SON SL wireless dynamo wiring woes
 

I have a new SON SL dynamo, with the wireless connector, and a new custom fork to match. I am trying to connect it to an Edelux II light. But I can’t figure out how it’s supposed to go together, and can’t find any instructions online or elsewhere.

How is the wire sticking out of the fork crown supposed to connect to the headlight? Any wisdom or can anyone point me to resources? Thanks.

the wire sticking out of the fork is the plus wire, the fork itself is the negative. I assume you have the upright version, which has a negative wire. You need to short that to the fork somehow. The upside-down version has a place to bolt the ground wire to, and that needs to be shorted to the fork somehow.

Probably would help if you posted a couple of pictures of what you have.

Don't forget that the dyno isn't going to work if the wheel is mounted backwards. You can see a contact on one side of the hub axle.

Here are some pictures. I’m puzzled as to what to do with the fork wire and with the wires coming out of the light. I notice there’s a little hole next to the wire coming out of the light—is that where I should connect the fork wire?

I’m a total noob- what do you mean ground it to the fork?

(Forgive the messy garage)


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The wire coming out of the fork should connect to the inner wire coming out of the light. The outer.bare wire coming out of the light should connect to the fork, although it's also possible that the connection between the light mounting lug and the wire light mount and fork will be good enough.

https://www.peterwhitecycles.com/schmidt-sl.php

Thank you!

Does that fork crown have bare stainless at the brake bolt hole? I think that means your light is going to be grounded through the light body and you just have to connect up the inner wire coming out of the light. If you had a multimeter, you could check the resistance between the body and the outer wire. If there is continuity, the outer wire isn't necessary. I generally like to use an actual connection with wires, but since the light uses the fork anyway, I wouldn't with an SL dyno.

Since you have the right side up version, it doesn't have a grounding lug. Shorting it to ground just means connecting the wire to the fork somehow. But I think once you put the light on the bike and connect up to the inner wire you are going to get light.

So, here's a conundrum. I connected the inner wire to the fork wire and spun the wheel, and I got light! Great. So I clipped the ground wire and applied heat shrink.

The light worked for 1 ride. Now it doesn't work! What would cause it to work one day then stop altogether?

And, more important: to fix it, do I have to connect the ground wire?

I have never worked with that light or that hub, but I have lots of wiring experience with old British motorcycles, etc.

Do you have an extra piece of wire that you can use to test it by holding one end of the wire to dropout or other ground point and the other end on the ground wire that you clipped? Yes, this requires three hands, one to spin the wheel. This wire would essentially be substituting for the ground wire that you do not have.

Can you reseat the hub in the fork to make sure both sides of the hub have good connections?

Is there anything that could be shorting the existing wire? Could the wire insulation be frayed and copper wire touching bare fork metal? Etc.?

Or, could there be a break in the wire somewhere?

Good luck with that. Sorting out dysfunctional electrics can sometimes take some time.

Make sure that the inside of the fork stays are clean so the hub makes good contact. Make sure that the area you use for the ground is bare metal and clean also. The coaxial cable coming off of the headlight needs one wire hooked to the wire coming up the fork and the other is the ground. The right side dropout is machined for the dielectric\insulator. it snaps in with three pins then the contact plate snaps in with three barbs. The contact plate has the wire connector on it. Mine brand new out from the bicycle shop would fall out everytime I removed the wheel. I have it shoe glued in. My fork has wire guides on the surface of the fork instead of a hole to hide the wire. I sent the wheel to Peter White cycles because I thought the dyno hub was not working. There was nothing wrong with the dino hub. When sent back I mounted the wheel and It worked perfectly.

I think you don't have good contact with the ground. Maybe at the dropout?

You didn't possibly reverse the wheel in the interim, did you?

Have you checked all of your connections with a meter?

What would cause a failure?
The obvious stuff... a break in the conductors or any short between the two conductors.
Get the meter out and check it out.
Report back when you are done.

Also... photos.
Photos provide info to the people you are asking for help.
A good photo will let us know if your solder joints are lousy or if the heatshrink was applied badly, or.... etc.

I've spent a career designing electronics, which means I've spent a lot of time trying to understand when my stuff isn't working. A lot of the failures can be very, very subtle! Parts come back from the customers with some generic note "doesn't work". A lot of times it works fine when I got it, and I had to spend a lot of time trying to induce the failure. Sometimes I couldn't find a way to make the part fail, but sometimes it took some very specific conditions for the failure to occur.
Finding problems in your lighting system may require the same sort of troubleshooting diligence.

Steve in Peoria

Most of my questions would be answered with a cheap multimeter measuring the resistance between the inside of the front dropouts and the light mount. I would do both sides, in case there is a short from power to ground. I have a spare multimeter I would contribute to the cause. Pictures of every connection along the ground path would also be very helpful.

Whenever I buy some dropouts for an sl fork, Peter White makes the shop get a contact plate for the brake hole. You're supposed to braze it on the the crown. I have a big pile of them, because I have always used a stainless crown. The other place where the ground can get interrupted is at the dropout if paint get on the clamping surface for the non-contact side. There are steel versions of the dropouts that come with a stainless contact plate that you are supposed to braze on. If any contact points have paint on them, that's going to make this system very unreliable.

I know some builders have a threaded stainless boss so you can attach the ground wire to the fork. Seems like overkill. But since the original idea was to use a series of bolted connections for ground, each one of those is a place where ground can be interrupted.

OK, so I've examined the connection between the light and the fork wire and taken pictures. I cut off the heat shrink to make sure the wires didn't pop out of the connectors... and, sure enough, they haven't. Still no light. There's no paint on the dropout plate, but I can take more detailed pictures. Everything seems to be properly connected.

I also turned the wheel around, just to see what would happen. The reversed wheel had a lot more resistance when spinning than the correctly oriented wheel. Any significance?

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I am pretty sure you should expect more resistance when you turn the wheel around the wrong way, it's shorting the hub.

You didn't address the fork crown issue, or I didn't understand it if you did. Is there a bare plate at the brake hole that the light bracket bolts to?

If you don't have one, get a multimeter. There are some okay ones that cost less than $15 on amazon.

I was at Lowes hardware store the other day, and was amazed at the variety of cheap and decent meters that they sell. Save money on shipping and send some sales tax to your city too! :)

Steve in Peoria (with two Fluke meters and one really cheap meter... which is good enough for this sort of thing)

The terminals all look clean and free of corrosion, which is good.

I will note that there are two crimps on each of these terminals. The first should be crimping the wire strands, and the second should be crimping around the insulation to keep it from moving...


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Presumably the heatshrink tubing was covering the outer conductor of the coax. I assume that these are connected to something at the other end? Or not?

Steve in Peoria

The last one I got was a Harbor Freight. Really cheap, but it works.

The edelux headlight has a 3mm coaxial cable coming out of it. I ran the center copper to the wire that comes up the fork. The copper on the outside just under the rubber jacket I used for the grounding wire. That other hole is for plugging the taillight in. The pictures are incomplete I would like to see a picture of the fork were the contact plate for the hub is.

That hub is an alternator and the headlight converts the power to DC electric. Orientation of the wires matters not as long as one of them goes to the hot and the other for the ground.

As Steve noted, Op needs to get a proper crimper and redo those crimps. Probably with new connectors. I am not absolutely sure the crimps aren't the problem. A multimeter would help.

Orientation of the wires does matter in this case. If the contact side of the hub is connected to the outside of the coax, then power is shorted to ground. It doesn't matter on a typical SoN. Shimano hubs also can have problems if the wiring is reverse, because the power can be shorted to ground. This is likely to show up later though, because it probably will take a while for anything to break through the paint and be grounded.

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Without using the other wire there is no ground and the headlight will not function. The headlight has to have its own ground to the frame to work. The hub only grounds itself to the frame by making contact on the inside of the dropout. The same goes if you setup a taillight. This is easier because the wiring harness has the wires already setup for this.

That's incorrect, the housing is grounded. Again, OP needs to get a multimeter to check where the disconnect is.

OK, I'll redo the crimp on that wire. (I actually did buy a crimper on Amazon, but it was terrible and unwieldy and not easy to use, hence the result.)

As for a multimeter, can someone explain exactly how I'm supposed to use it? Thanks for the help, everyone.

I have the Son SL on my Co-Motion Pangea Rohloff. Mine does not work without running the other wire on the headlight to a ground. I believe the OP should try that so the light can function. Peter White and Sinewave are the people I went to to get info on doing the wiring harness and hook up a USB charger. The bicycle shop decided that it was to complicated for them.

You say the housing is grounded: I believe the path is probably blocked by the headlight mount not having good conductivity. This is easy to test. touch a wire to the housing and bare metal On the frame while spinning the wheel.

I give up
 

I haven’t had a chance to get a multimeter but here’s what I did:

1. re-did the crimp on the main wire. Connected it and spun the wheel, no dice.
2. Moved the serrated aluminum washer so the bracket was up against the fork directly (see photo #1)
3. Cut off more housing to give enough length to the ground wire to connect it to the bracket. Spun the wheel, no dice.

Pictures of everything requested below.
https://cimg0.ibsrv.net/gimg/bikefor...93e0ba9b2.jpeg
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