# Battery cable crimping



## evmetro (Apr 9, 2012)

I have a couple of long handle crimpers for my 2/0 battery cables, but the crimps always look like crap. I am really picky about how much resistance is in each of my connections, so I finally resorted to making my own tool.

Here it is in the rough, just enough to do a test crimp.










Here is a view of the backside










I built this to use on my 20 ton shop press, and it is really nice to be able to put a little pressure on the lug with the press, and then push the cable into the lug while pumping the press handle. I went ahead and loaded the full 20 tons onto this crimp to see how it did. here is what it looks like on the top










Here is the bottom. I was a little surprised that I was able to load it with the full 20 tons. Anyway, I don't know if this style of crimp complies with any kind of industry standards, but it is incredibly strong. I can feel that the strands near the lug are stiffer than what I am used to. 










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## Caps18 (Jun 8, 2008)

Could I send you my cables to crimp?  That looks really good.


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## evmetro (Apr 9, 2012)

Caps18 said:


> Could I send you my cables to crimp?  That looks really good.


Lol, and thanks. I still have to hook up a few of these cables in the car and test them under load to see how good the connection really is. The Orion shows the resistance of every connection on my dash display, and that is the only way I can tell just how good the connection is. I will post some results here in a few days when I get this rig back on the road.


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## onegreenev (May 18, 2012)

evmetro said:


> I have a couple of long handle crimpers for my 2/0 battery cables, but the crimps always look like crap. I am really picky about how much resistance is in each of my connections, so I finally resorted to making my own tool.
> 
> Here it is in the rough, just enough to do a test crimp.
> 
> ...


Sweet little device. So, do you put it in your hydraulic press? I just use a nice hammer crimper. I have been very pleased and have had not problems with mine. I did some testing using the hammer crimper and a good solid heavy metal base and a 4# sledge will do the trick with about three good whacks. I even cut them to have a look at the ends after a hammer crimp and one with a typical Hydraulic crimper. 

I don't think there is any industry standard. But Im sure there is something that many large manufacturers use to get consistent crimps. I think most of the hex crimpers are used for pretty. Not functional. Yes, they do work but I like a bit tighter crimp. 

Pete 

In the vid I say 5 good whacks but that is not really needed. Three good solid whacks is good. The crimp I used to show between a hydraulic crimp and a hammer one is not actually a true hex but it was a hydraulic crimp. Those kind are usually done two or three times but not in the same spot. I like mine better. If you do use a hammer on those thick type of crimps you need to give the top and bottom a tiny amount of lube to keep from tearing the thick copper. The thin lugs don't need that lube. The amount of lube on those think lugs is very minute. A little goes a long way. This test was also a good test of how well those thick style lugs work with a hammer crimper. Those do need a good solid 3 to 5 whacks. They are rather thick but they can be used if you have a manual crimper.

I await some more test results of your crimper. After you cut your crimps for visuals do some sanding and even a good wet sand would show the ends better than a coarse cut with no sanding. But that one crimp shows rather lousy crimp even with a rough cut. No sanding or etching of the end.


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## Duncan (Dec 8, 2008)

Hi Onegreen

I see your hammer crimper in the picture
I have one just like it - even the same color 
But I use it in my 12 tonne press the way Evmetro is doing

It seems to go in a lot further - I will have to take some pictures


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## evmetro (Apr 9, 2012)

Duncan said:


> Hi Onegreen
> 
> I see your hammer crimper in the picture
> I have one just like it - even the same color
> ...


That is an interesting idea, putting the hammer crimper in the press. I was completely unaware that a crimp lug like this would take the full 20 tons of force. I was trying to see where the limit was, so I could weld a stop onto this jig, and figured it would be destroyed with the full 20 tons. I did build this out of some really thick steel. I took a lug over to my local metal mart and held it up to various scraps until I found the maximum thickness that I could use, and bought enough so that I could screw up a few times.

I have an anvil style hammer crimper, a rocker style hammer crimper, a Klein bolt cutter style crimper, and another bolt cutter style one with a rotary die, and I can't seem to get the right crimp out of any of them. I might try putting my hammer style on the hydraulic press like you are saying.


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## evmetro (Apr 9, 2012)

Greenev, yes that was done on my hydraulic press. That was a great video of the hammer crimp, and I will probably cut one of my connections like that so I can see inside. I plan on opening the ends closest to the bolt hole to tig the strands to the lug as well, but that is past the crimp where the strands are a little looser. I want to open it up right on the crimp itself to see it like you did.


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## Duncan (Dec 8, 2008)

Pictures of the crimps I get,

I'm using old unlabelled ends and cables so - not good practice but I do seem to get a pretty fierce crimp


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## evmetro (Apr 9, 2012)

Ok, I went ahead and cut open that test crimp. I think I can live with this set up.










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## onegreenev (May 18, 2012)

Duncan said:


> Pictures of the crimps I get,
> 
> I'm using old unlabelled ends and cables so - not good practice but I do seem to get a pretty fierce crimp


Duncan,

Wow, That is a serious crimp. Might not want to go so drastic. Im thinking that it might just squeeze it so tight it would pinch it off and then that would be no good either.


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## onegreenev (May 18, 2012)

evmetro said:


> Ok, I went ahead and cut open that test crimp. I think I can live with this set up.
> 
> 
> 
> ...


That is a great looking crimp. I think its important to see the actual results so you know what your getting. I did get a crimp from a prior build that was the thick copper style crimp and done on a real Hex hydraulic crimper. I was able to just pull off the crimp. Slipped right off. No wonder the previous owner had issues. 

Cant wait to see the final result of your crimper.


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## Duncan (Dec 8, 2008)

onegreenev said:


> Duncan,
> 
> Wow, That is a serious crimp. Might not want to go so drastic. Im thinking that it might just squeeze it so tight it would pinch it off and then that would be no good either.


The cable I got has lots of very fine wires - I have been a bit brutal with one for a test and I couldn't manage to shift/break any

Be interested to see what your cables look like using the hammer crimper in a press


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## mizlplix (May 1, 2011)

It is most important to use ends with the correct size hole to get the most area under the nut. It does decrease the connection temperature in high amp usage.

Also, shrink sleeve the ends and you're good to go.

Miz


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## evmetro (Apr 9, 2012)

Round 2. I made a really beefy crimper that I can use in the shop press, or with a sledge hammer.










I have messed with various shapes for the crimp now, and this latest one has a v shape that gets narrower than the original diameter of the lug. Here is what it does:










Here is a cutaway view. Notice that it is a little taller than the first one, and not quite as wide.










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## onegreenev (May 18, 2012)

Nice looking crimp and crimper. Got any more ideas for the shape of the crimp? Looks to provide plenty of squish to make a good solid connection.


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## Duncan (Dec 8, 2008)

I've been thinking about the "shape" of the crimp

We start off with a thick walled tube
What we are doing is stressing the tube until we go into the plastic zone so that when we relax the crimper the "elastic spring back" of the tube is less than the spring back of the cable

I think that means that a "deeper" crimp like your last one will give more residual load clamping the cable in


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## EVfun (Mar 14, 2010)

I use the common hex crimper that looks like a large bolt cutter. I know I can put a single crimp on a 1/0 cable in a quality heavy copper terminal and put the cable over a large nail in my garage ceiling and then hang my weight from the cable without any movement. The terminals are crimped twice for installation. The sealant lined heat shrink makes a better seal onto the terminal with a hex crimp. That would be my main concern with a dimple crimp.

That said, it looks like you have managed a very quality crimp with that press tool. If you cut the lug apart lengthwise, to free it from the end of the cable, you can see how the individual fine strands are smashed. I know the hex crimper leaves the tiny strands with hex shape. I'm betting you will find the same.


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## evmetro (Apr 9, 2012)

EVfun said:


> If you cut the lug apart lengthwise, to free it from the end of the cable, you can see how the individual fine strands are smashed. I know the hex crimper leaves the tiny strands with hex shape. I'm betting you will find the same.


That is a good idea, I think I will cut it open like that so I can see how they are packed. I have been tracking and fighting connection resistance for a long time now, and often find bus bars or cables that look very solid, feel very solid, and are bolted solid, but it just has a little more resistance than I like. Occasionally, I can re crimp that cable and get a lower resistance under heavy load, but it seems like my long handle crimpers just can't squeeze the lug tightly enough. I enjoy viewing the highest and lowest resistance values when I am driving down the road, but seeing a big delta is torture. It is amazing what a less than perfect crimp does to the delta.


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## evmetro (Apr 9, 2012)

Duncan said:


> I've been thinking about the "shape" of the crimp
> 
> We start off with a thick walled tube
> What we are doing is stressing the tube until we go into the plastic zone so that when we relax the crimper the "elastic spring back" of the tube is less than the spring back of the cable
> ...


That was my thought as well. Shallower and wider like the first one should be weaker in the middle as far as bulging force goes. I had to make the bottom of the opening in the bottom jaw narrower than the original diameter of the lug, so the upper anvil forces the lug down to the bottom before it squashes it.


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## onegreenev (May 18, 2012)

EVfun said:


> I use the common hex crimper that looks like a large bolt cutter. I know I can put a single crimp on a 1/0 cable in a quality heavy copper terminal and put the cable over a large nail in my garage ceiling and then hang my weight from the cable without any movement. The terminals are crimped twice for installation. The sealant lined heat shrink makes a better seal onto the terminal with a hex crimp. That would be my main concern with a dimple crimp.
> 
> That said, it looks like you have managed a very quality crimp with that press tool. If you cut the lug apart lengthwise, to free it from the end of the cable, you can see how the individual fine strands are smashed. I know the hex crimper leaves the tiny strands with hex shape. I'm betting you will find the same.


Interesting idea. Never thought of cutting that direction. Well, since Metro will do that I will just see what his shows. Yes, some of the hex crimps can hold the weight but does not mean its a good crimp. What Metro is doing is good. Checking the resistance is a good thing. A good way to tell if your crimp is good. I still think you can over crimp and just melt your crimp and wire to the plastic point and just pinch it off or weaken it enough to cause trouble later down the road. Im sure there is a ideal point for a crimp.


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## evmetro (Apr 9, 2012)

onegreenev said:


> Interesting idea. Never thought of cutting that direction. Well, since Metro will do that I will just see what his shows. Yes, some of the hex crimps can hold the weight but does not mean its a good crimp. What Metro is doing is good. Checking the resistance is a good thing. A good way to tell if your crimp is good. I still think you can over crimp and just melt your crimp and wire to the plastic point and just pinch it off or weaken it enough to cause trouble later down the road. Im sure there is a ideal point for a crimp.


I am not knowledgeable about the plastic point. What is this? I saw somebody else mention that too.

I really like what you posted the other day about breaking the strands. I looked in the back side of all of my test crimps, and have not been able to find any broken strands. I will do that lengthwise cut that evfun was talking about though, and see what else I can see.


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## dcb (Dec 5, 2009)

Just my $0.02, most of the thinking has been done for you with a hex crimper, just need the right color connector and use the right die to cold weld that mess together.

A hydraulic unit is like $50 for 16 to 300 mm^2 http://www.diyelectriccar.com/forums/showthread.php/50-16-ton-hydraulic-hex-crimper-137313.html

"supposedly" makes the best electrical connection. I think they look the best anyway
http://www.windpowerengineering.com/design/electrical/matching-connectors-to-wind-turbine-cables/

add any dielectric after crimping, don't want that between your copper connections. Color coded heatshrink is a nice touch.

https://www.youtube.com/watch?v=b9MUfemfZY0


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## evmetro (Apr 9, 2012)

Ok, I went ahead and sliced it up, lengthwise. First, here is how it looks where the strands enter the lug.

Bottom side:










Here is the crimped side:










Here it is after I sliced it. This view is of strands that were on the bottom side.










And here is how the strands look on the stressed side. The only broken strands that I was able to find were the ones at the bottom of my cut, but those are from cutting past the lug. The creased strands are from the bottom of my crimp, where the flat part of my anvil hits it. Maybe I can keep the same shape and width of the anvil but add a little depth to it so that I can still maintain that long area of crimp. I like spreading the crimp over as much of the length of the lug as possible, so I don't want to just round the edges of the existing anvil to smooth that crease area of the strands, or it will decrease the length of the crimp. 










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## evmetro (Apr 9, 2012)

I have a cable that is routed through the car, so I can't get any of my new crimpers to work on the car. I dont want to swing the sledge in there either, so this one just uses some big ass bolts, one on each end. I can't drive either of the two end bolts more than a few turns, since I want to keep the upper bar somewhat level, but this set up makes a kick ass crimp inside the car with no shop press or hammer.










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