I've been reading through this forum and lots of good information here, but I'm hoping to find a single how-to or FAQ that tells me in general terms how to wire a steel frame (or non-steel) bike for dynamo lighting and wired bike computer -- and at some point USB power for accessories. Just in general terms. I understand electricity and connectors but I don't know what the best practices are, routing, grounding, shielding, fastening, etc. I haven't had luck using the site search function so it wouldn't surprise me if I just missed the thing I'm looking for. Or maybe the best things to use are common sense and tape? Thanks for any help!
tape or wire ties. I have used both with success
There really isn't a tutorial that I'm aware of, either. Just kind of look for individual solutions for each problem you're having as you go along. And post lots of questions and pictures here!
I recommend using two strand wires of some sort. Trying to use the frame as a ground can present some challenges.
Having said that, the voltage, current and frequency involved are quite low and present little to no risk if something goes wrong.
Dang, my language, shielding and grounding! Sadly there ain't much of that stuff here. Not that many engineers really understand that stuff.
Originally Posted by mgb
Most routing is to minimize length of wire and to put the wire under the frame tubes. Two approaches to grounding: ground it all to the frame, or wired returns. On modern lights like a B&M Luxos, run all the returns to the headlight, not the generator, but it has a switch built in. I haven't seen anyone do muck with shielding that makes any clear electromagnetic sense, thought there are a lot of EMC issues between HRMs, boost or SEPIC-controlled LED lights, or computers.
Tape has to be handled carefully on a bike, since the paint is not always real sturdy, and the tape itself needs to be invisible. Another site has just had an article about Racer's Tape, made for auto racing. I'm thinking of routing my compute wires so they are as straight as possible and as close to the frame tubes as possible. I want to try a minimum characteristic impedance arrangement, uniformly secured to the frame with tape. It should isolate cable-borne noise from coupling between circuits.
No, there are no wiring guides as far as I know.
There are two basic ways: internally and externally. For internal wiring, you would need to have a fork that can accept the wiring through the drain holes and a frame that has the proper reinforced drillings.
I have two bikes that are wired externally. I use zip ties and black plastic twist ties. Around the headset area, I will cover the zip ties with electrical heat shrink to prevent the zip ties from cutting into the connectors. I wind the electrical lines around the right fork blade and hold them in place with zip ties. At the headset, I move the wire to the brake housing and wind around the housing. At the stem, I move the cable from the front brake line to the rear brake line, winding around and using black plastic twist ties.
The reason I use twist ties is that I want to be able to remove or change the wiring if I have problems on the road or if I ship the bike.
I can post pictures later.
I'd be happy to see pictures of a clean installation. What I have right now is a Sanyo bottom bracket dynamo that I'm going to eventually replace with something more modern. For wiring I'm thinking 22 gauge stranded. I don't think I should go smaller than 26 gauge or does that work in practice? The headlight/taillight set that comes with it is single wire, frame ground.
This site: www.reflectalite.com has halogen and LED replacement bulbs that should be brighter. These would be 0.4A for the headlight and 0.1 A for the taillight. They also recommend a dynamo regulator.
I want an installation that's well protected, not obtrusive, and semi-permanent, with connectors at the lights and at the generator so components can be removed individually. It looks right now like all wiring will be external.
A regulator is probably a good idea to limit overvoltage that might kill the bulbs. I know this is a significant issue with hub dynos and halogen bulbs, and logically it should be a consideration for bottle or BB dynos, too. Maybe the reg is just a voltage limiter, perhaps a zener in parallel with the filter capacitor. A buck or buck-boost converter would be very effective, but at the price of cost, packaging, and just more to worry about. I'm pretty sure an LED functions as a zener, but there's a question regarding whether the light LED can take the current surge in case an overvoltage occurs. Maybe someone here knows, but I don't.
Do you have access to wire gauge sizing charts? Are you worried about how thick the copper needs to be to minimize voltage drop? Check out the wire tables and application information at http://www.powerstream.com/Wire_Size.htm. From my time as a power electronics engineer, I think this is good information. These current and voltage levels are all too low for any of the National Electrical Code to be useful - it's all about preventing fires in houses and other buildings and industrial equipment.
Let's look at what's the smallest wire you can get away with. For a taillight, I'd figure a maximum loop length of 3 meters to a BB dyno, and probably about the same for the headlamp. At 6.3 volts nominal I'd not want to lose more than 0.25 volts in either loop. For the taillight the loop resistance should not be higher than 0.25V/0.1A = 2.5 ohms wire resistance. For the headlight wire loop it would be 1/4 of that, for 0.625 ohms. The wire resistance criteria then are 0.83 ohms per meter for the tail, and 0.21 ohms per meter for the head. Going now to the Powerstream chart, the wire gauges are AWG 28 gauge minimum for the headlight and AWG 34 for the taillight. Any wire gauges that are numerically lower (lower AWG number is bigger wire) are acceptable from a voltage drop point of view.
These are very thin wires, however, that might not withstand the handling and vibration of the bike, or perhaps even of installation. Some organizations, such as NASA and the Air Force, require no cabling wires smaller than AWG 24. I would agree with that, so I think your initial choice of AWG 22 for both the tail and head circuits is a very good choice. You should be able to build a mechanically strong and electrically efficient cable with that.
Thanks for the question, I've wanted to figure this out myself for my installation.
You can go thinner than 22, and it might work out, but it will depend on whether and how well you protect the cable against pulling on its solder joints or crimps, if it wiggles due to road vibration, or otherwise is stressed. If you can engineer the installation for stability of the crimps and joints against vibration and resulting fatigue, you can go smaller. But if not, you shouldn't go smaller.
The smallest connectors I was able to find at my local Ace hardware were labelled as 16-22 AWG. The wiring that came with my B&M lights was 24 AWG. The connectors are quite different, though, in the 24 AWG size.
Can you elaborate? For spade-type connectors, there are two specs: what wire size it can accept, and the width of the spade. The B&Ms use a really small spade size, and I'm not really sure of the wire spec for it. SON hub dynos use a little bit wider spade. Hardware stores usually sell what the handyman or home auto repair person needs, nowhere near the full (and huge) panoply of connection terminals for electronics. So far the only place where I've seen it reasonably easy to buy contacts the right size for B&M is Peter White's.
Originally Posted by DiegoFrogs
The ones I bought at my hardware store are the type that crimp simply by flattening a metallic cylinder on the conductor. The B&M type have those two sets of prongs that fold into a "B" shape, one of which grips the conductors, the other which grips the insulator. I screwed two of them up because I didn't have the proper tool for the B&M type and was hoping to buy a bunch of spares to keep on hand. I thought I'd be doing a bunch of modifications to make the routing more elegant and hidden, but I've been too happy riding to bother.
No doubt, in order to source them locally, I probably have the world's second best location with Peter's garage being the best. I really only looked at my neighborhood hardware store, though. I may try Radio Shack when I get back around to it.
Yes, I should have said that crimp area design is the third major specificaiton for a contact. Well, actually solderable (silvery) finish is right up there, too!
What store are you talking about, being the second-best location?
I checked our Radio Shack for small spades and for a crimper that looked right, with no luck. I bought an $8 crimper that did not work as needed. I ended up taking my trusty needlenose and gently bending the B&M ears down one at a time. I didn't get a B shape, but I did not damage anything. Then I soldered them as quickly as possible to minimize cold-solder issues. Then did the shrink tubes. I haven't tested anything in the rain yet, but it feels solid as I put it all together.
I've been looking for small spade connectors, too, and just today found some .110" male and female non-insulated connectors made by Philmore. They look like the right size to match the connectors in the Sanyo dynamo/light set. They're marked 22-18AWG.
I measured the proper B&M male spade and, indeed, it measures 0.110". The ones I bought were marked 0.167".
I pretty much did the same, but damaged a few while learning what to do and what not to do in the crimp. I didn't solder, though.
It's not the shop in particular, but the silicon valley tends to have stuff available that you might not find anywhere else.
Two electrical-work things I've learned the hard way:
1. Crimp-on connectors are not as easy to use as they might seem!
2. Put the bit of heat-shrink tube on the wire *before* you crimp (or solder, or whatever) the connector on the end!
Two thumbs up!
Originally Posted by sean999