Crimping Battery Cables

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capricorn

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I'm intending to make some changes to my battery set up this winter (seperate domestic bank switched via rotary switch etc).

What's the best way to attach connectors to battery cables, should I solder/braze or crimp the connectors to the battery cables. If the later, I assume I need a crimper desined for automotive battery cables. Where can I get one of these and is is cost effective to buy one for one off use or can I hire one from HSS or somewhere ?

Thanks in advance as always !
 
Depending on what sort of local garage you have. If it's not the old fashioned sort, find an auto-electrician, or, and this is a tip for all of you, some one who fits tail-lifts to wagons. The kit comes with metres of battery cable and if they are refitting a tail-lift or simply have spare cable they usually keep it and sell it in long lengths El Cheapo. I got enough to do a Mini for £5.

Alternatively wack the terminal shroud lengthways with a bluntish cold chisel, that's all the crimper does, but a bit more genteel. If you can lay it in a groove first ( or contain it in mole grips) to stop the sides splaying out it will be perfect. Honest.
Don't forget to do a HSE risk assesment first /forums/images/graemlins/cool.gif
 
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Alternatively wack the terminal shroud lengthways with a bluntish cold chisel, that's all the crimper does, but a bit more genteel. If you can lay it in a groove first ( or contain it in mole grips) to stop the sides splaying out it will be perfect. Honest.
/forums/images/graemlins/cool.gif

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Above is no substitute for using the correct crimping tool - the previous owner of my boat adopted the above solution but the cables pulled out with little effort. A proper crimper applies pressure on all sides along a substantial length of the end fitting. I suppose this may also improve electrical conductivity. /forums/images/graemlins/wink.gif
 
There are bodgers and there are bush-mechanics. He was obviously a bodger. /forums/images/graemlins/wink.gif

The first part of my reply however will get the job done well at a fraction of the retail cost.
 
I have a crimper which, while it won't do the main battery terminals, it is fine for anything up to 1/4" or so. It's about 18-20" long.

If you go down the M3 to your boat, you're welcome to pop past Twickenham and borrow it.
 
You can buy lugs which use a couple of allen screws that tighten down on the cable. Dip the cable end in vaseline first. Then you dont need a crimper and can reuse the lugs or change the cable if you ever want to.
 
There are hammer-on terminals made for welding cable capable of carrying hundreds of amps continuously. They are considerably heavier than crimp-on terminals.

City Electrical Factors used to hire out crimping tools but if they supplied the cable lugs they might be persuaded to squeeze them on for you ?

A friendly electrician may be helpful - once the cables are prepared its a two minute job. Clean off all the flux afterwards and protect from corrosion with tape.

There is an alternative method sweating (soldering,with flux) the ends on - cheaper yet use a bit of scrap copper pipe.
 
Screw downs .... at last sanity !!!

A post above mentions tail-lifts .... well blow me down - I've just had mine serviced and guess what ..... not a crimp in sight .... When asked why not - service engineer said .....

"OK - yeh soime people still use crimps - but then you are stuck with them ... we changed to screw-downs - then if cable or other fitting needs work - easy ... plus haven't you noticed that majority of battery terminals are now screw-downs ... connectors get corroded .... break it off, clean up and fit a new screw-down .... not so easy with crimped ...."

Well that's what he said and I have used screw-downs where before I would have had crimped .... lasted years ....

I don't advocate that ALL connections can use them - sometimes space is not there - ie alternator / starter motor terminals etc. - then crimped has its benefits ......

One screw-down I saw has a point to each of the screws ... which literally push a hole bewteen the cable strands without breaking the strands ... increasing the overall contact etc. Got to be good !!
 
I use these on my battery cables and they did the job. They were about £40:


166676.jpg
 
Do it with a proper crimper.....most electricians will have or know some one who has one......anyone need a lug crimping in Lincolnshire ???

16mm and 25mm is the favorite sizes.....thats mm squared...don't know about this gauge stuff....?
 
For the best joint I still solder battery connectors. Use a torch to heat up the connector and pour the solder into the joint. After soldering, screw down can at least be pulled apart and cleaned when corrosion is bad. Crimped ones done properrly are good but I've seen too many where corrosion was hidden by the crimp. I'd be surprised if you could get a really good crimp on a normal battery cable without a hydraulic press.
 
We have just put in five batteries with switches, going out to starter moter and windlass etc. I used 50 sq mm cable and connectors which I soldered on. The solder incorporated acid free flux. I finished it off with a short length of heat-shrink tubing of the appropriate colour. It looks neat, should last for yonks and is certainly carrying the current.
 
to repeat an old response:
the problem with soldering connections is that if the connection gets hot there is a sporting chance that the solder will melt and the wire fall out - hence a mechanical connection (the crimp) is attractive. I do also recognise that this is a remote possibility if everthing is correctly specified.
 
I watched a marine electrician do it as follows :-
i) tinned the wire
ii) tinned the fitting
iii) crimped the lot (he put it through twice !)
iv) heated it all up and flooded it with solder
v) when cold he then put heat shrink on

turned to me and said " that's a proper job "
 
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