lug crimp, hex vs indent - Page 1
Forum section: electronics / general

author: coppercone2
author_rank: Super Contributor
timestamp: April 28, 2020, 06:53:19 am
content: What has a lower electrical resistance and higher stability, hex or indent crimps?

author: langwadt
author_rank: Super Contributor
timestamp: April 28, 2020, 08:48:14 am
content: how long is a piece of string?

author: PTR_1275
author_rank: Frequent Contributor
timestamp: April 28, 2020, 09:10:13 am
content: Personally I don’t like indent crimps.It comes down to the quality of the crimper (dies) though. I’ve seen people crimp battery cable with a coax crimper “because they’re all the same anyway” and I’ve seen people “crimp” by sticking a lug in a vice and hitting it with a cold chisel.For battery cabling I have an Izumi cordless hydraulic crimper. In my previous job it was used daily and was such a time saver. Nice crimps and quick.After leaving that job I’ve not been able to bring myself to sell it. The 3 times a year I use it is worth more to me than the money I could get from selling it.I’ve read quite a few documents on compliant crimping for larger cables and I don’t recall seeing anything about indent crimping. That could be because I wasn’t looking for it, but it might not exist.

author: PTR_1275
author_rank: Frequent Contributor
timestamp: April 28, 2020, 09:12:13 am
content: It also depends what size cable. I instantly assumed from your question that you’re asking about larger cables (25mm2 and above). If you’re talking about tiny cables, then TE / Deutsch crimpers (made by daniels manufacturing) are a 4 indent crimper and they are quite nice

author: coppercone2
author_rank: Super Contributor
timestamp: April 28, 2020, 02:52:48 pm
content: like 4awg+Has anyone done thermal tests, I know resistance is kind of hard to measure, but just with a Ti and a load to see which one runs coolerI found alot of analysis but no resistance or thermal measurement. Hard to make a choice because there is no data. The idea is to have a colder connection when the crimp is pushed to ampacity limit in steady state (resistive heating unit).

author: PTR_1275
author_rank: Frequent Contributor
timestamp: April 28, 2020, 03:06:02 pm
content: I’ve done comparisons in the past, but there was no noticeable difference at the time of crimping. The differences start to occur later on in the connections life. I tried to accelerate it but other things came up and I never got back to it, so unfortunately I can’t give any proof one way or the other.Cabac (an Australian lug and cable accessory supplier) have a few datasheets on the topic, but it’s mostly a dig at lugs that don’t confirm with Australian standards and to ensure your tooling matches the crimp.TE also have quite a few documents on compliant crimping. I also remember reading some white papers quite a few years ago, but I wouldn’t know where to begin looking for them.

author: coppercone2
author_rank: Super Contributor
timestamp: April 29, 2020, 04:05:55 am
content: there is one document with a thermal camera that shows from a battery manufacturer that the best heat results are from crimped AND soldered. But no details on what crimp to use. For a static cable it makes sense, but maybe not for a welding cable you connect and disconnect.Does anyone know if you should crimp then solder or crimp the solder? I would say #1.. but now sure how.. There is another document that shows a hex crimp is not really gas tight, but indent or X crimp is.. so I assume the solder helps the most with the non gas tight crimp, or increases surface contact area since it goes into uncrimped regions, but also won't it work against the crimp in terms of tempco to loosen it, since a good crimp will be done with EP copper lug and wire?https://www.trojanbattery.com/pdf/WP_BatteryCableGuide_0512.pdf

author: Electro Detective
author_rank: Super Contributor
timestamp: April 29, 2020, 06:20:59 am
content: I usually IPA clean and force fill the crimp space up completely before crimping,then crimp down with whatever method works,mechanically test it first, no movement or shifting aboutthen if it's a batch job, I will test one or two crimps with ludicrous current and note any hot spots if anyFor low current/low voltage stuff, loads easier tocrimp first then solder, walk away and never revisit

author: langwadt
author_rank: Super Contributor
timestamp: April 29, 2020, 12:03:41 pm
content: Quote from: coppercone2 on April 29, 2020, 04:05:55 amsoldering a crimps is bad enough, but you should never crimp on solder because solder cold flows so it gets loosesame goes for screw terminals

author: Electro Detective
author_rank: Super Contributor
timestamp: April 30, 2020, 12:33:05 am
content: crimping or screwing down on soldered wires is an unbelievableNO NO NO!You may get away with it on low voltage/low current stuff for a whileI've seen 3 phase connectors barbequed to a crisp because the unaware person thought to do a better tidy job of it,and not risk wire strands going everywhere, by soldering first then screwing downSolder first and crimped welding cables is another no go, what a mess they become and difficult to strike up and get a good runand then chuck the blame on the welder and or weldorAFAICT soldered wires under crimp or screw down pressure keep compressing over time and do not bounce back or stay constant.Sooner or later that connection gets loose or wonky and you get issues and perhaps sparks you don't need, especially in high voltage high current situations

author: tooki
author_rank: Super Contributor
timestamp: April 30, 2020, 11:18:13 am
content: Quote from: coppercone2 on April 29, 2020, 04:05:55 amSoldering a battery cable in a high-vibration environment like a car seems like insanity to me. It’s almost inevitable that solder will wick into the cable, creating a high-stress area that doesn’t have added mechanical support.A proper crimp is a cold weld and should have practically no contact resistance. If there is, as they suggest in their thermal camera images, I’d suspect that the wire and/or terminal already had some oxidation before crimping.

author: coppercone2
author_rank: Super Contributor
timestamp: May 03, 2020, 08:57:03 am
content: https://media.digikey.com/pdf/data%20sheets/molex%20pdfs/tbo%20quality%20crimp%20handbook.pdfpage 18