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DIY cell connectors - worth the hassle?

3K views 8 replies 5 participants last post by  wguinon 
#1 ·
My set of cell connectors has been badly made (mostly because I trusted the guy making them to know what to do, I should have specced it out in more detail).

So I've got a whole lot of tinned copper braid. Worthwhile to get copper welding lugs and DIY it? I guess the process would be to
1. remove the current tabs
2. get the copper lugs tinned
3. solder and crimp them.
 
#2 ·
I have considered a DIY approach for this but it just doesn't seem worth it. The approach I was considering was finding some copper tubing of the correct diameter such that when flattened would have the correct width. 1/2 inch tubing would have a circumference of 1.57 inches and when flattened would be half that or 0.79". A 3/4" tubing would be 1.18" wide when flattened. Just stick the braid in the tubing cut to the length you need and then flatten in a smooth surface vice. Drill the hole you need in the correct place and then tin plate the whole thing.

Or you can just buy them:

http://evtvshop.projectooc.com/products.php?cat=7

Copper lugs look like they are made by compressing tubing that is the correct size in a mold so a very similar process. You can buy a lot of tubing for the price of lugs. The tin plating is the only thing that in not cheap to set up to do.
 
#3 ·
I've got some free time coming up so hope to get the EV done. I don't want to pay shipping from Australia to get connectors from evworks there, since I'm going to Perth anyway in August.

If I use the braid that I've got now and change the lugs for crimped copper tubing, solder it up, how long will they be good for? If they'll last 3 months I'll probably do it this way.
 
#4 ·
I've got some free time coming up so hope to get the EV done. I don't want to pay shipping from Australia to get connectors from evworks there, since I'm going to Perth anyway in August.

If I use the braid that I've got now and change the lugs for crimped copper tubing, solder it up, how long will they be good for? If they'll last 3 months I'll probably do it this way.
Hi saba,

If you're talking about reusing the braids from these:


Once you remove the crappy steel ends, I think the braid will be too short for application of a proper copper end made from tube.

I have made custom braided connectors from braided strap and copper tube. It came out pretty good, but not near the quality of a pro factory product. I had the braid fill the entire length of the 3/4" piece of tube. Flattened it in a hand press. Then sweated in solder with a torch. Then drilled it. Then filed the surfaces flat.

I didn't tin or plate the bare copper surface on the end tabs. It isn't necessary for function, but desirable to prevent corrosion, but that takes a while.

You'll have trouble reusing those straps, but WTF, you got 'em and got the time. Good luck.

major
 
#5 ·
Hi Major

Thanks for that detailed reply.

I had the braid fill the entire length of the 3/4" piece of tube. Flattened it in a hand press. Then sweated in solder with a torch. Then drilled it.

Do you mean you drilled through the braid? This sounds like a much better connector than what I've got. I see the pro factory ones seem to be done that way, with the tabs being full of braid.
 
#8 ·
The braided ones are inside these EVs :)



Each bike has 2 of the braided connectors used to connect battery packs. I didn't get photos of the connectors. But here are a couple of shots of how I made laminated connectors for another project.





Regards,

major
 
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