crimping "battery" terminals

[Simon]

I'm crimping some large barrel terminals like the ones commonly refered to as battery terminals. Do I correctly understand that it will be utterly hopeless to try a 25sqmm wire in a 35sqmm barrel ?


I'm thinking that I should pack it out.

[max_torque]

It really depends on the type of crimping tool you are using.  The large lever type single anvil tools can generally apply enough crush force to make it work, although the resulting crimp is far from neat and may not fully capture every strand of the cable (however this is seldom an issue for cables this large in general).  The more specalised multi anvil tools will simply not have enough crush force to squash the crimp down to capture a smaller cable that is recommended for that size.

One option is to strip back twice as much bare conductor as you need for the crimp, then cut off approx half it at half length, then fold back the remaining long strands to form a bulk bundle that is roughly 1.5x the size of the original.  You may need to experiment to get a nice fit / crush etc

[Benta]

Another option could be slipping a reduction ferrule over the cable strands.

[Simon]

yea, I borrowed a proper big crimp tool from work http://uk.rs-online.com/web/p/crimp-tools/0445611/?searchTerm=445-611&relevancy-data=636F3D3126696E3D4931384E525353746F636B4E756D6265724D504E266C753D656E266D6D3D6D61746368616C6C26706D3D5E283F69292852537C5253207C52532D293F5C647B337D285C73293F5B5C732D2F255C2E2C5D285C73293F5C647B332C347D2426706F3D313426736E3D592673743D52535F53544F434B5F4E554D4245522677633D4E4F4E45267573743D3434352D363131267374613D3034343536313126 and added some strands to bulk it up, came out fine.

[Simon]

Another option could be slipping a reduction ferrule over the cable strands.

Never heared of those.

[Benta]

Never heared of those.

Here's an example (German, I apologise):
http://katalog.klauke.com/de/aderendhulsen-nach-din-cu-0-25-240-mm-14134/

[Simon]

Ah right, guess it's just an aluminium tube of appropriate ID/OD with the flare to aid cable entry.

[Ian.M]

No. its tin plated copper. You wouldn't want an Aluminium oxide layer at the interface between the ferrule and the terminal.   I've made up similar ferrules from copper tube, flame annealed, and quenched in water so its dead soft then brightened with a pan scourer.  To make it easier to insert the cable cleanly, you can either flare the end slightly by hammering a significantly oversize ball bearing into it slightly and re-annealing, or open it out slightly with a fine round file or a mounted stone in a drill.

[Simon]

Well just adding some extra strands worked fine.

[Ian.M]

I had to rewire some cast brass terminals (Lead acid battery post type) with setscrews for retaining the cable.  As it was the 'house' battery the cable size was a lot smaller than the terminal was intended for.  The copper ferrules worked nicely and let me torque the setscrews down really tight (initially substituting a steel bolt with a carefully deburred and smoothed end to pre-form the ferrule and cable to the terminal then replacing with the brass setscrew).     

It sure beats 3rd world 'bush' mechanic tactics of hammering the crimp terminal as tight as you can get it then protecting the cable entry end with clay, dipping it in tree sap dissolved in Arak as flux and into an improvised solder pot: a small steel can filled with %DEITY% knows what SnPb alloy made from lead shot and tin capsules from wine bottles, in a clay pot of burning charcoal.