OK, i just got a Shimano HB-NX30 hub, a Lumotec Oval Plus and a 4D multi senso taillight, and i have a few questions.

1. does the hub have a voltage limiter in it?

2. does the hub become less efficient the faster i go?

3. what is the best way to hook up the light?

when i hook up the light (but do not mount the light on the bicycle and spin the wheel, the switch on the light works properly. when the switch is off, the light is off. when i mount the light on the bicycle, the switch DOESN'T work anymore. so i figure the switch is shorted out by the bike. the hub is grounded and the light is grounded.

4. is this expected behaviour? it seems "broken out of the box." i don't understand why it is designed this way. what am i missing? if everything is supposed to be grounded, then the switch seems useless.

i have a 2.4 watt bulb and a 0.6 watt taillight.

5. do i want to hook these up in parallel or in series? i think parallel.

6. if i want to add a second light, do i do that in parallel or series? i think parallel.

7. how does the motion sensor on the 4D multi senso work? i thought it came off of the energy pulses from the hub, but i disconnected it from the hub and it still came on when i started to ride home in the dark. that was unexpected, but i am glad that it works like that.
8. how long does the 4D senso multi stay on after there is plenty of light or the bike stops moving.

1. As far as I know, the NX-30 dynohub doesn't have a voltage limiter, it's the Lumotec headlight that has one. That's why you could mount two Lumotecs in series.

3. Fairly detailed wiring instructions are available on Peter White's site at https://peterwhitecycles.com/wiringinstructions.htm While that page was written for the SON, the same instructions apply for the SHimano. One small difference is that you will need to connect the loose wires from the headlamp into the connector provided with the dynohub.
See Shimano Service instructions at https://www.shimano-europe.com/cyclin..._pdf/2ST0C.pdf . From what I see, you probably have reversed the cables in the connector (the one that connects to the dynohub), and since the Shimano seems grounded, it means that when you put the light on the bike, you short it. Reverse the cables in the connector and you should be OK. BTW, check the top right illustration of the Shimano Service Instructions to see what I mean.

3, 4, 5. In theory, the contact to the taillight uses your bike frame as ground. On some bikes the ground is non-existent, but on many others, it's poor. Still, you need to make sure you connect the proper wire in its right place: i.e. the ground wire should be connected to the ground of the taillight and to the tab of the headlight that is the closest to the mounting bolt of the headlight.
BTW, the taillight runs parallel to the headlight, so its wattage (0.6 W) + the headlight wattage (2.4 W) total 3 W. The Zener diode in the Lumotec headlight clips the voltage at 3 V, so you won't fry bulbs. And it's essential to connect the taillight onto the tabs of the headlight (as shown on Peter White's site) so the taillight is also protected from overvoltage.

6. No. The second light will be in series. Since the Shimano dynohub is grounded, however, you will need to install the secondary Lumotec on a plastic or otherwise insulating mount such as the Chronometro knob to make sure you don't have faulty grounding.

How to connect. Use your imagination as well as photos from https://peterwhitecycles.com/dualsetupfork.htm and from Shimano's service instructions (top right figure again). You would need to cut the light cable where it enters the hub connector, splice it to 1 wire that goes to the secondary Lumotec, and plug the 2nd wire coming back from the secondary into the "light" side of the hub connector.
That way, current flows from the generator into the secondary, then back near the generator connector, then into the "light" side of the primary headlight (and taillight), then back into the "ground" side of the generator. When you switch the secondary off, you actually short it so only 1 headlight is working.


7, 8. No idea. My two setups use only generator-based headlights. I use battery taillights, which avoid complex wiring issues, especially since I often tow a trailercycle and/or a child trailer.

OK, your post make a lot of sense. thanks.

the shimano instructions say that you shouldn't touch the connectors, because there might be high voltage coming off of the hub. so, you're right, there is no regulator in the hub itself. all the regulators are in the lights, so that's why you want to have them in series. makes sense.

the wire from the lumotec lite is coax. i assumed that the inner wire is positive and the outer is ground. i am very sure (OK, check when i get home) that i put the outer wire to the ground position on the hub. the outer one is the one that the switch on the light is connected to.

hmmm....

so the more i think about it, i assumed that the outer wire should be ground...

but, if the power coming off of the hub is AC (which i just realized that is should be), then which wire is the grounding wire just has to be uniform.....

i'll go back and make continuity measurements on the light again, taking into account that there may be a couple of diodes in it.

thanks a lot!!

mark

There are some interesting references at this web site: https://www.audax.uk.net/lights/

How are you running the wire to your rear lamp?
SKS fenders are suposed to have an integral electrical connector. I followed the advice of Tony Oliver in "Touring Bikes", and glued a wire to the inside surface of a plastic fender, which I connected to my bottle dynamo tab. The earth runs through the fender stays.

see picture for a better understanding of what i am thinking.

so, hooking up the taillight to one of the positive tabs or mounting the light to the bike effectively shorts out the switch, which is why it is always on when i mounted the light.

Something seems wrong. i think that the switch should be on the positive tabs. i don’t get it.

well, i’m just going to reverse the wires down at the hub, and hook the rear light to the ground tab.

thanks for all the help.

well, switching the wires didn't help. the switch just shorted out the hub.

when i turned on the switch, you could feel the notches in the hub, but since there was no way to dissapate the energy, the wheel didn't really slow down.

i think the lumotec and the shimano were not made for each other.

Have you tried to connect the Lumotec by itself, without the taillight ?
(Don't spin it too fast, however, because the zeener diode won't limit voltage adequately unless you have either a 3 W headlight or the taillight attached.)


What switch do you have?

The installation I have on my commuter is with the Dynohub and the standard (round) Lumotec with a built-in switch, rather than the light-controlled switch sold by Shimano. No problems with the instructions provided earlier.

If your setup uses the Shimano switch, it should be on the live wire, not on the ground. Anyway, to try to pinpoint the problem, install the headlight on the bike, but wire it directly without the switch to see if things work.

Another factor to note: one model (sole model?) of the Shimano switch is light sensitive. Make sure light doesn't play a factor...


Finally, unless you spinned the hub for a long time, it should still work. Don't connect anything on it and check with a Voltmeter to see what happens.


P.S. I'm afraid it might be a good idea to get in touch with an electrician or at least someone who knows a bit...

Today's one of those days on which I'm extremely happy these forums are here. I got a Shimano DH-3N70 Hub Dynamo and Lumotec Oval Plus for Christmas. I've been setting it up today, but having this same problem: when off the bike the switch works fine, but as soon as I mount it the switch no longer works and it is always on.

From the forums I got the following key pieces of information: 1) The Oval Plus is grounded to the frame; 2) The switch on the Oval Plus is on the ground side of the lamp; and 3) Unlike the SON dynohubs, the Shimano hubs are grounded to the frame. As a result, the Oval Plus when connected to a Shimano dynohub will not work correctly if connected to a metal bracket.

I've seen suggestions here and there that to get around this you can mount in on the handlebars or add some sort of insulating layer. Neither of these is very satisfying so I took a harder look at the lamp; I think all you have to do is remove a screw that connects the ground of the lamp to the terminals where it makes contact. As far as I can tell, the screw serves no other purpose (i.e. I think this IS its purpose). I'll link a few pictures below.

1) This picture just shows the whole lamp. On the left side you can see that where it bolts to the bracket there are large metal contacts:

https://mypage.iusb.edu/~hpscott/Bike/BM_Full.jpg

2) The following two images show the underside of the lamp. Notice the screw on the terminals for adding a tail or secondary lamp (in the second image it has been removed). Notably, this screw does not hold the terminals in place, and from what I can tell doesn't do anything other than make electrical contact to the metal contacts for the lamp body (as shown in BM_Full).

https://mypage.iusb.edu/~hpscott/Bike/BM_In.jpg
https://mypage.iusb.edu/~hpscott/Bike/BM_Out.jpg

After removing that screw my lamp now works as expected: when the switch is off the lamp is off! I strongly suspect that this is the intended use for the screw, but apologize in advance if I'm mistaken (or if some else has already posted this information!). If anyone knows a reason why this should not be done, please post ASAP and I'll delete this post.

sorry to resurrect, but i had the same problem with my setup as derailed. taking out the front screw fixed the problem. yay bike forums.

Thanks for posting; I'm glad to hear someone benefitted from this. From what I can tell, the Lumotec Oval Plus is now very hard to find (perhaps because of this issue?). It's too bad, however, because the metal toggle switch is very nice.

-D

P.S. You should probably cover the hole, especially if you don't use fenders. A simple way to do this is to thread the screw back in, but use a washer or something to keep it from making the contact. (One last thing: after figuring this out, I realized that the instructions actually recommend doing just this... it's just hard to understand initially because it is a fairly poor translation)

Cool, thanks for the info, and for still hosting the pics. I'll remember this when I get back to the States and try installing my new LED Oval Senso Plus and Selectra Plus taillight (bought 'em at a shop here in Germany).

Well, I did the installation, and did not remove the screw. So far, it's working great.

What I don't know is whether the taillight is still isolated from the bike ground -- it probably is, actually, because I don't think that its screws act as a ground. If they were, there's still several layers of paint between the taillight, the headlight mount, and the hub itself.

I believe this issue only occurs with the Oval Senso Plus (with an incandescent bulb). I don't know if you can even still buy this model any more.