Schmidt/Lumotec wiring instructions

The SON (Schmidt's Original Nabendynamo) axle has two male spade connectors. In the photo below you can see one female wire connector attached to a male axle connector, and the other connector pair unattached.

The hub must be aligned in the fork so that those connectors are on the right (chain) side of the bike. If you have an older hub with a black painted center section, it makes no difference which way you align the hub in the fork. The Lumotec and Lumotec Oval Plus headlights come two ways; a 50cm wire with female spade connectors attached, and with an extra long 100cm wire with bare wire ends and loose female spade connectors. The Schmidt E6 is also available with two wire lengths; 50cm with connectors attached, and 120cm with loose connectors. The long wire versions can be cut to the length you want. Instructions are included for attaching the loose female connectors to the wire after cutting the wire to the appropriate length for your particular installation. Always leave yourself a few extra inches of wire that you roll up. You never know if the wire might be damaged and you might have to splice it back together. Having a bit extra never hurts.

For a single headlight installation, the wiring is quite simple. Even I can get it right! The two female spade connectors are slid onto the two male connectors on the SON axle. It makes no difference which wire connector goes on which axle connector, as the hub is not grounded to the frame. See the photo above. By the way, Shimano dynohubs, and all others made by Sanyo do ground to the frame via the axle.

If you are using a dual headlight, in other words, if you ordered a Secondary Lumotec, or Secondary E6-Z, things get a bit more confusing. The Secondary headlights look exactly like a plain old garden variety Lumotec or E6, except that they come pre-wired with an 80cm wire instead of 50cm, and one of the two female connectors has a male plug soldered into it. In the photo below, the upper connector has a male plug installed.

The male end is used to connect to one of the female connectors on your Primary headlight. The other female connector on the Primary, and the female connector on the Secondary can now be attached to the two male connectors on the SON axle.

What you're seeing in the photo above is two wire pairs; one each from a Primary Lumotec and a Secondary Lumotec. The Primary has two female connectors; the Secondary has one female and one male. One female connector from each light is connected to the hub. The other two connectors; one female from the Primary, and one male from the Secondary , are connected to each other. As you can see, this results in the lights being wired "in series".

If your primary headlight is the Lumotec Oval Plus, you must isolate the secondary light from any ground connection with the Oval Plus. So, let's say the Oval Plus is your primary, and it is mounted on a metal bracket at the fork crown. Perhaps you have Low Rider braze-ons on your steel fork, and you would like to mount a Secondary Lumotec directly to one of those braze-ons. This won't work, because both headlights will be making a ground connection to the fork through their mounting holes. A better solution is to mount one or the other headlight with my nylon handlebar mount to your handlebar or to an Excess Access bar. That will isolate that headlight's ground connection, preventing interference with the other headlight. This is only an issue with the Lumotec Oval Plus.

So what do the switches do?

The switch on the Primary Lumotec or E6 will turn both lights "on" or "off", if the switch on the Secondary is turned "on".

The switch on the Primary Lumotec or E6 will turn just the Primary "on" or "off", if the switch on the Secondary is turned "off".

The switch on the Secondary Lumotec or E6 will turn the Secondary "on" or "off" if the switch on the Primary is turned "on".

The switch on the Secondary E6 or Lumotec will do nothing at all if the switch on the Primary is turned "off".

Connecting a rear light.

The rear light attaches to the primary headlight in a single or dual headlight setup, not to the Schmidt hub. Only the headlight(s) are connected to the hub. The E6, Lumotec and Lumotec Oval Plus headlights have small spade connectors on the bottom.

They are marked for power and ground. If your frame is steel or aluminum, you can usually power the taillight with a single wire from the headlight to the taillight. This is because the ground connection can be made through the frame. When the headlight is attached to a steel bracket and mounted to the fork crown, a ground connection is automatically made to the fork.

There are some exceptions to this. Some headsets will not conduct electricity. The Shimano sealed cartridge bearing headsets for instance, will not conduct. So if you have one, you will need to run a wire from the headlight's ground connection to either the main frame, or run a second ground wire from the headlight to the taillight, along with the power wire. In that case, I like to wind the two leads together for a cleaner installation. We have double strand wire with connectors at one end available for this purpose.

The nylon handlebar mounts also will not conduct electrical current. So if you use it and a taillight, you will need to run a second wire for ground.

This is the ground connector for the Schmidt E6 headlight. The flat part with the hole in it is placed against the aluminum base of the E6 headlight and the bolt that holds the headlight onto whatever mount you use will also hold the ground connector. By having the connector pressed against the base the connector gets the ground current from the base.

Here's the E6 headlight with the custom handlebar mount. You can see the ground connector between the base and the black mount. The right end of the connector has crimps that grab the wire and the wire's covering. You use pliers to bend the crimps onto the wire. You only use the ground connector if you are using a wired taillight in the system. The ground connector is not used to connect the Primary to the Secondary. That connection is entirely independant of the wiring to the taillight.

Here is the same E6 headlight and it has a power lead attached for a taillight. If you go back up a bit and look at the photo just above you'll see an opening for the power connector. Now in this photo the connector is attached to the taillight wire. And the ground connector is there for the ground wire.

Some of our taillights ship with a single strand wire. That's because traditionally the commuter bikes in Germany have been made with steel frames and with headsets that conduct electricity. So the ground connection has always been made from the fork where the headlight is normally mounted, through the headset and into the frame. Then it is passed through to the fender or rear rack to whichever is holding the taillight. So you have normally only had to run a single wire for power.

But the E6 headlight is too heavy for the metal fork crown mounts that are made for the Busch & Müller headlights. Se we mount the E6 with a nylon handlebar mount which doesn't conduct electricity. And many frames no longer conduct electricity through the fork and frame. Some headsets like the Shimano sealed versions like Ultegra don't conduct electricity. This means you'll need a second wire for making the ground connection.

We have a double wire with connectors attached at one end if you need it.

Single strand wire, 185cm, connector on one end: $ 1.50

Double strand wire, 185cm, connectors on one end: $ 3.50

This image shows a single strand. But we have it with two strands side by side like electrical cord, only much thinner. And one end will have connectors for the base of the lights. With the E6 you would cut off one of the connector ends and use the ground connectior that comes with the E6 instead. The bare ends then attach to the taillight directly.

Schmidt Coaxial Wiring

It's more expensive, but Wilfried Schmidt has made up some taillight wiring sets that are much more durable than these double strand wires. They use the same heavy coaxial wire as used for their E6 headlight, and have a proper ground and power connector for the headlight end, and either 3mm female spade connectors or bare ends for the taillight end.

Finished with the 3mm taillight connectors, the price is $12, with bare ends and loose connectors, the price is $10. If you need to watch your pennies, by all means use the double or single strand wire above. But for the most durable connection, and even a better looking job, use the Schmidt Coaxial taillight wires.

I also stock Schmidt's coaxial wire by the foot. $.80 per foot.

Our taillights have connectors which are clearly marked for power and ground. Attach the power connector on the taillight to the power connector on the headlight, and do the same with the ground connections if needed.

Shimano dynohubs are diffent from Schmidt in that they do make a ground connection to the frame. That doesn't mean that the connection will make it past the headset to your taillight, but in most cases it will. If it does you will only need a single wire runing to the taillight if the headlight is also grounded to the frame. But you must be careful not to create a short. Any of the taillights that attach to a rear rack will ground to the rack. If by accident you attach a power lead from the headlight to the ground connector on the rack and if the headlight or Shimano hub is grounded, you'll create a short. The power leads must only be connected to other power leads whether at the Shimano hub or the headlight or the taillight.

I frequently get phone calls or email from people who want to try a different way of connecting their lights, often through the use of their own switch box, and they want my advice. Others want to use the output of the Schmidt hub for recharging the batteries of cell phones, Palm computers, hair dryers or Uranium PU36 Explosive Space Modulators. While I like Uranium PU36 Explosive Space Modulators as much as the next guy, I have no advice to give regarding powering one from the Schmidt. I only support using the Schmidt hub with the lights I sell and with the wiring pattern I recommend. If you would like to try something different, be my guest, but you're on your own.

To see how to mount headlights and taillights, go to the mounting lights page.

Back to Schmidt hub page

Back to Lighting Systems page

Back to: Products page

Back to: Peter White Cycles home page

Mail to:

The email link above uses javascript to hide the actual address from spambots. Your browser needs to be set to run javascript in order for you to use any of the email links on my website. If you can't see the links, you can call us or send a fax. You can also type the address into your email software. First, type the alias, "pjw". Then type the "@" sign. It's above the number 2 on your keyboard. Then type the domain, "peterwhitecycles.com". Don't put in the quotes! That should do it.

We use the javascript so that the spammers can't see the actual email address. I hope it works.

Sometimes the volume of email is so great we can't get to it all. For important communication, please phone, or phax.

It's best to call before 4PM Eastern time since after that we're either running around like headless chickens or at home ready to jump into the pot.

Under no circumstances should you place an order without first reading this.

This page updated: Wednesday, November 7, 2007

Peter White Cycles
24 Hall Rd.
Hillsborough, NH 03244
USA
603 478 0900 Phone
603 478 0902 Phax