Sturmey Archer X-FDD Dynohub/Drumbrake Experiments

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bairdco

a guy who makes cool bikes
Aug 18, 2009
6,537
264
63
living the dream in southern california
i've got a Strurmey Archer X-FDD dynohub/drumbrake set-up on my front wheel, and i'm working out a lighting system for it that will work with the higher speeds a motored bike provides.

first off, some notes on the hub itself...

the drum brake usually takes a little while to break in before it stops really nice. it's mostly a matter of the brake shoes seating in place. i figure riding along and pulling the brake lever slightly, causing some drag will help speed this up.

the finish and quality of the hub is excellent, and comes in 70mm and 90mm sizes, and is priced around 60-70 bucks.

it's drilled for 13-14g spokes, but it's easy enough to drill through the aluminum flanges to use bigger spokes. i'm running 11g spokes on a worksman 26" rim.

i talked to a rep who told me the hub can be run in either direction, as in, which side the brake arm is on, and from my experience, seems to be correct. i've run it both ways, so depending on where your lights go, or where your cables route, you can set it up to look clean.

the hub is a 6v, 3w AC power supply, and is usually fine for pedaling, but higher speeds increase the voltage and burn out lights. if running a headlight and a taillight, if one bulb burns out, the other will soon after, as the voltage is then directed to it.

other problems are:

when stopped, the lights go out unless a capacitor is used to store the voltage up. "standlights" are available, but expensive. there are a number of DIY methods i've found on the web.

another problem, or maybe just an irritation (for me and the guy who has to drive towards me, anyway,) is the flickering that LED lights make. if you use extra bright ones, it's a strobe light effect that goes away as you go faster, but if you're pedaling slow or pushing your bike, it's really annoying. regular bulbs don't flicker, but don't provide the brightness of LEDs.

the real problem is the voltage output of the hub.

rigging a voltmeter to the hub and taking a cruise, i found the voltage ranging (approximately) from 5-12v at pedaling to slow motor speeds, 18-24v at cruising speeds (approx 20-25mph) and maxed out at 52v at WOT (approx 45-50mph.)

yesterday, i had a 12v, 4w headlight only set up which worked fine all day, but blew out after i took it out at night to see how well it lit up. (unless a switch is added, the light stays on all the time the bike is moving, like mine was.) i'd say i got a total of 3 hours outta that bulb.

i had an LED in it, and that lasted 20 minutes.

wiring more lights in sequence (headlight, taillight, marker lights) will help to distribute the voltage, but at 50+ volts, nothing is gonna last too long without bridge rectifiers and other stuff wired in.

so that's the start of this thread. i'm hoping to make a functional lighting system without the use of batteries (or the sometimes it works sometimes it doesn't "white wire") that can be functional, reliable, easy to make, and above all, cheap.

if anyone has any experience with these hubs, fell free to chime in. i know Barely Awake has one that seems to work fine...
 

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chainmaker

Well-Known Member
Jan 19, 2010
2,634
69
48
Ma USA
Im following this one as Im not sure where Im going to go with My panther, I have a nice disc set-up but I would like a light for night riding that wont crowd the bike with storage batts or a bunch of sloppy looking stuff.
 

msrfan

Well-Known Member
Sep 17, 2010
1,808
120
63
Southern California
Hi bairdco, I've had some experience with these hubs. I'm using one at about 3000 rpm and it puts out 87 volts. Used a cell phone charger to regulate/rectify it down to 6 volts. It's one of my old units and the magnet has been removed without a keeper, so it has no output a lower rpms. Anyway you may experiment with the phone chargers. I bought a dozen or so with different outputs at the Goldenwest College swapmeet for 50 cents each. They obviously all have the same input. Too bad you don't want batteries. I use a small cluster hidden in my headlight bucket to stabilize and use when stopped. I also have a switch.
 

Scotchmo

New Member
Jun 23, 2009
217
0
0
Los Osos, California
bairdco,
The solution that will solve most of your problems is the same one that works with the white wire. Run the output of your X-FDD through a diode to a 6v battery. The battery acts as a voltage regulator. The battery limit’s the peak voltage, stops the flicker and allows the lights to work even when stopped. I use 2 AA rechargeable lithium batteries and they are working well.

Hook up the diode and battery and then use your meter to monitor your voltage while you ride. Do that for awhile until you are satisfied that the voltage stays within an acceptable range. Then you can remove the meter. That is what I did.
 

bairdco

a guy who makes cool bikes
Aug 18, 2009
6,537
264
63
living the dream in southern california
don't worry, i kinda left the party awhile ago:)

i ended up using a small voltage regulator. i forget what the exact specs are, i think it's good up to 45v.

so far the front light is still working. it's just a bunch of cheap LED's from a cheap flashlight. i tried hooking up a 12v car taillight for the rear, but the two wouldn't work together. it was either front or rear. i think the car light robbed too much power from the LED's.

it worked with another LED set-up in the rear, but i only used an LED light for testing. i didn't want to sacrifice it, 'cause i need it for my other bike.

one of these days i need to buy a few more of those cheap flashlights and hook it up, but i rarely ride at night so it's not high on my to do list, even though every time i ride my bike i think, "man, i should go get some more lights..."

i'm still hoping to make a fully functional system using capacitors and whatever else, and would like to incorporate a horn and brakelight, too, all running off the hub, but it's another in a long list of things i keep putting off.
 

The_Aleman

Active Member
Jul 31, 2008
2,653
4
38
el People's Republik de Kalifornistan
I'm sub'd to this thread and still trying to get this system figured out. I'm less than a rookie when it comes to designing electrical systems. I have 4 3.3v LED lights that I want to run off my X-FDD hub and a battery, but I don't know where to begin or what to do lol
 

discontinuuity

New Member
May 24, 2010
92
0
0
Colorado, USA
I've got a cheap battery powered tail light (about $10 from Wal-Mart) That works fine on my around-town mountain bike. It takes a couple triple-A batteries that last for almost 3 months. You could probably hook up some rechargeable batteries and the dynohub to a similar light, and put it in a more "retro" enclosure.
 

highlander9

New Member
Oct 15, 2010
74
0
0
Illinois
i've got a Strurmey Archer X-FDD dynohub/drumbrake set-up on my front wheel, and i'm working out a lighting system for it that will work with the higher speeds a motored bike provides.

first off, some notes on the hub itself...

the drum brake usually takes a little while to break in before it stops really nice. it's mostly a matter of the brake shoes seating in place. i figure riding along and pulling the brake lever slightly, causing some drag will help speed this up.

the finish and quality of the hub is excellent, and comes in 70mm and 90mm sizes, and is priced around 60-70 bucks.

it's drilled for 13-14g spokes, but it's easy enough to drill through the aluminum flanges to use bigger spokes. i'm running 11g spokes on a worksman 26" rim.

i talked to a rep who told me the hub can be run in either direction, as in, which side the brake arm is on, and from my experience, seems to be correct. i've run it both ways, so depending on where your lights go, or where your cables route, you can set it up to look clean.

the hub is a 6v, 3w AC power supply, and is usually fine for pedaling, but higher speeds increase the voltage and burn out lights. if running a headlight and a taillight, if one bulb burns out, the other will soon after, as the voltage is then directed to it.

other problems are:

when stopped, the lights go out unless a capacitor is used to store the voltage up. "standlights" are available, but expensive. there are a number of DIY methods i've found on the web.

another problem, or maybe just an irritation (for me and the guy who has to drive towards me, anyway,) is the flickering that LED lights make. if you use extra bright ones, it's a strobe light effect that goes away as you go faster, but if you're pedaling slow or pushing your bike, it's really annoying. regular bulbs don't flicker, but don't provide the brightness of LEDs.

the real problem is the voltage output of the hub.

rigging a voltmeter to the hub and taking a cruise, i found the voltage ranging (approximately) from 5-12v at pedaling to slow motor speeds, 18-24v at cruising speeds (approx 20-25mph) and maxed out at 52v at WOT (approx 45-50mph.)

yesterday, i had a 12v, 4w headlight only set up which worked fine all day, but blew out after i took it out at night to see how well it lit up. (unless a switch is added, the light stays on all the time the bike is moving, like mine was.) i'd say i got a total of 3 hours outta that bulb.

i had an LED in it, and that lasted 20 minutes.

wiring more lights in sequence (headlight, taillight, marker lights) will help to distribute the voltage, but at 50+ volts, nothing is gonna last too long without bridge rectifiers and other stuff wired in.

so that's the start of this thread. i'm hoping to make a functional lighting system without the use of batteries (or the sometimes it works sometimes it doesn't "white wire") that can be functional, reliable, easy to make, and above all, cheap.

if anyone has any experience with these hubs, fell free to chime in. i know Barely Awake has one that seems to work fine...
Hi, I am doing a similar setup to yours, except I plan to run a Sturmey-Archer xl-fdd with 90mm drum on a 49cc HS 142F 4 stroke shift kit which hits top speed of 40mph. Do you think you can check how many volts you measure with the following loads: 250mA and 500mA. For 250mA, going 20mph. For 500mA, going 40mph.
However, I don't want you to deliberately risk your life for some science experiment, so this should be done strictly on a voluntary basis. You did take your measurements using some roller device, with the wheel stationary fixed on a jig of some sort, right? I mean how else could you have possibly paid attention to the speedometer and the voltmeter at the same time while you're going 45-50mph? Unless on a long steady wind you were able to conveniently measure. Anyway, we're trying to get this all figured out over at CPF so I can come up with an automatic switching circuit which yields the best possible voltage for the appropriate speed of the Sturmey hub. The thread can be found here.
 

bairdco

a guy who makes cool bikes
Aug 18, 2009
6,537
264
63
living the dream in southern california
i took my measurements at speed, with the voltmeter strapped to my bike. the digital readout is big enough to see while riding without me worrying about running into anything. i don't think any stationary system would work as well, and i'd rather get real-world testing, instead of a hamster wheel simulation.

this thread pretty much died out, because i found a small voltage regulator for a coupla bucks at an electronics store that's rated at 12v-45v.

the guy at the store said the lights wouldn't come on 'til i reached twelve volts, but they start strobing as soon as i push the bike forward.

i've got a headlight and a taillight rigged up from cheap Harbor Freight flashlights, and then a battery operated brakelight. i still don't have a "standlight" that keeps the lights on when i'm stopped, but i don't ride at night much anyways, so i don't really worry about it.

my opinion of these dynohubs, is that they look great, stop reasonably well, and are a well made product, but the lighting results are easily duplicated with some cheap flashlights, a soldering iron, and some triple a batteries, so my interest in them has waned.

(edit) i just skimmed through the thread you linked. you're waaaay more involved in it than i was. i just wanted my lights to work and took a tesla mechanical approach to it, not a quantum physics richard feinman theory...
 
Last edited:
Jul 15, 2009
594
1
0
waukegan IL. U.S.A.
I have the same hub ,set up with a twin batt. And small ciruct board.
Basicly three blocking diodes , one on white wire and two on board.
This takes the ac from both wwire and dyno and charges batt.s each batt. Run s it's own light ,so no blow out issues . The bulbs seem to run a lot longer on dc vs ac and don't flicker any.
The hole set up was about thirty bucks ,i got everthing at radio shack and batt. Plus
The down side is all the extra wires and hiding a batt box somewere ,but sure works good
http://db.tt/iLzqisQ pic of board before soldering.
The front brake is well worth all the effort ,the all weather proformance is great. And there hub brake w/o dyno only a few bucks cheaper?
If you have a springer front fork ,this is prob one of the best brake setups you can use
Not haveing lights is the one thing the local LEO's seem to care about.
 

bowljoman

New Member
Aug 7, 2010
370
1
0
Wa
but the lighting results are easily duplicated with some cheap flashlights, a soldering iron, and some triple a batteries, so my interest in them has waned.
Enjoy the trips to get new batteries, or the curses when you forget to recharge them, or the less than spectacular performance at the end of their life.

I did the battery route for a year and will never go back. I even prefer the bottle generator to the batteries.

Rechargables/capacitor + dynamo + high output leds rule the night.
Having your batteries and flashlight is only one step away from perpetual light.
 

bogyman57

New Member
May 19, 2011
25
0
0
66
Minneapolis, MN
Now that Super/Ultra Capacitors have dropped in price...

Have any of you investigated that area?

I'm having the same "strobe" problem...

Typical "Bullet Headlight" conversion: Cree XM/L T6

I thought it was a grounding issue, but after I had isolated the Cree LED from the frame - the strobing remained...

It's already got the required recifier & v-reg, so I'm baffled...

Field Effect from the engine maybe?

Any help here boys?
 

RawRaw

New Member
Jan 12, 2013
7
0
0
Los Angeles
Now that Super/Ultra Capacitors have dropped in price...

Have any of you investigated that area?

I'm having the same "strobe" problem...

Typical "Bullet Headlight" conversion: Cree XM/L T6

I thought it was a grounding issue, but after I had isolated the Cree LED from the frame - the strobing remained...

It's already got the required recifier & v-reg, so I'm baffled...

Field Effect from the engine maybe?

Any help here boys?

how did you connect the cree xml t6 to the dynamo hub!??!?! I have both and i am tired of charging the battery..
any suggestions?
 

bowljoman

New Member
Aug 7, 2010
370
1
0
Wa
I get strobe under 10 mph.

I split the ac into two legs. 5v regulator make a half-wave rectifier and then two CREE leds in parallel forming a second half-wave rectifier in the opposite phase of the regulator.

Here is the diagram I use.

Once you have cree LEDs in hand you can complete the system with a trip to radio shack. I seriously recommend this circuit diagram for night riding. I have four running lights in the back, two Crees up front. I added a cheap headlight/red flasher for redundancy.

Before I came up with this system, I had a malfunction, and found myself in the dark. Now I wont go out without a spare headlight anyway...



I get HELLA STOBE like this under 10 mph. Higher than that I never notice strobe effect of half-wave A.C. running through the crees.

You can put a battery in parallel. Even if it is dead when you start riding, 50 yards later you will have some standing-light. The 6v hub KILLS a 12v bottle generator for performance and reliability.


Have fun!