Splicing wires

[evdog]

Can any of you electro-dentists help out an electronics newb?

Installing a new dynamo headlight on my bike, the wire running out of the light head has to be spliced onto an existing wire that runs to the hub. I want to solder it to ensure a solid connection.

Below is what I have to splice together. Been many years since I've done this. The wire isn't two strands you can easily peel apart - if it was I'd stagger the cuts of each strand. Instead, the unsheathed wire is runs between the white wire and the black outer insulation.

I'm planning on removing a bit more black outer, then maybe 1/2" of white on each wire. Slip two pieces of heatshrink tubing over one side - one short, one longer. Solder the white wire, shrink wrap it so it overlaps the white insulation. Solder the unsheathed wires. Then slip the longer heat shrink over the whole exposed wire so it overlaps black outer on each end. Shrink it. Done.

Does that sound roughly how it should work or anyone have better ideas. I've done a few test runs using similar older wire and it hasn't gone that smoothly. There are probably connectors I could run both sides into and then crimp. Do that and then solder, and shrink wrap?

[jacob_dbu]

You have a couple options, some cheaper than others and depending on looks as well.

1. Just solder, make sure you fold the ends over so it's like interlocking fingers, then do the heatshrink thing you were talking about over one wire first than the other. That should be pretty damn good overall.

2. This is the way that professional racecar teams do it. It's basically a crimper on both sides with a heat shrink tube over it and glue that melts at the ends. Super super slick, but kind of expensive.

See: https://www.digikey.com/products/en/...=0&pageSize=25

Pick your poison on which one to go with. I assume it's like 20-22ga wire. I'd suggest 967398-000-ND or if you want to go pricey (this is what my Formula SAE team used) than go with A101227-ND. Techincally there are "special crimp tools" for these, but you should be able to do it with a $10 crimper off Amazon.

There's also what is called Solder Seal or something like that here: https://www.amazon.com/Wirefy-Solder...ds=solder+seal

These are effectively the same as above, but they actually solder the wire instead of crimping. They still heat shrink and have glue on the ends. These are considered inferior in the racecar domain because a solder joint is brittle and prone to breakage under intense vibrations. Probably not an issue for ya.

Hope that helps!

[ShoNuff]

^^^^Spot on. Rosin core solder. Don't forget to slide the heat shrink on before you solder.

[billyk]

The rule I was taught was if you solder, make a good mechanical connection first with the wires. Don’t depend on the solder to hold the wires together. But crimping connections seem to work just fine.

[Supermoon]

A good solder connection will be the most streamlined and permanent solution. Do you need to disconnect the wires ever? If so, look at getting some bullet connectors. I got a bag of about 100 for 10 bucks when I was rewiring a motorcycle last winter. They will be fairly small compared to bigger connections but would allow you to connect and disconnect down the line. You crimp on to the end of the wire, then cover with heat shrink.

[GeezerSteve]

Nice dyno headlamp. Are you mating that to a Shutter Precision hub?

I've used butt crimps only and crimps/solder, covered with shrink wrap, for SP hub/light wire connections. Both worked and have held up fine.

[MagnificentUnicorn]

I'd use the butt crimps with the heat shrink coatings and then heat shrink over the whole splice. Done right a crimp is every good or better than a soldered splice.

If you want to be able to separate the hub from the light get some kind of weatherproof connector than you crimp on the wires.

[GeezerSteve]

FWIW, the Supernova E3 Pro2 headlight came with very nice mini butt crimps and weatherproof connectors, which I used without soldering and they have held up fine on my wife's bike for thousands of miles and lots of use.

[stuckathuntermtn]

I'd use the butt crimps with the heat shrink coatings and then heat shrink over the whole splice. Done right a crimp is every good or better than a soldered splice.

If you want to be able to separate the hub from the light get some kind of weatherproof connector than you crimp on the wires.

this. Butt connectors are the easy solutions. They're cheap and they work. Wrap completely in heat shrink or black tape to secure everything. They sell them everywhere and all you need are pliers.

[2FUNKY]

this. Butt connectors are the easy solutions. They're cheap and they work. Wrap completely in heat shrink or black tape to secure everything. They sell them everywhere and all you need are pliers.

Marine grade that are heat shrinkable. No other bullshit necessary.

[Jimi_Lee]

A couple notes which people missed.

Prep your wires before soldering together. That includes twisting them and then tinning the ends (melting some solder on to the ends, *sorry, don't know your background knowledge).

Crimps, especially with fine gage wires, can come off or break. I tend to solder the wire into the crimp. If the crimp comes with plastic covers, those can be pushed back and then put back on.

2Funky will not have to have crimps at this junction though. There will be crimps at the connection @ the hub ~18" away. Sure, adding crimps here would make it easier to take the light on and off the bike without having to detach that wire from the fork, but not sure how often or why you would do that.

[Timberridge]

You're gonna electrocute yourself, only a certified bike technician should be doing this.

[ghosthop]

Plenty of good suggestions in here, although for such a simple job I think much of this is overkill. If you do go with the butt crimps I would make sure to stagger the connections so they're not overlapping for a cleaner look. While a crimp is essential for heavy gauge wires in an application where there's vibration, e.g. connection from battery to starter in a vehicle, if you're confident with your soldering ability that's the way I would go.

If this were me, starting from your picture in the OP I would:
Strip the insulation from the two internal wires. Twist the ends together and solder.
Covered the exposed internal wires with electrical tape.
Twist the two ends of the exposed outer wire and solder.
Cover the whole mess with heat shrink.

I would still slightly stagger the two connections and make sure to use marine grade heat shrink with the internal glue that seals the ends from moisture when you heat it. The suggestion to tin the ends is also spot on, the way I was taught to solder wires is to heat the component itself (the twisted ends of the two wires in the case) with the iron so that the solder spreads evenly and throughout.

FWIW, flux will help, but you can still get leaded solder in Montana which is noticeably easier to work with and from the sounds of it will last you a long while.

Good luck, this is the sort of job you should finish before you finish your beer.

[stuckathuntermtn]

No point in soldering that. Also, I get to say butt connectors.

[jacob_dbu]

Hold them together as you ride!!! No need to waste time "setting stuff up"

[whyturn]

Solder should be nice and shiny not dull which is cold and will be brittle. Key is to tin wires first, let it flow and then meld them and move heat away. Also use good quality solder which will cost as much as crimping. So maybe just crimp it

[SB]

my wires are noises

https://www.facebook.com/45808400434...9370173219886/


You are supposed to hold one wire in each corner of your mouth, that way you complete the circuit and reap the benefits of electro shock therapy.

[Todd Zander]

just be careful when you turn it on as there will be major parasitic loss

[evdog]

Thanks for all the input! Got it done last night and it works.


After soldering and heat shrinking the first wire.




Second wire soldered. It looks ok, not great. I was expecting to have an issue with the second one because I'd need enough space between the two wires while soldering the second to not damage heat shrink on the first one. But at the same time keep it short enough to be able to sandwich them both into a second heatshrink tube. I put some folded tin foil between them to insulate the first wire while soldering. Had to scrunch them into the heatshrink, but they went.




Final product. Yeah, there is a weatherproof connector so I can pull the light off easily. There is another down by the hub so I can more easily disconnect the wire there too.




Mounted up next to the old light. Took it for a quick spin around the block and it works well. Will take it out next night or two and make sure I like the new one better.

[evdog]

Nice dyno headlamp. Are you mating that to a Shutter Precision hub?

Thanks! I've been using a Schmidt Son 28 with Edelux II for the last year or so. The Edelux was supposed to be one of the brightest lights at slower speeds but I didn't really like the light beam. It is better for road use. The beam is flat-ish on top so when leaning the bike in turns the beam angles too, if that makes sense.

The Sinewave has a rounder beam which will be better for off-road. It can be powered by portable battery and hub simultaneously which maintains brightness at slow speed. And it has a USB outlet right in the lighthead to charge devices instead of needing a separate charger/converter. Adding a pass-through portable charger I'll be able to trickle charge the charger at the same time it charges whatever device needs recharging.

Have some testing to do and make sure it all works well together.