookmarked.
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Old 01-16-14, 10:29 AM   #12
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If you look on ebay you can find e10 screw base bulbs for lionel trains and other uses... they're pretty cheap and come in small bulbs and some bigger bulbs with multiple LEDS on them. I have some of the little bulbs that seemed to work with some old lights but it was a buddy's bike and I haven't seen the dude in a while so I dunno how long they lasted.
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