praise dakinis

I'm wanting to hook up my Shimano UR-700 hub dynamo to a Busch & Muller Luxos U in the front and B&M Toplight Stand Light in the back. The doubt wire that came with the Luxos is fine, but not long enough for both. I wonder if I can do coaxial cable from the Home Depot with some female insulated disconnect ends with heat shrink tubing. SON also does coaxial cable but I'd like to take a trip before I might be able to get any. Anything wrong with doing Home Depot coaxial? Or does anyone have any other recommendations that's worked well for you? (Exquisite detail and photos welcome!)

unterhausen

Moved this from General to Electronics

I usually use B&M wire, which is like speaker wire just smaller gauge. Home depot says they have 24gauge, but you have to order it. Might as well get the B&M wire.

I'm surprised you didn't get any with the taillight.

If you mean RG59 when you say "coax," I don't see how that's going to work.

base2 

I wouldn't bother with coaxial cable. So much of it is garbage with aluminum stranded shielding around a solid conductor...It's thick, bulky, inflexible & guarenteed to break, suffer water infiltration. There are better coaxial cables, of all size & capabilities of course. But they cost a lot more than the Home Depot has. (One example. Copper, stranded, thin, flexible.)

Why not just go to the Goodwill & buy a wall wart with stranded copper twinlead for a dollar at the consumer electronics pile?

Cut the cord off the wall wart & install spade terminals. The male end is on the light, the female gets crimped &/or soldered to the twinlead zipcord.

Tourist in MSN

I am also surprised you did not get enough wire.

I am not familiar with the coax or home despot wire you are proposing.

And I have no clue what a wall wart that was proposed by Base2 is.

On my bikes I bought some single conductor, multistrand wire at the hardware store, not sure the gauge but am guessing it was about 22 gauge. Twisted two pieces together and zip tied that to the fork after putting the dynohub connector on one end and a pair of 2.8mm spade female connectors on the other end. See photo.



The above photo before I added a taillight, thus only two wires plugged into the Luxos U.

The reason that I wired it that way is that for several years I had one dynohub wheel and used that wheel on three different forks, thus that was how I wired my forks on several bikes. Now that I have more dynohubs, I am still wiring them the same way since it seemed to work well. And the wire I used is more robust, unlikely to break if it is snagged on something.

Later I added a taillight. I chose not to use the B&M wire, because I did not have enough. I used the same wire from the light to the bottom bracket area as I used on the fork, zip tied that under the downtube, at the bottom bracket area I used 2.8mm spade connectors to connect to different wires that I had glued inside my fender. That wire was glued inside the fender from the bottom bracket area to the taillight that was bolted to the fender. Used a quick connector at the fender in case I needed to remove the fender or in case I had a problem with my glue job. Photo below is after I added that taillight and the wiring for it.



The mount on my light is one that I bent up myself, not an off the shelf B&M mount. So, do not try to find it in the B&M catalog.

Side note: If you do not have a long enough bolt to run through your fork crown for the light bracket, I used several nuts and a piece of threaded rod.

You should be aware that the four spade connectors on the back of the light are not well weather sealed. If you ride without a fender, tire spray could cause a water ingress problem with the light.

My wiring jobs generally are not as nice looking as some done by others, so look at some other bikes if you have a chance, you might get some good ideas from others.

For a possible wire source, I have had some calculators and other devices that had a small step-down transformer plugged into an outlet that had a long two conductor black wire to the calculator or other device. Some of those I clipped the wire off of them before I discarded them to save the wire for a future wiring job. Such step down transformers might be a source for some wire similar to the B&M wiring that you lack.

I am using SP or Shimano hubs, I can't comment on the best way to connect the wires to a Son hub.

I think you will like the light pattern from your light. But be forewarned that some have had water ingress problems with that light. I have not had water problems with mine but I am careful to avoid heavy downpours and when I have had the bike on a rack on the back of my truck in rain, I put a plastic bag over the light. And on the bike, it is under a handlebar bag.

Good luck with your wiring job.

praise dakinis

Thanks for this awesome post! Your light looks great there, and gives me some ideas. I've got mine on the front right of a Nitto M18 rack, and the rear Toplight is on the back of a Tubus Logo Evo knockoff (waiting for them to come back in stock!). I like the c***** wires you're running, wound together -- that looks like a good stout solution. I wonder if it would work to run them gently around the rear brake cable from the front to rear light? If it wouldn't affect the braking power? For water ingress it makes me think to maybe cover the connections up with some self-amalgamating tape and maybe a little electrical tape over the top. I am hoping to be able to use it in all conditions on tour.
One other question for you: If you use the little cap that comes on the shimano dynohub, do you poke holes big enough to run the wire housing inside, or just the copper wire? I've heard that water ingress there can also be an issue.
Thanks again!

praise dakinis

Good to know, I'm new to coaxial cable. Peter White gives what seem like good instructions on how to set up SON's lighting coax cable here: https://www.peterwhitecycles.com/co-ax.php

Tourist in MSN

Wrapping a wire around a brake cable outer housing would not be a problem, I have done that. And I have done that over inner cable between cable stops too. I do not have any bikes with hydraulic brakes, I have no opinion on a wire around that hose. When you wrap wire around a brake cable, it is quite noticeable. And the thicker the wire is, the more noticeable it is. So, if looks is an issue to you, go for some pretty thin wire. I have dynohubs on several bikes but this is the only bike where i have a permanent taillight installed. The other bikes, the taillight is more temporary, as I might want to add a rack or remove a rack. And one of my bikes has S&S couplers, that is a major hassle to disassemble and pack and then reassemble, so when touring on that bike I only use battery taillights. I am thinking of gluing the wire into a rear fender on one more bike, so I might have perminent wiring on one more in a few months.

I did not bother to ream out the holes to fit the connector cap over the wire insulation. I have some Shimano hubs and some SP. Their little wire connectors are interchangeable, the photo has a Shimano connector on an SP hub. The bike in the photos in my previous post, this is the same bike. The photo is likely a bit confusing because I have a Tubus Tara front rack on the fork.



So, if I have this correct, you have a Shimano hub, a Luxos U, and a B&M taillight that is mounted on a rack. Shimano hub is grounded to the fork, the Luxos U is not, and if my memory is correct the taillight is not grounded to the frame. So, everything should work fine.

***

If you are using a Luxos U to charge up a phone or GPS while touring, if the power out of the USB charger cable becomes intermittent, that is normal. There is a small pass through cache battery in the light. If you are running power to a device (phone, GPS, powerbank, anything) and that device is taking power faster than the hub will produce it, then the internal battery gets depleted. When that happens after several minutes of the USB charging being shut off, the internal battery has some charge again and then the USB power will start flowing for a while. When that happens, I just unplug whatever I am charging for half an hour or more to give it time to charge up the internal battery.

If the lights are on, very little power comes out of the USB port, so if you are trying to charge a phone while your lights are on, your phone will not get much of a charge. The lights will consume most of the power.

On a couple of occasions my Luxos U has turned on by itself, I only learned that later and in the process learned that I was not getting much power out of the USB port for that time.

Almost all of my touring, I leave the dyno powered lights off, if I have them on the bike. But usually have a flashing battery powered taillight turned on when touring.

base2 

I didn't know Peter White sells the coaxial cable. Yep, he's got some of the better stuff. (copper with copper all stranded) I disagree where he says not to solder. I prefer more than a simple crimp for mechanical robustness, but there is nothing wrong with his way.

Where soldering tends to go wrong is when an amateur attemps to solder, & for whatever reason solder starts wicking down the strands making for a solid conductor. A solid conductor tends to break. Another common mistake is to use acid-core solder. Acid-core will eat the connection until there is no wire or terminal left.

Given the number of possible mistakes customers can make, it's probably good business to recommend the crimp only approach.

It's a good thing you are not familiar with the offerings of Home Depot. Any offering they have for is unlikely to be suitable for this application. I only mention it because cable tv cable is most peoples association with the term "coax" & the OP is going to have a lot of dissapointment in his future if he starts his journey with cable tv wire or home improvement stores in mind.

Wall wart is a derogitory term for a plug mounted consumer appliance a/c adaptor. Wall wart was just easier to type.

But its me 

When I first installed an IQ-X Front and toplight rear I went with the provided B&M cord, using additional B&M connectors, and some heat shrink. Having a good Knipex crimper, wire stripper, and DeWalt heat gun helped, and I already had those tools from other projects. I ended up using small cable ties to secure the cord along the brake line to the rear. When I upgraded to an Edelux II, I went with the SON cord. I ordered it from Rivendell ($12), with both ends premade for B&M light connectors. Ended up replacing the connectors on one end with the SON connectors, but the Peter White cord can be made custom sized with the B&M connectors saving you the prep aggravation. It took me several tries at cutting the SON cord, as the outer copper was easily nicked by my clumsy hands (I’m a crap at soldering too). What I did that makes for a cleaner look and less chance of snagging the cord on anything (something I did with the B&M cord, losing my rear light power for several rides before realizing it), was to use heat shrink to attach the SON cord on the brake line. Pardon the filthy, winter long commute bike, but here is a shot of some of the cable routing:

unterhausen

There is very little benefit to the Schmidt coax cable that Peter White sells over the B&M wire. It's a little more compact, and it's prettier. If such a thing can be said about wire. The electronics industry as a whole doesn't use coax for applications like this. Stealing from a wall wart is a good idea, but it's not likely to be long enough to get to a taillight.