We have had some issues with wires pulling out of the crimps using local hardware cheapies and are wondering if there are quality connectors and terminals that more experienced teams have had success with, please.
Since we started 2 years ago we’ve used XT-60’s off of amazon they provide easy disconnect for repair, troubleshooting, and working on things that need to change mid-competition. However, once they’re connected you’ll need to run a small zip tie through them to hold them together. I personally trust soldier and a zip tie more than any plastic clip.
Have you considered the quality of your final crimps or crimping tools?
Agreed. I personally recommend these or, as one of my maintenance buddies at work showed me, these. I used the former during my one year with 2783, for several personal projects on my truck, and for several large projects at work (industrial equipment modification). My co-worker has used the latter for over a decade’s worth of electrical repairs on equipment, with similarly good results (having tried it, it also is a good tool). Tip (works for me at least): don’t use the “insulated” part of the crimper. The “non-insulated” tooth will do a far better job of locking down your wiring.
As for the crimps themselves, my favorites have been Japanese crimps from work, especially the 2005 “PC-type” bullet pairs nichifu makes although last I checked they are available but a bit pricey in the US:
I work for a Japanese company with Japanese connections (no pun intended), so maybe we get a cheaper price. Or not. Either way, they’re the only bullet disconnect crimps I’ve ever had any luck with (from what I can tell we started using them in equipment around 2006 or so, 11 years of automotive part production is time tested enough? 
)
Otherwise, I prefer non-insulated crimps, with separate heat shrink, electrical tape, or label tube for insulation. I even often times use pliers/heat to de-insulate my forks and rings before use for personal projects (work stocks non-insulated forks and rings, so I don’t need to go there). Life is too short for crappy crimp connections.
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For wire-to-wire, Anderson connectors from Powerwerx.com, though we have bought some Andersons at AndyMark as part of another order. We only use automotive-style ring and spade style connectors as needed to interface with COTS components; we get these at a local auto shop. I prefer to buy robot electrical parts at the auto shop than a hardware or home improvement store, because they’re more likely to have been designed for stranded wire.
As noted above, the crimper is really the critical part! For Andersons, we use the tri-crimp. We haven’t found anything else which consistently produces good crimps that fit inside the housing.
Most of our bad automotive crimps have been made with a tool like this. The only thing we use those for is cutting machine screws; they’re actually pretty good at that*. We’ve had mixed success with non-ratcheting crimpers with a hard stop. If used properly, it works well, but sometimes students don’t squeeze all the way, especially on their tenth or twentieth crimp of the evening. We get consistently good crimps from a ratcheting crimper something like this.
- [edit]: To cut machine screws, thread the fastener with the head on the threaded side; then, when you back the screw out, the tool straightens the end thread automatically.
Yet again, the FIRST community as facilitated by Chief Delphi has been great in both the recommendations and timeliness. We can see more clearly now, the actions and tools needed to help fix our situation. We are excited to put these suggestions into practice without tossing our limited resources into other directions that might not be as fruitful. (As we have done sometimes in these early years of learning.) Thanks again!
In addition to tooling and supplies, you should also look at your training and inspection/acceptance process after the crimping is done.
For training, a good video like this one (shorter) or this one (longer) goes a long way toward showing what good crimping technique looks like. This presentation has an excellent section on crimping with photos.
Putting together a checklist will help ensure that terminals are attached properly. Have a second team member inspect each crimp immediately upon completion.
Some things to check:
- terminal is correct size for wire
- correct tool is available for terminal
- small amount of wire extends beyond the signal crimp - this helps prevent wire from being drawn from terminal
- correct location on terminal is crimped
- it’s not possible to pull the terminal off of the wire after crimping
If with grip wings
- signal grip wings are 100% in contact with wire
- mechanical (strain relief) grip wings are 100% in contact with insulation
If you are crimping battery wiring, search around on CD for threads dedicated to discussing that specifically.
Wonderful video resources and the checklist is tops. Thank you.