Electrical basics

[JamesCH95]

Originally Posted by SteveGarward

Final soldered connections for the competition robot are often checked by a mentor, and usually at the request of the student. It's not a lack of trust (on our part) or confidence (on theirs), but a matter of quality assurance by all to ensure we are building the best that we can.

In any case, I would want to be able to say we did everything we could to ensure a good mechanical connection.

What we (on 95) have done to ensure a good mechanical connection is to adjust our ratcheting crimping tools and then test the crimp connections that they make. We get awfully close to mil-spec pullout strengths with these connections (around to 130lbs on 10awg connectors, almost 300lbs on 6awg connectors) and dissecting these connections shows nearly continuous metal through the crimped cross-section due to deformation and micro-welding. This qualifies as a "good mechanical connection" in my book at least! Two robots and counting on this process (plus pre-season drives and other projects) with zero failures. The two robots before that used soldered connections, also with no failures.

Soldering relieves all of the cold-working from crimping making the crimping process pointless. Most solders only begin to melt at around 200C (depends on formulation), and copper will start to stress relieve around 150-200C (depends on alloy).

I'm not saying that soldering can't work, or doesn't work; my team and I have used numerous soldered connections with great success. Both soldering and crimping are perfectly valid methods of joining connectors to wires. What I am saying is that it is pointless to do BOTH to the same terminal. It is simply a waste of time because soldering essentially undoes crimping.