Can I spot weld copper strips?

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Can I spot weld copper strips?

Post by rg12 » Oct 11, 2017 11:05 am

Hey Guys,

I'm working with pure nickel right now and am in a search for an even more conductive material, so I thought about looking for a copper strip supplier.
I have a machine that can weld up to 0.15 pure nickel.
The question is, do you think that the same machine with the same power for welding 0.15 pure nickel can spot weld 0.1 copper?
Also, does copper corrode over time if it's not coated with tin like tinned copper wires?
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Re: Can I spot weld copper strips?

Post by 999zip999 » Oct 11, 2017 8:47 pm

Where you live ? I can see the Pacific right now. Salt air... So yes it will turn green over time. There are people here electroplating copper with a small battery and some I don't know vinegar or something. Copper low resistance, pure nickel High Resistance.

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Re: Can I spot weld copper strips?

Post by e-beach » Oct 11, 2017 10:29 pm

You will probably have to experiment a bit. Copper is softer (obviously) so you might have to tune down the amps on your welder. Or get thicker copper strips which will carry higher amps anyway. You might also get stranded copper wire and flatten it with a punch and use that to weld instead of strips. If you are crafty, measure the distance necessary to center-up you wire on the cells and only cut away enough insulation on the wire so you can flatten and spot weld the wire to you cells.

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Re: Can I spot weld copper strips?

Post by wturber » Oct 11, 2017 10:35 pm

rg12 wrote:Hey Guys,

I'm working with pure nickel right now and am in a search for an even more conductive material, so I thought about looking for a copper strip supplier.
I have a machine that can weld up to 0.15 pure nickel.
The question is, do you think that the same machine with the same power for welding 0.15 pure nickel can spot weld 0.1 copper?
Also, does copper corrode over time if it's not coated with tin like tinned copper wires?
I've read that copper doesn't weld as well precisely because it conducts electricity well. The resistance of the nickel causes the temperature to rise enough to create the weld. The copper supposedly will not get hot enough because it passes the current too easily. I have no direct experience with this, but recall reading that when I was researching building batteries. It seems plausible to me.
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Re: Can I spot weld copper strips?

Post by Willow » Oct 12, 2017 5:33 am

0.1 copper - using a spot welder with a big coil and a custom timing circuit. Good for as much as the cells can give.
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Re: Can I spot weld copper strips?

Post by ridethelightning » Oct 12, 2017 5:35 am

copper works great, providing it is thin enough, that you dont rely on it for mechanical strength to hold the pack together, and that you have a big enough spot welder with tungsten electrodes. oh, and keep it dry.
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Re: Can I spot weld copper strips?

Post by rg12 » Oct 12, 2017 8:20 am

I'm afraid of the corrosion thing...there is always a chance of humidity getting in...
I will need a bad ass spot welder for that I'm guessing because mine is maxed out when using 0.15 pure nickel.
Do you have any suggestions for a machine that isn't expensive from AliExpress that is strong enough?
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Re: Can I spot weld copper strips?

Post by Buk___ » Oct 12, 2017 8:43 am

rg12 wrote:Hey Guys,

I'm working with pure nickel right now and am in a search for an even more conductive material, so I thought about looking for a copper strip supplier.
I have a machine that can weld up to 0.15 pure nickel.
The question is, do you think that the same machine with the same power for welding 0.15 pure nickel can spot weld 0.1 copper?
Also, does copper corrode over time if it's not coated with tin like tinned copper wires?
One thing noone has mentioned in this thread, though it is discussed elsewhere, is the benefit of putting a slot into the strip where the spot weld will go, and positioning the welder tips either side of the split:
contactSplit.jpg
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The current will flow via the most direct path, and the split will force most of it to flow down through the battery contact and back up the other side, rather than mostly straight across through the copper as would be the case without the split.

A small diameter (or well worn) dremmel type cutting disc works wel for making the slot.

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Re: Can I spot weld copper strips?

Post by rojitor » Oct 12, 2017 9:37 am

https://endless-sphere.com/forums/viewt ... 14&t=89076
This welder is copper capable. I wrote quite a lot about it.
Also there's a thread about creating one with a m.o.t.
https://endless-sphere.com/forums/viewt ... 14&t=84680
If your welder does 0.15 nickel tops you are not even close to be able to weld copper.
It is way more dangerous and difficult. I did some packs with and without plating proccess. I think it is totally worth it.

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Re: Can I spot weld copper strips?

Post by wturber » Oct 12, 2017 10:56 am

Buk___ wrote:
rg12 wrote:
The current will flow via the most direct path, and the split will force most of it to flow down through the battery contact and back up the other side, rather than mostly straight across through the copper as would be the case without the split.
Is that the most direct path geometrically, or the most direct path from the standpoint of electrical resistance?
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Re: Can I spot weld copper strips?

Post by Buk___ » Oct 12, 2017 11:42 am

wturber wrote:Is that the most direct path geometrically, or the most direct path from the standpoint of electrical resistance?
I doubt electrons know Pythagoras :), so probably the path of least electrical resistance; but I don't think it wasn't meant as a statement of scientific principal.

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Re: Can I spot weld copper strips?

Post by rg12 » Oct 12, 2017 12:12 pm

rojitor wrote:https://endless-sphere.com/forums/viewt ... 14&t=89076
This welder is copper capable. I wrote quite a lot about it.
Also there's a thread about creating one with a m.o.t.
https://endless-sphere.com/forums/viewt ... 14&t=84680
If your welder does 0.15 nickel tops you are not even close to be able to weld copper.
It is way more dangerous and difficult. I did some packs with and without plating proccess. I think it is totally worth it.
Plating process is too much for me...maybe I can find a factory via Alibaba that can provide it plated.
What is the plating material btw?
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Re: Can I spot weld copper strips?

Post by rg12 » Oct 12, 2017 12:27 pm

rojitor wrote:https://endless-sphere.com/forums/viewt ... 14&t=89076
This welder is copper capable. I wrote quite a lot about it.
Also there's a thread about creating one with a m.o.t.
https://endless-sphere.com/forums/viewt ... 14&t=84680
If your welder does 0.15 nickel tops you are not even close to be able to weld copper.
It is way more dangerous and difficult. I did some packs with and without plating proccess. I think it is totally worth it.
That's amazing that this lipo can do whatever the big machines can't do.
Although I'm looking for something a little more professional and they mention that the device may not last the use of copper for long...
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Re: Can I spot weld copper strips?

Post by rojitor » Oct 12, 2017 12:40 pm

I electroplated my tabs with nickel. I couldn't find it for sale anywhere. Of course there is many sellers but as soon as you send they a mail they always reply: how many tons do you need? No one (so far) sells a few meters.
There's some sellers at ali supplying tinned copper. I didn't test it buy I have zero expectations on that.
My boss welder so far did very good job with copper 0.1 and even 0.2 but I stopped using 0.2 because it will cause premature failure of the machine.
0.1 is relatively safe. Copper is always more difficult and dangerous.

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Re: Can I spot weld copper strips?

Post by rg12 » Oct 12, 2017 12:49 pm

rojitor wrote:I electroplated my tabs with nickel. I couldn't find it for sale anywhere. Of course there is many sellers but as soon as you send they a mail they always reply: how many tons do you need? No one (so far) sells a few meters.
There's some sellers at ali supplying tinned copper. I didn't test it buy I have zero expectations on that.
My boss welder so far did very good job with copper 0.1 and even 0.2 but I stopped using 0.2 because it will cause premature failure of the machine.
0.1 is relatively safe. Copper is always more difficult and dangerous.
What do you mean by dangerous? the sparks?

also, where can I get it?
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Re: Can I spot weld copper strips?

Post by brumbrum » Oct 12, 2017 1:25 pm

Its more dangerous as you need more power to weld it, and usually rhat means stressing the spot welder by adding more voltage and potentially causing some fireworks.
A lot of people use the nickel to connect up only the cells in parrellel as there is no big amperage running through it. For series connections that carry the big amps it is possible to use tinned copper wire soldered on between each cell(in the gap where the cells stand against each other) so it is not directly above cell terminals and does not damage the cell with heat.

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Re: Can I spot weld copper strips?

Post by rojitor » Oct 12, 2017 2:55 pm

As brumbrum said. Since you need to rise voltage you get more heat and sparks. Gaps can make big holes. It requires full attention, gloves and glasses. Nickel is way easier to weld.

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Re: Can I spot weld copper strips?

Post by rg12 » Oct 12, 2017 3:13 pm

Can you really feel the difference while riding if you compare two identical packs that one of them is built with 0.15 pure nickel and the other is 0.15 copper?
Will the voltage sag improvement be noticeable?
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Re: Can I spot weld copper strips?

Post by rojitor » Oct 12, 2017 6:07 pm

Depends on many factors, voltage, kind of cells,bms... but Yes...it is noticeable.
My last pack (copper triangle) is the best I ever had. I will use copper mostly for sure.

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Re: Can I spot weld copper strips?

Post by rg12 » Oct 13, 2017 2:39 am

Sounds good
Where can I get that little LiPo spot welder?
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Re: Can I spot weld copper strips?

Post by rojitor » Oct 13, 2017 3:19 am

First post of the thread. Scroll down to disclaimer. Instructions there.

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Re: Can I spot weld copper strips?

Post by rg12 » Oct 13, 2017 4:48 am

Thanks alot :)
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Re: Can I spot weld copper strips?

Post by rg12 » Oct 14, 2017 12:14 pm

rojitor wrote:First post of the thread. Scroll down to disclaimer. Instructions there.
Talked to the guy and he said that you actually did weld 0.1mm copper but he also said that he doesn't recommend it.

I'm buying this only for the purpose of welding 0.1mm copper.
Will it last?
Can you weld copper with copper electrodes? because I've seen that the big machines for copper use tungsten electrodes...
Can I use tungsten in this thing?
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Re: Can I spot weld copper strips?

Post by spinningmagnets » Oct 14, 2017 5:15 pm

The reason to use tungsten is because they will not get soft and stick to the copper. They will get very hot, but they will work if you like them.

If the copper electrodes are thicker than the bus-strips, they will get very warm, but they will not be as hot as the contact points on the buses.

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Re: Can I spot weld copper strips?

Post by rg12 » Oct 14, 2017 5:49 pm

I just read some more threads here about spot welding copper and it turns out that the 0.1mm copper is super soft to hold the pack together.
It's hard enough to find a machine for 0.1mm copper but 0.2mm copper is for a machine that costs over 10k.
Isn't there a cheap machine that isn't like the Orion 250 that can just pass a sh** load of current for a few ms and solve this problem? why are all the machines so weak while a 3S lipo spot welder can do what a huge microwave transformer can do?
I don't get it...
I don't need a super high tech machine with color touch screen...
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