Author Topic: Wiring rear dynamo driven light  (Read 16164 times)

garyper

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Wiring rear dynamo driven light
« on: October 25, 2009, 11:37:56 AM »
Hi Everyone,

I've placed my order for two Raven Tours (the wife wanted one as well).  I have been running a Schmidt on my current steed and for the rear lights I simply ran twin core along the top tube held with cable ties but it always seems to look a bit unsightly.  Is there a nicer way of doing it, I want to minimise anything that could spoil the lines of our bikes ;)

Many thanks
Gary
Darwin, NT, Australia

Hbunnet

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Re: Wiring rear dynamo driven light
« Reply #1 on: October 25, 2009, 01:03:06 PM »
You could use co axial cable.
 

pastafarian

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Re: Wiring rear dynamo driven light
« Reply #2 on: October 25, 2009, 03:40:10 PM »
When you say "along the top tube", do you mean on top of it? Mine runs along and in between the other cables under the top tupe. I bundled them together with cable ties and it doesn't bother me aesthetically.

jawj

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Re: Wiring rear dynamo driven light
« Reply #3 on: October 25, 2009, 04:24:56 PM »
Short of using induction or microwave power transmitting I think the only way you're gonna manage to power your rear light from a front hub dynamo is with a cable...

Mine runs under the toptube alongside the brake hose and is fairly neat, but I'm not proud of how it's wound around the rack stay, then tranverses empty air to be wound around a bit more rack before finding the light: when I'm very bored one day I'll probably gaffer tape it (neatly) along the top of the rear mudguard.

Sheesh, why must we be such slaves to æsthetics??

stutho

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Re: Wiring rear dynamo driven light
« Reply #4 on: October 29, 2009, 10:30:14 AM »
or microwave power transmitting

... and use the frame tubes as a wave guide?  ;)

garyper

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Re: Wiring rear dynamo driven light
« Reply #5 on: October 30, 2009, 07:39:13 AM »
Thanks guys, I'll now put some thought to the wave guide idea.  I wonder what the resonant frequency of a Raven Tour top tube is?

Cheers
Gary

stutho

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Re: Wiring rear dynamo driven light
« Reply #6 on: October 30, 2009, 01:33:14 PM »
Quote
I wonder what the resonant frequency of a Raven Tour top tube is
lol ;D

I did once upon a time consider powering a rear light using the rear brake cable outer as the 'other' conductor - I used to be an Electronic Engineer so eccentricity like this when with the territory.  I never did try it though - too much chance of failure.

Andre Jute

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Re: Wiring rear dynamo driven light
« Reply #7 on: November 17, 2009, 05:56:27 AM »
Hi Everyone,

I've placed my order for two Raven Tours (the wife wanted one as well).  I have been running a Schmidt on my current steed and for the rear lights I simply ran twin core along the top tube held with cable ties but it always seems to look a bit unsightly.  Is there a nicer way of doing it, I want to minimise anything that could spoil the lines of our bikes ;)

Many thanks
Gary
Darwin, NT, Australia

A standard way of running the twincore to the rear light on bikes for the Euro elite is from the front lamp mounting around the head tube, down the underside of the bottom tube, under the bottom bracket shell, along the chainstay only as far as the mudguard brace, thence over the top of the mudguard to the lamp. If the cable isn't stiff enough to support itself between mudguard attachments where it will also be clipped, it can be covered in a sheath. I saw a kit for doing it but can't now find it. This is tidier than what you have only on the assumption that mudguard and the wire are the same colour and that you have a rack fitted. Some frames have holes drilled in the chainstay brace to pass the wires through. -- Hobbes (not currently in Adelaide, SA; wish I were though!)
« Last Edit: November 17, 2009, 06:02:21 AM by Hobbes »

strouf

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Re: Wiring rear dynamo driven light
« Reply #8 on: October 22, 2010, 07:24:48 PM »
I have the same "problem" with my sherpa... Do you think that drilling a 3mm. hole in the front end of the downtube would weaken the frame?

PH

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Re: Wiring rear dynamo driven light
« Reply #9 on: December 07, 2010, 10:07:50 PM »
Hi Everyone,

I've placed my order for two Raven Tours (the wife wanted one as well).  I have been running a Schmidt on my current steed and for the rear lights I simply ran twin core along the top tube held with cable ties but it always seems to look a bit unsightly.  Is there a nicer way of doing it, I want to minimise anything that could spoil the lines of our bikes ;)

Many thanks
Gary
Darwin, NT, Australia

On the Raven it will be a lot less noticable than on most bikes as you'll have three cable outers running the full length to run alongside. 

kwkirby01

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Re: Wiring rear dynamo driven light
« Reply #10 on: December 08, 2010, 10:51:35 AM »
I have the same "problem" with my sherpa... Do you think that drilling a 3mm. hole in the front end of the downtube would weaken the frame?
No idea about the hole weakening the frame. But on my Sherpa I do exactly as Hobbes described - along the down tube, underneath bottom bracket, then inside the mudguard. I drilled a small hole in the mudguard to exit the cable to the carrier mounted rear light. Works just fine and doesn't look too bad either. Kevin
Kevin K. Glasgow

il padrone

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Re: Wiring rear dynamo driven light
« Reply #11 on: February 04, 2011, 09:18:10 AM »
On my Thorn Raven Nomad that I've just completed building, I routed the cable in a similar fashion, using cable-ties to fasten it to the gear cable, but carried it right through along the chainstay and then cable-tied it to the rear strut of the Tubus Cargo rack and up to the Supernova E3 tail-light, mounted on the rear of the rack. Works very nicely, almost invisible to an uninformed observer  8)

Cheers Pete

(also in Australia, but Melbourne, Victoria)
« Last Edit: February 04, 2011, 09:20:20 AM by il padrone »

Danneaux

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Re: Wiring rear dynamo driven light
« Reply #12 on: July 27, 2011, 04:50:20 PM »
In the early 1980s, I took a different approach when a bicycle I owned sported ESGE Chromoplast fenders.  Thinking the foil layer between the clear plastic laminations should conduct electricity, I used a Dremel Moto-Tool and the end of a spiral cutter to carefully remove the top layer of plastic, exposing the foil in spots at either end of the fender.  I then drilled a small hole in the crater and passed a stainless steel bolt, flat washer, and nylock nut through the holes, tightening the assembly into a terminal.  I then covered the edge interface at the washer with a thin layer of beta-cyanoacrylate gel to make it watertight.  Power connections were made with eyelet terminals at either end of the fender using thin stainless flat washers, split washers, and plain nuts, insulated with a small vinyl cap intended to plug an automotive vacuum line.  At some later point, ESGE marketed fenders with a snap-lead connection using the same conductive foil idea.  The foil inside was thicker and more robust than it appeared.  Though still relatively thin, it was wide enough to make a reasonable low-impedance taillight lead.

The taillight I used grounded to the rear rack which was itself grounded to the frame, so all I needed was one power lead.  The fender had three separate foil strips, with the fender stays grounded to the center foil strip, so it could have been used in the same way for a ground return.  It was a very neat looking setup and extremely reliable.

I commuted with this setup for many years, riding and parking in extremely wet Oregon (USA) weather and never once had a failure using this taillight wiring with a number of generators from that era -- Union 9817, Union BB roller, and Sanyo DynaPower BB roller.  The setup was still working when I changed to a wider fender and LED blinky taillight.

As for drilling a frame to route wires internally, I have done it successfully, but only on lugged frames, where the hole was very small and drilled through the center of the underside tang for the headtube-downtube lug and exiting the center-bottom of the BB, generally using a line-bored bolt to replace the one already securing the BB underside derailleur cable guides.  It is as simple to continue the lead through the left chainstay to the rack strut mounting.  I am a hobbyist framebuilder and have never had problems doing this on my own and commercially-produced frames and no sign of cracks have appeared to date (>35,000 miles of hard touring use on each of the frames).  However, on a fillet-brazed or TiG-welded frame, I would have reservations.  While the area in question would be butted, without a lug there is a chance for crack propagation away from the drilled hole.  I wouldn't try it and I would imagine it voiding a frame warranty.  The way to do it "properly" on such frame would be to braze small piece of brass tubing into the hole, much as the Taylor Brothers did on one period frame I've seen.  The little piece of tubing extends slightly beyond the hole on either side, serving as a reinforcing lug on, say, a fillet-brazed frame.  I've done that successfully on one of my frames, a folder.  It is also possible to route wires through existing frame vent holes, leftover from the building process.  Some frames already have holes of sufficient size, usually in the stays, and some have to be enlarged or ovalized very slightly.  A vacuum cleaner is used to draw sewing threads through the holes and that is tied to a fine piece of florist's wire that in turn is soldered to the end of the electrical lead so it can be fished through.  This method can often be used nondestructively on a built frame to route the leads from the BB to the base of the rack strut.

I'm in-process ordering a Sherpa in satin black, and plan to use a combination of zip ties and black automotive trim tape to conceal/route the wire.  The trim tape I'll be using is also satin finished, has a very stable low-creep adhesive, and is intended to overlay and replace the finish on black-colored, metal automotive window trim.  The brand I'll be using is by Trim-brite; I've had superb luck using it in the past to protect my black powdercoated carriers from pannier hook abrasion.

Hope this helps,

Dan.
Eugene, OR -- USA
« Last Edit: October 27, 2013, 07:32:17 AM by Danneaux »

Danneaux

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Re: Wiring rear dynamo driven light
« Reply #13 on: October 19, 2011, 03:09:33 AM »
For those who have written me to ask...

As a follow-on to my previous post, here is what the fender-foil electrical terminal looks like on an ESGE/SKS fender.  The head of the machine screw (inside the fender) contacts the foil at the core of the fender, while a washer and nylock nut complete the terminal on the outside.  Another washer and a second nylock nut capture the electrical lead on the outside (usually a soldered "eyelet" connector).  The base of the terminal is weather-sealed with a gel beta-cyanoacrylate.  All hardware is stainless, 3mm.  The rear fender pictured has one terminal located down by the bottom bracket and the other near the upper-rear of the rack, so it can supply the taillight.

 I used the grounded rack as the return path for the generator current, but but it would be as easy to create a second terminal on one of the other foil leads on the fender; there are three.  Two are discrete, while the middle track is often conductive to the fender brackets from the factory and thus to ground, via the fender stays.  If the bicycle itself has chromed stays/fender mounts or cleanly-tapped bosses, then the fender stays will form the ground-return path if there is a terminal at the other end.  It is also possible to run two separate hot leads on these fenders with a common ground, using diodes to direct the current.

This setup never failed me in many years of wet-weather commuting and touring. It gives a very clean, nearly wire-free look, and allows the fender to be demounted for shipping or maintenance.

[Edit:  For instructions and illustrations of another way to do it, see my post at: http://thorncyclesforum.co.uk/index.php?topic=3896.msg17113#msg17113 ]

Best,

Dan.
« Last Edit: January 12, 2016, 03:36:14 AM by Danneaux »