Heat Shrink habit

[Jay05]

This year after a catastrophic short circuit blew 2 victors I have gotten in the habit of heat shrinking crimp connectors on to the wire. Basically I crimp the hell out of the connector and then shrink a 5 inch piece over the connector and wire. Is this common practice for anyone else?

[sanddrag]

You shouldn't "crimp the hell out of the connector." You should use automatic crimpers with the proper die or setting for the kind and size of connector you are using. Also, only strip enough wire to fit inside the metal part of the crimp connector, and the connectors housing and the wire insulation will prevent any shorts. If you are using open (uninsulated conectors) you should use a little bit of heat shrink to cover it. But, in any case there is no need for 5 inches of the stuff.

PS: with crimping it also helps to use a higher quality more finely stranded wire than FIRST currently gives us.

[Dave Flowerday]

Originally posted by Jay05
Basically I crimp the hell out of the connector and then shrink a 5 inch piece over the connector and wire. Is this common practice for anyone else?

Like Sanddrag said, it's not really a good idea to "overcrimp" the connectors on to the wire. You're much better off crimping the wires normally and then soldering the connection. I can't emphasize enough how worthwhile it is to spend the minute or two soldering each connection on your robot. If you need removable connections like in this case, then solder the connector to the wire. For connections that don't need to be taken apart, just twist the wires together and solder that (don't forget to slide some loose heatshrink on the wire first to pull over the connection after it's soldered!) Heatshrinking over the connectors is always a good idea too.

[Andy A.]

I wouldn't call it common practice, but its not rare. If the crimp is done correctly (assuming it's a insulated crimp), you shouldn't need to. But, there isn't anything wrong with doing it, especially if for some reason the crimp leaves metal exposed. It sure looks better then tape. If it's an exposed crimp, then heat shrink is mandatory (tape falls off, and just looks ugly).

I'll usually only heatshrink crimps that may get moved a lot or are exposed (like motor leads). It helps stiffen the wire a little and covers the more heat sensitive insulation. For the other hundred crimps on the bot, I don't see it as necessary.

If you don't mind using up your heat shrink, then more power to you, but 5 inches is way excessive.

-Andy A.

[Al Skierkiewicz]

To sum up the best of all the posts...
A good crimp made with the right tool on the connector the tool was designed to crimp for the right size wire, will be an excellent connection. Unfortunately, our teams are not using the same crimper with the correct connector for every wire and with non-automatic crimpers, the level of crimp depends on the forearm strength of the person doing the crimp. A soldered connection (when done properly) will fix most problems with the strip and crimp operation. Since, soldering requires a non-insulated connector, heatshrink is a must. The drawbacks with soldering are 1) a need to have a correctly sized and powered iron, 2) good mechanical contact 3) both the wire and connector need to be hot enough to melt solder, 4) and just enough solder applied to the joint that it doesn't wick up inside the wire and make the wire stiff and unmoving.