# How to crimp custom "ground straps"?



## roach374 (Jun 14, 2021)

I'm looking for information on where to buy the correct crimps, and how to correctly crimp, these types of ground straps, for inter-cell connections. My google-fu is not helping me much. I can find the right ground strap material, but not sure the right term for the crimps, or what crimping tool to buy. Can anyone help?


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## roach374 (Jun 14, 2021)

Seems like this may have already been answered in this wiki article!


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## john61ct (Feb 25, 2017)

See if genuinedealz.com will do them for you


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## lnstech (Nov 20, 2009)

Have you looked at these?















EVTV Motor Verks Store: Braided Battery Strap Kit - 76 mm centers, Battery Connections, braindedstrap76mm







store.evtv.me


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## roach374 (Jun 14, 2021)

lnstech said:


> Have you looked at these?
> 
> View attachment 122907
> 
> ...


That's EXACTLY what I'm looking for. Thanks!


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## StanStr (Jun 13, 2009)

The holes have 76mm centers, which is 3 inches, so I'm guessing they're about 4 inches long overall, and about 3/4 or 7/8 inches wide. A short length of 1/2" copper tubing can be easily hammered flat, and will be close to 3/4" wide. Cut to length and drill holes as you need them and you have a one piece connection strap. 

Google: make battery connector from copper tubing


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## john61ct (Feb 25, 2017)

Problem with rigid connections in a mobile use case

is all shock/vibrations between cells get transferred to the posts, very often not at all strong laterally, not designed to be structural.

Personally I'd stick to tinned fine stranded "boat cable" (UL1426 105c)

cut to length so no tension

and properly crimped.


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## brian_ (Feb 7, 2017)

Grote has braided ground straps with crimped-on ring terminals - they apparently just gather up the braid into a bundle to use a common crimp terminal. They don't anything short enough, but their products illustrate one way that they could be built.

The logic in favour of a cable connection make sense, but at this length a heavy round cable would have almost no flexibility, which is presumably the reason for wanting a flat braided cable.


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## john61ct (Feb 25, 2017)

Fine stranded boat cable is pretty flexible.

So long as there is a curve in the connection between posts, I do not understand why "more flexibility" would be desirable?


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## brian_ (Feb 7, 2017)

john61ct said:


> Fine stranded boat cable is pretty flexible.
> 
> So long as there is a curve in the connection between posts, I do not understand why "more flexibility" would be desirable?


Absolutely. But these straps are only 76 mm on centre, so the cable length with typical terminals is only about half that, and in the gauge of cable used for this that's almost a rigid bar, even in boat cable. I agree that a curve would be good, but it's hard to get a curve in that short distance.

Some people have used solid copper straps for this sort of application, but crimped a curve into the middle to allow some flex. There are even commercially available bus bar expansion joints, which use a stack of thin sheets (in aluminum or copper) for flexibility, welded to solid end bars.


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## john61ct (Feb 25, 2017)

brian_ said:


> it's hard to get a curve in that short distance


Wut?

You measure twice, cut once, crimp the ring terminals on, attach to the posts, voilà Bob's your uncle.

I cannot imagine how anyone would consider adding 2-3cm to the length "hard"?

Even with 00 AWG. . .


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