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Tim_the_bloke Senior Member Joined: 15/11/2009 Location: AustraliaPosts: 105
Posted: 10:07pm 22 Mar 2017
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I need to make up some new battery cables. What is the best method?
This is an image of one of the lugs with a $1 coin for scale.
Should I solder the battery lugs onto the cable? If so how? Should I crimp, then solder, then cover with heatshrink? Should I add some electronic solder into the join cold prior to crimping, then heat the lug with a propane torch? Surely soldering will melt back the cable's insulation? Should I just crimp? Edited by Tim_the_bloke 2017-03-24
mackoffgrid Guru Joined: 13/03/2017 Location: AustraliaPosts: 460
Posted: 11:09pm 22 Mar 2017
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A definite no no is to apply solder before crimping
my two bobs worths; Best is to use a good crimping tool - I use a hydraulic crimp tool off ebay. Soldering can work if you have a powerful soldering iron or appropriate gas torch.
Solar Mike Guru Joined: 08/02/2015 Location: New ZealandPosts: 1138
Posted: 11:39pm 22 Mar 2017
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Crimp, always; a soldered joint on heavy cable is going to fail, heat in the joint melts the solder, which causes a higher resistance, so more heat... so can see where this is going.
Cheers Mike
Tim_the_bloke Senior Member Joined: 15/11/2009 Location: AustraliaPosts: 105
Posted: 11:54pm 22 Mar 2017
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So don't even try to solder after crimping?
Solar Mike Guru Joined: 08/02/2015 Location: New ZealandPosts: 1138
Posted: 12:47am 23 Mar 2017
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Pointless, a high pressure crimp results in an effective welded bond, then all your solder and heat is going to melt the insulation and wick solder into the cable making it less flexible.
Tim_the_bloke Senior Member Joined: 15/11/2009 Location: AustraliaPosts: 105
Posted: 12:57am 23 Mar 2017
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That makes sense. Thanks.
Boppa Guru Joined: 08/11/2016 Location: AustraliaPosts: 814
Posted: 04:55am 23 Mar 2017
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Many moons ago as an apprentice, we had to make a crimping tool to use with a vice- two bits of 1" thick steel, bit of work with a grinder and file to make the correct size hole and shape and bingo one tool- just place in vice and crush to get the crimp
Out bush, one trick is to get a small bolt or drill (2-5mm depending on size of the lug), put it against the crimp and crush in vice (or hit with hammer if no vice or in one case the bottom of the cars bottle jack!)- good for emergency repair at least and also works remarkably well with practice
but with the cost of the crimpers on ebay, for the occasional use, just buy the bolt cutter style crimpers
I never solder after crimping- it tends to wick up the cable and esp on trucks and heavy machinery, often the cable starts to `crack' at the end of the solder- often within a few weeks on offroad machinery like bulldozers!
Also a good idea (esp with lead acid batts, not so much with more modern ones) is get some red and black heatshrink to go over the ends- the type with heat setting glue on the inside and seal up the ends with it- prevents any acid fumes or water getting inside the insulation and `blackening' the copper- which will often cause high resistance joints, and shows the polarity when using lugs rather than battery terminals
Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406
Posted: 01:13pm 23 Mar 2017
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I would crimp, simply because its fast, and I have an enormous and rather expensive crimp tool.
But I would have no hesitation in soldering as long as the crimp lugs are fairly new and not oxidised. Resin cored solder will work fine.
Easiest is probably to use a small propane torch, if you are really struggling it can be done over the kitchen gas stove, if you are careful not to burn the plastic insulation. Just hold the end of the lug over the flame (not right in it) and let the heat slowly conduct into the wire.
It will look a lot nicer crimped or soldered if you put some red or black heat shrink over the end.
A few years ago I had some problems starting a thirty year old car. The problem turned out to be all the original factory crimped lugs in the heavy battery and ground wires to the starter had gone high resistance. These were cut off and new lugs soldered onto the wires. For something exposed to a very harsh environment, soldering might be more long term reliable than a crimp because it keeps air and moisture out.Cheers, Tony.
Notice. New forum software under development. It's going to miss a few functions and look a bit ugly for a while, but I'm working on it full time now as the old forum was too unstable. Couple days, all good. If you notice any issues, please contact me.
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