Electronics, Lighting, & Gadgets - Need help with dynamo + LED system

Howdy!

First time posting in this subforum, but after reading through many threads I know there's some folks with experience to share.

I'm looking into building my own light set, and so far my research has pointed me toward a single Cree or Seoul emitter powered by a Shimano DH-3D71 dynamo hub. The hard part has been nailing down how to go about it electronically. After reading through a few sites there seems to be no concensus on pucks versus direct multiple LEDs, techniques for a standlight, current protection, bridge rectifiers, etc.

I realize that there are many considerations for lights. Some folks need the most powerful lights possible, others are trying to do the most with the least and building on a tight budget. These are my considerations:


Emitter does not have to be the most powerful on market, just a good balance of performance/power requirements/longevity
Standlight
Space considerations limit me to one emitter, possibly two if stacked vertically
Long bulb life
Automatic optical switch, integrated
Manual shutoff switch, remote
Flashing taillight w/standlight
Electronics will be homebuilt
Enclosure will be homebuilt
Quality componentry/design that lasts

Although my electronics skills are basic, I have a good friend that can fabricate whatever I'd need as long as I can give him a schematic. My skills lie in making the enclosure to heatsink properly and to fit the aesthetics of my project, which is a gentleman's city bike based on a Surly Steamroller converted to 650b. It has an 8-speed Nexus rear hub with coaster brake, so this obviously isn't a speed machine requiring the top performance in lighting, just something reliable, stylish and simple.

I apologize for the criticism as I very much admire what has been done with homebuilt lights technically...but have found quite a few to be lacking in aesthetics. I'm going for a clean, retro, old world look, so as few wires, switches and mounting brackets will be exposed as possible, hence the automatic optical switch and discreet manual shutoff. The enclosures will be integrated into homebuilt fenders, so long bulb life will create less hassle in changing them out, although I will design them to be disassembled...it's just not something I'd want to do regularly.

What I am asking for is a parts list, schematics for electronics boards needed, impressions of the relative merits of emitters, or any guidance at all. I already have the 650b dynamo wheel built and am already tinkering with ideas for the copper enclosure. Any electronics boards or taillight designs must be flexible enough for me to place them in any sort of enclosure I might come up with that fits the overall look.

So far I am liking the Circuit 12 design at www.pilom.com (http://www.pilom.com/BicycleElectronics/DynamoCircuits.htm) that fits into a headtube, but am confused as to whether it includes a standlight, provisions for a taillight or could be modified for optical and manual switches.

Thanks in advance for any input. :)

There is a good thread about standlights on Candlepower forums. And Pilom is the gold standard. You might also want to look through the mtbr forums diy section. If you are using a single led or two for that matter, you don't need Circuit 12. Circuit 12 improves low speed performance for a large number of emitters. At low speed, the dyno can't generate enough voltage to overcome 12-24v Vf of a large number of emitters. Circuit 12 does not incorporate a standlight.

I just got the Cutter XPE triple. 3 emitters on a 20mm board. Haven't decided which circuit to run it on.

Yes, I checked out that standlight thread at Candlepower Forums.

That's exactly why I'm confused! They didn't seem to come to any consensus that I could understand, and neither could my electronics whiz buddy.

Wow, that Cutter XPE is nice, though probably a bit much for what I'm doing. Seoul and Cree single emitters can be had for $5, and that sounds reasonable to me.

If you are looking for a "a clean, retro, old world look" you could start with some vintage lights and convert them to LED.

Here's one I have:

http://i37.photobucket.com/albums/e61/Unknown_Cyclist/c1ef_1.jpg

That's a cool looking light UC. :)

Unfortunately due to where I want to place the light (and my own vision of what that will look like) I'm pretty stuck on building my own. Finding a vintage enclosure that meets my parameters could be a lifelong search. I would however love to see how you achieved the conversion. Is it running on a dynamo?

After looking at that Cutter XPE that unterhausen linked to again...yeah, that could work. I hadn't realized it was such a small package, and that it included optics. I'm still at a loss as to how to go about powering it.

Finding a vintage enclosure that meets my parameters could be a lifelong search. I would however love to see how you achieved the conversion. Is it running on a dynamo?

It was going to, it's now an abandoned project.


After looking at that Cutter XPE that unterhausen linked to again...yeah, that could work. I hadn't realized it was such a small package, and that it included optics. I'm still at a loss as to how to go about powering it.

If you aren't after maximum light output at all speeds, things become much simpler.

The minimum amount of components and wiring you can successfully use is 1 rectifying diode and 1 LED - however you would be wasting 1/2 of the output from the hub.

After that you want four diodes in a bridge which you can then connect to any number of diodes.

Here's a rectifier:

http://i37.photobucket.com/albums/e61/Unknown_Cyclist/Rectifier.jpg

The capacitor is optional and is to reduce flicker at low speed.

The board is 1" long and designed for the space I have and simplified connection, ie. ac in one end, dc out the other.

It could be made smaller or the diodes could be soldered directly together with no circuit board and then covered in heatshrink with leads coming out of each end - for inline connection.

If you don't mind a less efficient option you can simply buy a bridge rectifier:

http://i37.photobucket.com/albums/e61/Unknown_Cyclist/Bridge.jpg

:)

UC, let's say I were to use the Cutter XPE triple. Would you recommend using your rectifier or one of pilom's designs? If so, specifically which one would accommodate a standlight and optical switch?

While I'm not concerned about building the brightest light out there, I do appreciate good design and getting the most out of whichever emitter is chosen. What would you do if you were building it for yourself and had plenty of time to do it optimally?

I put a light together for a roadster six months ago, and I had good results with lazyness. That is, I decided I didn't really need everything I thought I wanted at first.

I thought I wanted a dynamo tail light. Then I realized that LED taillights take so little power that I could run a rear stand alone with on an enclosed non-rechargeable battery for six months to a year. So no wires to the rear.

I thought I wanted something to smooth the beam so it wouldn't flicker. That is, a dynamo hub puts out power in a sine wave of increasing frequency. If you rectify with just a little bridge recitifier, you get flicker at low speeds. To get the nicest output you can make moderately complex rectifier that uses capacitors to smooth this. When I actually put the light together, though, I found that there was no flicker unless I was walking the bike or going insanely slowly.

I thought I wanted a standlight. But with the complexity of batteries and charging circuits, and running a rear battery powered light, I decided the benefits were quite small.

I thought I wanted several emitters. Then I realized that with a single cree XR-E (R2, WH tint) (I'm sure there are better ones now) I had more light output than people with 20W halogens had been riding on five years ago.

I thought I wanted a switch. I even chose an enclosure with one. But after setting it all up, I realized I couldn't feel whether it was on or off, and I liked that drivers would see me better with it on. So I leave the switch on 'on'.

So you can certainly make something complex that meets all your criteria, but you may decide it's not worth it. If you do, and just want something like I made, all you need is:

1 White power led
1 heatsink for led
1 elliptical (10/40) lens for led
1 bridge rectifier

Connect the two outputs of the dynamo to the two pins marker ~ on the rectifier. Connect the rectifier + to the led +, the rectifier - to the led -. Attach the led to the heatsink with thermal glue. Attach the lens to the led as appropriate. Put in housing. Done.

If you want a switch, it can go anywhere.

UC, let's say I were to use the Cutter XPE triple. Would you recommend using your rectifier or one of pilom's designs? If so, specifically which one would accommodate a standlight and optical switch?

While I'm not concerned about building the brightest light out there, I do appreciate good design and getting the most out of whichever emitter is chosen. What would you do if you were building it for yourself and had plenty of time to do it optimally?

Firstly, I'm not very expert at this, I'm relatively new to it.

My design isn't any different from Pilom's - it's just a basic bridge rectifier which is where all the Pilom designs start.

If I was attempting to do what you are saying, I would probably use a MC-E custom wired as a series/parallel network and connect it directly to the hub without any rectifier.

I haven't tried this myself but I am aware other people on here have run LEDs without separate rectifiers, the bonus is that there is no voltage drop due to the rectifier.

I'd then add a non-polarised capacitor if the light output needed smoothing,

A single LED at 500mA or less isn't going to provide much light, so if you are going to get above walking speed I reckon a 2S2P network could be ideal.

I haven't tried this myself yet, so I wouldn't recommend that you do.

It would give you max light at low speed with the minimum number of components and the smallest possible footprint.

:thumb:

If I was attempting to do what you are saying, I would probably use a MC-E custom wired as a series/parallel network and connect it directly to the hub without any rectifier.

I haven't tried this myself but I am aware other people on here have run LEDs without separate rectifiers, the bonus is that there is no voltage drop due to the rectifier.


This sounds like you're talking about using the power leds as the rectifiers. I was warned against doing this when I was researching my light, as the hub can put out a lot of power at high speeds which might be more than the leds can take in reverse.



A single LED at 500mA or less isn't going to provide much light, so if you are going to get above walking speed I reckon a 2S2P network could be ideal.


Three years ago I would have agreed, but leds keep getting better and better. I can see quite well with my single XR-E (R2). It's rated at 120 lm at 350 mA, so should be around 200 lm at 500 mA. Combined with good elliptical optics, it really can be good enough.

This sounds like you're talking about using the power leds as the rectifiers. I was warned against doing this when I was researching my light, as the hub can put out a lot of power at high speeds which might be more than the leds can take in reverse

Power or voltage ? The reverse voltage either pair of LEDs will see is the forward voltage of the other pair - which in turn is a product of the current through the LED.


Three years ago I would have agreed, but leds keep getting better and better. I can see quite well with my single XR-E (R2). It's rated at 120 lm at 350 mA, so should be around 200 lm at 500 mA. Combined with good elliptical optics, it really can be good enough.

I think you'll find you need a lot more than 500mA to get 200 lumens from a R2......

If you don't mind a less efficient option you can simply buy a bridge rectifier
I'll have to try that for my commuter. I'm getting a Sturmey Archer 3-speed/dynohub combo, and thus my dyno will be in the back. This means a taillight is a natural feature, since it will be right there. Then I can run a wire up to a single headlight LED. I suspect that will be plenty for my commute. Right now, I also use a helmet light. Or maybe I should just use 4 LEDs as my rectifier, but then my housings will not be as nice looking.

The triple XPE is going on the rando bike. Maybe I should just go the simple route there too. Not sure how much time I will spend going slow enough to worry about the low speed output.

Although the P7 and the MC-E both look like single LEDs they are actually 4 LEDs in one housing.

The P7 has all 4 hardwired in parallel.

The MC-E can be wired how you like.

I put a light together for a roadster six months ago, and I had good results with lazyness. That is, I decided I didn't really need everything I thought I wanted at first.

I thought I wanted a dynamo tail light. Then I realized that LED taillights take so little power that I could run a rear stand alone with on an enclosed non-rechargeable battery for six months to a year. So no wires to the rear.

I thought I wanted something to smooth the beam so it wouldn't flicker. That is, a dynamo hub puts out power in a sine wave of increasing frequency. If you rectify with just a little bridge recitifier, you get flicker at low speeds. To get the nicest output you can make moderately complex rectifier that uses capacitors to smooth this. When I actually put the light together, though, I found that there was no flicker unless I was walking the bike or going insanely slowly.

I thought I wanted a standlight. But with the complexity of batteries and charging circuits, and running a rear battery powered light, I decided the benefits were quite small.

I thought I wanted several emitters. Then I realized that with a single cree XR-E (R2, WH tint) (I'm sure there are better ones now) I had more light output than people with 20W halogens had been riding on five years ago.

I thought I wanted a switch. I even chose an enclosure with one. But after setting it all up, I realized I couldn't feel whether it was on or off, and I liked that drivers would see me better with it on. So I leave the switch on 'on'.

So you can certainly make something complex that meets all your criteria, but you may decide it's not worth it. If you do, and just want something like I made, all you need is:

1 White power led
1 heatsink for led
1 elliptical (10/40) lens for led
1 bridge rectifier

Connect the two outputs of the dynamo to the two pins marker ~ on the rectifier. Connect the rectifier + to the led +, the rectifier - to the led -. Attach the led to the heatsink with thermal glue. Attach the lens to the led as appropriate. Put in housing. Done.

If you want a switch, it can go anywhere.

That was some very sage wisdom: Don't get in over your head.

I wish I knew how many ambitious projects I've started only to drop them due to overcomplication. Thanks very much for the benefit of your experience.

So...is it possible to have a standlight using the simple bridge rectifier? If so how would I calculate the needed caps?

See the standlight thread over at CPF.
The easiest way is simply a supercap across one led (works ok).
Or if using more than 1 led you can charge the cap to a higher voltage and have it discharge through a resistor, (works well, brighter for longer).
Or you can use the dyno to charge a NiMH battery(s) and run an LED off it. Getting complicated now.

Personally, I think a commercial dyno light will do a lot of what you want and look good too.

Wow, not really getting the answers I need here.

Wow, not really getting the answers I need here.

You have pretty much listed every possible feature for a dyno light. Its a big ask!


Heres a nice looking one
http://www.candlepowerforums.com/vb/showthread.php?t=222866

Heres the standlight thread
http://www.candlepowerforums.com/vb/showthread.php?t=210602

Wow, not really getting the answers I need here.

How about some more precise questions ?

What exactly are you asking ?

I think you'll find you need a lot more than 500mA to get 200 lumens from a R2......

Well, they claim:

a) 120 lumens at 350 mA
b) light output increases linearly with current (up to about 1A)

And from this I calculate

c) expected output at 500 mA: 170 lm
d) expected current for 200 lm: 585mA

So my "200 lm" guess was too high; I should have said 170.

Or is one of a, b, c wrong?

Wow, not really getting the answers I need here.

Nobody has really spent the time to do what you want and deliver it to you as a clean package. If someone did do that design, the might keep it to themselves and sell it. Seems like there is some opportunity along those lines, but the top end commercial lights are pretty nice. Sorry to be the bearer of bad news.


Well, they claim:

a) 120 lumens at 350 mA
b) light output increases linearly with current (up to about 1A)

...snip....

Or is one of a, b, c wrong?
Is it really linear? And even if it is linear, my understanding is that the LED life will be badly affected at higher currents.

Is it really linear? And even if it is linear, my understanding is that the LED life will be badly affected at higher currents.

Have a look at the datasheet:
http://www.cree.com/products/pdf/XLamp7090XR-E.pdf

On p8 they have a graph of relative luminous flux against current. It looks close to linear. At 500mA it looks like it's 140% the flux of 350mA, which comes to about 170 lm.

Max current is listed on their site as 1A, and later on in the datasheet, on p10, they say: "based on internal long-term reliability testing, Cree projects that white XLamp XR-E LEDs will deliver median 70% lumen
maintenance after 50,000 hours of operation at a forward current of 700 mA."

Well, they claim:

a) 120 lumens at 350 mA
b) light output increases linearly with current (up to about 1A)
c) expected output at 500 mA: 170 lm
d) expected current for 200 lm: 585mA
Or is one of a, b, c wrong?

They are not linear.

R2:
40 lm at 100mA
80 lm at 220mA
120lm at 350mA
160lm at 500mA
200lm around 650mA
240lm around 850mA
280lm arond 1050mA
Note power goes up faster than current as the Vf increases.
Numers from JTR1962 "white lumen testing (http://www.candlepowerforums.com/vb/showpost.php?p=2412997&postcount=158)" thread on CPF
Will post link later.

The points we are interested in are 250 and 500mA as thats what you can easily achieve from a dyno. Thats 90 and 160 lm.

Thanks znomit. I found the thread you referenced:

http://www.candlepowerforums.com/vb/showthread.php?t=89607

it is a pretty amazing thread. jtr1962 has done a huge amount of testing.

Sounds like it's not quite linear, though it is close in the 350-500mA range.

I guess I need to revise my number down further from 170 to 160. Which is now pretty far from 200.

Qualitatively, though, I've found it definitely bright enough to see.

Nobody has really spent the time to do what you want and deliver it to you as a clean package. If someone did do that design, the might keep it to themselves and sell it. Seems like there is some opportunity along those lines, but the top end commercial lights are pretty nice. Sorry to be the bearer of bad news.

No problem.

What I was looking for was simply something that was proven to work and reliable. What I am gathering is that this is yet another complex hobby I don't need. No worries, we'll work out something. I was just hoping to save some time.

I put a light together for a roadster six months ago, and I had good results with lazyness. That is, I decided I didn't really need everything I thought I wanted at first.

I thought I wanted a dynamo tail light. Then I realized that LED taillights take so little power that I could run a rear stand alone with on an enclosed non-rechargeable battery for six months to a year. So no wires to the rear.

I thought I wanted something to smooth the beam so it wouldn't flicker. That is, a dynamo hub puts out power in a sine wave of increasing frequency. If you rectify with just a little bridge recitifier, you get flicker at low speeds. To get the nicest output you can make moderately complex rectifier that uses capacitors to smooth this. When I actually put the light together, though, I found that there was no flicker unless I was walking the bike or going insanely slowly.

I thought I wanted a standlight. But with the complexity of batteries and charging circuits, and running a rear battery powered light, I decided the benefits were quite small.

I thought I wanted several emitters. Then I realized that with a single cree XR-E (R2, WH tint) (I'm sure there are better ones now) I had more light output than people with 20W halogens had been riding on five years ago.

I thought I wanted a switch. I even chose an enclosure with one. But after setting it all up, I realized I couldn't feel whether it was on or off, and I liked that drivers would see me better with it on. So I leave the switch on 'on'.

So you can certainly make something complex that meets all your criteria, but you may decide it's not worth it. If you do, and just want something like I made, all you need is:

1 White power led
1 heatsink for led
1 elliptical (10/40) lens for led
1 bridge rectifier

Connect the two outputs of the dynamo to the two pins marker ~ on the rectifier. Connect the rectifier + to the led +, the rectifier - to the led -. Attach the led to the heatsink with thermal glue. Attach the lens to the led as appropriate. Put in housing. Done.

If you want a switch, it can go anywhere.

I can see some of your points. I can understand not wanting to hook up the rear dynamo light because of the hassle, though I personally prefer them (running wires is a one-time task, and you can't tell while riding if the rear light has run out of battery).

But saying the benefits of a standlight are quiet small is just insane if you ever ride on the road. Well...I guess if your tail light isn't dynamo powered it's not at bad. But with no standlight, you go from being visible to completely invisible whenever you stop - you know, when you'd be most likely to be hit because you're standing still expecting traffic to see you.

To the original poster, sorry I can't offer any real advice. I have seen manufactured retro dynamo lights, and I think my Lumotec Cyo is a fairly "clean" looking design. I'm just so impressed with both the light output and the shaped lense design I can't imagine any reason to build my own.

No problem.

What I was looking for was simply something that was proven to work and reliable. What I am gathering is that this is yet another complex hobby I don't need. No worries, we'll work out something. I was just hoping to save some time.
I wish someone had done this an published a board. Probably happen sooner or later.

I can see some of your points. I can understand not wanting to hook up the rear dynamo light because of the hassle, though I personally prefer them (running wires is a one-time task, and you can't tell while riding if the rear light has run out of battery).

But saying the benefits of a standlight are quiet small is just insane if you ever ride on the road. Well...I guess if your tail light isn't dynamo powered it's not at bad. But with no standlight, you go from being visible to completely invisible whenever you stop - you know, when you'd be most likely to be hit because you're standing still expecting traffic to see you.

To the original poster, sorry I can't offer any real advice. I have seen manufactured retro dynamo lights, and I think my Lumotec Cyo is a fairly "clean" looking design. I'm just so impressed with both the light output and the shaped lense design I can't imagine any reason to build my own.

I do appreciate your post and agree with a couple of your thoughts.

My main goal with this project is to have a "set it and forget it" type of rig. I do not wish to deal with dead batteries for the rear flasher, so it will definitely be wired to the dynamo and include a standlight. I also agree with your standlight position for the headlight. Going from bright to dark at night sounds dangerous, especially since this may be my only light source. I know it will be more difficult to build these features in, but once it's done, it's done. I'll be able to jump on and go.

Unfortunately I cannot use the Lumotec Cyo. According to Peter White, it is incompatible with the Shimano dynohub and requires bulbs that eventually burn out. I'm looking for a 100,000 hour LED solution precisely to avoid that issue. I'd also want to build my own enclosure anyway for aesthetics and durability.

I do appreciate your post and agree with a couple of your thoughts.

My main goal with this project is to have a "set it and forget it" type of rig. I do not wish to deal with dead batteries for the rear flasher, so it will definitely be wired to the dynamo and include a standlight. I also agree with your standlight position for the headlight. Going from bright to dark at night sounds dangerous, especially since this may be my only light source. I know it will be more difficult to build these features in, but once it's done, it's done. I'll be able to jump on and go.

Unfortunately I cannot use the Lumotec Cyo. According to Peter White, it is incompatible with the Shimano dynohub and requires bulbs that eventually burn out. I'm looking for a 100,000 hour LED solution precisely to avoid that issue. I'd also want to build my own enclosure anyway for aesthetics and durability.

I find your initiative intriguing and interesting, however, in the spirit of being helpful I believe you are completely and totally mistaken on that last part.

According to the official Shimano page:
http://bike.shimano.com/publish/content/global_cycle/en/us/index/products/0/nexus/product.-code-DH-3D71.-type-.html
Your hub (a Shimano DH-3D71) is a standard 6w 3 volt hub. I do not believe Shimano actually makes hubs to any other spec - some other company makes 12 volt hubs, but not Shimano. I personally have a Shimano Alfine hub which has the same specs - 6v, 3 watt:
http://bike.shimano.com/publish/content/global_cycle/en/us/index/products/0/alfine/product.-code-WH-S500-V-3D-L.-type-.html

Some sort of communication error perhaps? I can with great certainty state that the Lumotec Cyo does NOT require bulbs that burn out. Just take a look at the Peter White site:
http://www.peterwhitecycles.com/schmidt-headlights.asp
Under the Cyo it says "It uses a different LED and has a heavier heat-sink to keep the LED running cooler, so the already brighter LED can run brighter still."
Also from the same page "and because LEDs work for many thousands of hours without failing (unlike the 100 hour run times with halogen bulbs) some riders like to use LED headlights without a switch and just have the light on all the time."

Aesthetics-wise the Cyo is what it is, I like it but you might prefer something different. Durability-wise, I would think the waterproof casing it comes with would be more durable than anything you could build yourself at home, especially once you add in standlight features and everything.

But the big, huge advantage the Cyo has over a home-built solution is the optics. The light has a lense on it that is just *fantastic*. It only throws light onto the ground ahead of you where you need it. It doesn't throw light up into the trees, doesn't throw it way off to the side, it's just there in front of you and a little to the sides in case you're turning, and the beam has more light at the top (where it has to go farther) which gives a pretty even distribution of light on the ground right in the area where you're looking. With the exact same LED but no optics, I can't imagine you would get nearly the reach and visibility from the light. I just can't say enough how incredibly impressed I am by the beam pattern - I actually *don't need* another light to bike at night with it (well...to be fair I also *like* to have a helmet mounted light so I can point it while riding).

When you say that the light won't work with your dynamo and the bulb needs replacing, it sounds to me like there was a communication error somewhere and those are specs for a different, not Cyo light. Hope I'm being helpful.

When you say that the light won't work with your dynamo and the bulb needs replacing, it sounds to me like there was a communication error somewhere and those are specs for a different, not Cyo light. Hope I'm being helpful.

You certainly were being helpful, and you were also correct.

I just checked my information again and the incompatibility listed was for the Lumotec Halogen modified for the Schmidt hub. Peter says to not use it with the Shimano hub as it grounds to the frame.

I have no doubts your shared experiences with the Cyo will be helpful to someone else reading this thread, but I am still committed to building my own. I am not dependent on this one bike for transportation. If I were, I'd certainly consider a commercially produced solution. Since I do have the luxury of time...I'll stick with the plan. :thumb:

I can see some of your points. I can understand not wanting to hook up the rear dynamo light because of the hassle, though I personally prefer them (running wires is a one-time task, and you can't tell while riding if the rear light has run out of battery).

But saying the benefits of a standlight are quiet small is just insane if you ever ride on the road. Well...I guess if your tail light isn't dynamo powered it's not at bad. But with no standlight, you go from being visible to completely invisible whenever you stop - you know, when you'd be most likely to be hit because you're standing still expecting traffic to see you.


When I'm stopped, at least two of the following are always true:

1) dangerous things (other bikes, cars) are approaching only from the back
2) there are no cars (bike path)
3) there are street lights

So as my tail light is not on the dynamo I think I'm pretty safe.

It wasn't the hassle of rigging a dynamo powered rear light or running wires that got me to use a rear battery system. It was that I'd need to (1) build in standlight circutry and (2) have to worry about running it down and going completely invisible if I was stopped for a while.

This thread below might have the answers you need.

http://www.candlepowerforums.com/vb/showthread.php?t=203223

I do appreciate your post and agree with a couple of your thoughts.

My main goal with this project is to have a "set it and forget it" type of rig. I do not wish to deal with dead batteries for the rear flasher, so it will definitely be wired to the dynamo and include a standlight. I also agree with your standlight position for the headlight. Going from bright to dark at night sounds dangerous, especially since this may be my only light source. I know it will be more difficult to build these features in, but once it's done, it's done. I'll be able to jump on and go.

Unfortunately I cannot use the Lumotec Cyo. According to Peter White, it is incompatible with the Shimano dynohub and requires bulbs that eventually burn out. I'm looking for a 100,000 hour LED solution precisely to avoid that issue. I'd also want to build my own enclosure anyway for aesthetics and durability.

The problem with the Lumotec Oval Plus and the Shimano is not voltage or amperage, but simply the fact the Shimano hub is grounded while the Schmidt is not. So when one uses the Lumotec Oval Plus with the Shimano hub, the grounding prevents the light from working.


Peter White's warning goes for the Lumotec Oval Plus (i.e. the one with a halogen light bulb and a standlight). I know that the Lumotec IQ Fly and I think that the Lumotec Cyo are OK with the Shinano dynohubs. But anyway, there is a very solution to wire a "non-compatible" Lumotec Oval Plus with a Shimano dynohub: electrically insulate the headlight from the frame by installing it on a piece of pexiglass or flexible plastic tubing. On my daughter's bike, I have used a section about 2 cm long of EMT electrical tubing.


Finally, with regard to standlight or no standlight, I think it is essential in the back. I prefer to have one in front too, but unless I ride on well lit city roads, I prefer to have a small battery-operated LED headlight too (ex.: Planet Blaze). The standlight is no good when you need to fix a flat in the dark.