Encoder Wires

Is it better to crimp pwm cables to the encoder wires or solder them?

I would solder them…
We just cut an extra PWM cable and soldered to the KOP encoder wires to the correct wires.

You don’t really crimp a wire to another wire.

We crimp PWM pins onto the encoder wires, slide on a 1x5 housing (so if we ever want to use Jaguar closed-loop feedback we don’t need to modify anything) and use a custom-made splitter cable to bring the signal to the DS. All the supplies and tools we use for this process come from Hansen Hobbies. It takes a bit of practice to crimp the wires properly, but it’s well worth it when you finally do get the trick down. I personally prefer it because it keeps the wires clean.

Soldering is a quicker and simpler process, but take care to ensure that you don’t damage the encoder wires whilst doing so; also remember to properly insulate the connection.

Soldering is easier and will also last longer. Just make sure to have either heat shrink or electrical tape for the solder afterwards.

Our Team usually uses Pwm crimping because we can then plug the encoders in to Jaguars or the digital side car. We just bought a hobby kit with a bunch of connectors and pins, which was relatively cheap (24 dollars for all of it). Pwm is easier than soldering because of the time and skill required to make each one.

I agree, except no electrical tape for me. Its heat shrink all the way for any cable going on the actual robot. Custom PWM cables can be nice and convenient but most teams do not have the proper tools and supplies to build them. Also, this is usually not very high on their priority list because there are reasonable work arounds and there are usually many more supplies and tools on the list that the average team will want to invest in before this.

I don’t think you can ever completely avoid the need for soldering cables, and a properly done job is not inferior to fully custom cables. There seems to be an almost unlimited number of unusual connectors used in a FIRST robot and you never seem to have all the right parts to build at least some of them. However, very good results can be obtained on almost any of these connectors by simply developing good soldering skills.

Make sure you have a good soldering station set up with the correct tools. A good soldering iron with a water bottle for the sponge, a few sizes of solder, hand tools, proper lighting, and magnification. I keep a headband magnifier at ours. You will also need several sizes of heat shrink tubing handy. And a heat gun! Don’t let students use a soldering iron, lighter, or other inappropriate source of heat for heat shrink. I would rather use an old hair drier than any of those.

Our team had no soldering station last year and no training in soldering. Soldering was also a job no one wanted to do and their work showed it. This year they have a reasonable station with more supplies and better training. Several members of the electrical team now want to show off their skills and will ask, do you want anything soldered? The quality and reliability of the cables the students produce is like night and day.

Butt connectors are really easy to crimp and use, but in this case, because you are dealing with connecting different wire gauges, soldering is definitely better.

Solder them, one less thing to worry about when trouble-shooting.

Soldering is not always the best way to go. In this case the encoder wire insulation will melt back quickly if you are not careful. Crimping is very reliable if done properly. We crimp the encoder wires to a socket pin, insert them into a 6-pin version of the PWM connector then run 2 regular 3-pin PWM cables back to the sidecar. This way you can remove/replace the encoder and/or transmission more easily in the pits (and in a hurry).


Well you could always do both. crimp the connectors and solder the connectors. It ends up taking a while and is still probably not worth the time and effort for most teams, but it works well when done very carefully.

Soldering connectors, as Keith pointed out, is an especially unappealing option in this case. Given that the encoder wires are 28AWG, it’s very, very easy to accidentally melt the wires back. What’s more, plying a properly crimped connection with solder makes it brittle and actually weakens it.

Put the heat shrink tubing onto one of the wires before soldering. In fact, you might try five tubes in all. One for each of the joints, and one larger one to go over them all. I concur about not using flames to shrink. If allowing a teen to shrink, threaten punishment in advance for aiming the heater inappropriately. ::safety:: Hair dryers are weak (diffuse) compared to the concentrated stream of the tool for shrinking.