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Old 06-26-2012, 08:00 PM
sabahtom sabahtom is offline
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Default DIY cell connectors - worth the hassle?

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.
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  #2  
Old 06-27-2012, 04:02 PM
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dougingraham dougingraham is offline
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Default Re: DIY cell connectors - worth the hassle?

Quote:
Originally Posted by sabahtom View Post
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.
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.
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  #3  
Old 06-28-2012, 04:52 AM
sabahtom sabahtom is offline
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Default Re: DIY cell connectors - worth the hassle?

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.
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Old 06-28-2012, 05:47 AM
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Default Re: DIY cell connectors - worth the hassle?

Quote:
Originally Posted by sabahtom View Post
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
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Old 06-28-2012, 08:19 AM
sabahtom sabahtom is offline
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Default Re: DIY cell connectors - worth the hassle?

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.
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Old 06-28-2012, 08:41 AM
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Default Re: DIY cell connectors - worth the hassle?

Quote:
Originally Posted by sabahtom View Post
Do you mean you drilled through the braid? This sounds like a much better connector than what I've got.
Yes, thru the flattened tube with braid inside of it and having been soldered. It is very much like the pro jobs Although they are likely punched holes. Get the solder well wicked into the tube and it prevents the drill from pulling strands in the braid.
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Old 06-28-2012, 09:24 AM
adeyo adeyo is offline
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Nice...can we see pictures?
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Old 06-28-2012, 10:43 AM
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Default Re: DIY cell connectors - worth the hassle?

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Originally Posted by adeyo View Post
Nice...can we see pictures?
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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Old 07-02-2012, 02:41 PM
wguinon wguinon is offline
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Default Re: DIY cell connectors - worth the hassle?

Some use braid and avoid solid copper connectors to prevent strains on the battery terminals.
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