Four 14 gauge wires soldered to tinfoil is a recipe for disaster, this was a totally avoidable issue and the people who designed/made that connector should be held accountable and if I had my way punished by being lashed severely with a wet noodle of shame!
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The fact that there doesn't appear to be any mechanical strain relief either,
Four 14 gauge wires soldered to tinfoil is a recipe for disaster, this was a totally avoidable issue and the people who designed/made that connector should be held accountable and if I had my way punished by being lashed severely with a wet noodle of shame!
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Yeesh, from an electrical/mechanical engineering perspective that's a masterclass in how *not* to do it.
Solder is not glue, and a joint that will experience any mechanical stress, bending or vibration that is attached that way can be expected to fail.
I wouldn't be shocked if these progressively got worse as they age and are uninstalled/reinstalled, bent back and forth, etc. Lead-free solder (which this presumably is) only makes the situation worse, as it work hardens, fatigues and cracks with mechanical and thermal cycles.
For something like that you'd want to make a solid mechanical connection
first and then solder afterward. They make terminals/receptacles with proper 180 degree or 360 degree wrap around the wire so you get a lot more surface area for the solder and a much more reliable mechanical connection... but I don't know why they aren't used here.
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Choosing the right contacts is not always easy, especially if you do not have engineers specialized in interconnect designs. The quick answer to the
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When I'm making automotive/racing wiring harnesses, I always both crimp and solder for mostly the best of both worlds. You get the mechanical robustness and strain relief of the crimp connection, along with the hermetic seal, corrosion resistance, and lower overall series resistance of the solder.
For the same reasons, if you ever look at an OEM wire-to-battery-terminal connection on a car that carries hundreds of amps to the starter, it's almost certainly going to be crimped for the
mechanical reliability.