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Yesterday I went back to my office bike shelter to discover the light mounting tab is broken, so I can see very well what is lying on the right side of the road, but not the road itself. Luckily, a colleague offered me a spare 12-Volt Supernova light, that I can mount simply with a bolt through the bike light mounting tab.

Both I and my ebike are cheap ones, so I do not want to tore down the motor to check where I should connect the light, I just want to cut the cable of the old light and connect the new one.

However the black&red power cables residing inside the single cable are very thin, all the female/male connectors from my "dynamo-powered light parts" drawer are too bulky and the connection is diffcult and ugly. What kind of connectors are more convenient/enough for these lights?

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  • Consider asking this question on one of the electronic/electrical stackexchanges.
    – MaplePanda
    Commented May 10 at 14:45

1 Answer 1

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Since you won't be disconnecting and connecting the light often, but rather install it once and then use it for a number of years, I would actually suggest not a connector but rather a soldering iron and some lead-free solder. Then when you have soldered the wires, put some self-amalgamating tape (I use Nitto brand but there probably are other brands available) over it. The self-amalgamating tape is stretched and the act of stretching it and subsequently wrapping it over itself causes it to fuse to itself and create a permanent water-tight seal.

I guess an alternative would be some miniature spade connector, but good luck finding such a connector for the thin wires used in this application, and even better luck finding crimp pliers for such small connectors.

For thicker wire, 0.75 mm2 - 6 mm2, I use Anderson PowerPole if I need to disconnect and reconnect it often (these are so easy to disconnect that it can happen due to accident, so not recommended for permanent connections), and 6.35mm spade connectors if I want the disconnecting force to be greater (harder to disconnect intentionally, but harder to disconnect accidentally too). The female spade connectors are available either as insulated or as non-insulated open barrel crimps. The non-insulated open barrel ones require a different crimp plier but make a more durable crimp, the insulated ones make a worse crimp and require different crimp plier than open-barrel ones, but you save yourself the hassle of wrapping self-amalgamating tape over it.

But none of these are intended for such a thin wire as used in dynamos and e-bike lighting. Also, all of these are very bulky and look ugly if the wires are thin.

I guess one trick that might work is folding the end of the copper wire back at the end, so that you have two uninsulated wires next to each other. Then those two uninsulated wires can go to a crimp connector that's intended for 2x the wire area. That's what I sometimes use if the wire is much thinner than intended for the smallest Anderson PowerPole. But I won't recommend that here, since the connection would look bulky and ugly.

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  • Concur on the solder - there's water-resistance to consider here too, and any removable connector will be vulnerable to dirty water ingress.
    – Criggie
    Commented May 9 at 12:27
  • Spade connectors and similar crimping based solutions are inferior to soldering in terms of withstanding oxidation as well. At a minimum for crimp-based solutions, you must use gold-plated ones. But best to avoid altogether, since a bike is extremely exposed to moisture and damp air. The only down-side with soldering is that the joint will be somewhat vulnerable to mechanical strain, so some manner of strain relief is required to keep it out of harms way.
    – Lundin
    Commented May 31 at 14:17
  • Oh no, a properly executed crimp is airtight and won't oxidize. Far better than any solder can be. A bad crimp can be worse than solder, though. Source: en.wikipedia.org/wiki/Crimp_(joining) which says "A well-engineered and well-executed crimp is designed to be gas-tight, which prevents oxygen and moisture from reaching the metals (which are often different metals) and causing corrosion"
    – juhist
    Commented Jun 2 at 9:49

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