18650 spot welding -how to- ULTIMATE REPOSITORY

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Post by joss » Feb 05 2016 10:21pm

douglashart wrote:nickel is nonferrous , thus non magnetic. Put a magnet to it, if its magnetic , its steel.
Right/Wrong Nickel is non ferrous but definitely ferromagnetic (is is attracted to magnets). :roll:

Please check your sources!

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Post by nippynoo » Feb 08 2016 5:20pm

mistercrash wrote:
eTrike wrote:Nickel is cheap, easy and corrosion resistant
Zinc is corrosion resistant and a lot cheaper than Nickel. Look at the prices I posted above. It also offers less resistance than Nickel. Is there a Metallurgist in the house? :lol:
Could be something to do with the Standard Electrode Potential when two dissimilar metals are connected. Metals higher in the electrochemical series displaces metals lower in the series, which means that when connecting two metals the metal with the lowest potential corrodes.
  • Nickel is -0.24V S.E.P
    Iron is -0.44
    Zinc is -0.76
Battery cases are usually made from steel, which is iron. Given that Nickel and Zinc are higher and lower than iron, respectively, they exhibit different corrosion and a (thin) zinc strip would corrode and eventually be eaten away (at an increasing rate), when welded to the steel case, because its lower SEP than iron.

Nickel however would remain unchanged, so would be more reliable, as its the relatively thick iron that is sacrificial, but theres lots of iron.

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Post by joss » Feb 08 2016 6:32pm

I received some pure nickel strip in the post yesterday so I decided to do a short video showing the corrosion performance difference between this and the steel/nickel plated version I received a few weeks ago.

https://youtu.be/1r2tkwUnNv4

...now looking forward to putting my new battery pack together!

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Post by tomjasz » Feb 09 2016 12:56am

Man you guys! I'm never gonna dump this kg of nickel plated...
Thanks Justin_le we're here thanks to you. All the best to the mods for their tireless work keeping it on an even keel.

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Post by DVDRW » Feb 09 2016 2:09am

Pure nickel strip seems pointless to me.
Nickel plated is 0.18mm thick
Pure nickel is 0.1mm thick and 2x more expensive
So current capability is about same?
You throw battery pack away anyway after few years when depleted before strip corrosion starts.

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Post by tomjasz » Feb 09 2016 2:27am

DVDRW wrote: So current capability is about same?

NO!
Thanks Justin_le we're here thanks to you. All the best to the mods for their tireless work keeping it on an even keel.

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Post by okashira » Feb 09 2016 2:55am

joss wrote:I received some pure nickel strip in the post yesterday so I decided to do a short video showing the corrosion performance difference between this and the steel/nickel plated version I received a few weeks ago.

https://youtu.be/1r2tkwUnNv4

...now looking forward to putting my new battery pack together!
Great video. My old first strip for the Chinese holders was in fact from BGTFL :)
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Post by joss » Feb 09 2016 6:06am

tomjasz wrote:Man you guys! I'm never gonna dump this kg of nickel plated...
I reckon my kg is destined to be a door stop (and a rusty one at that)!

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Post by tomjasz » Feb 09 2016 12:09pm

joss wrote:
tomjasz wrote:Man you guys! I'm never gonna dump this kg of nickel plated...
I reckon my kg is destined to be a door stop (and a rusty one at that)!
Worse story here...Mine was added to a spot welder, 709A hat fried on the second weld, now have a 709A with new PCB and replaced parts that to expensive to have repaired. I can't even get a buyer to pay the cost of the new PCB shipped from China, $100. Thank goodness for JP!!
Thanks Justin_le we're here thanks to you. All the best to the mods for their tireless work keeping it on an even keel.

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Post by Nobuo » Feb 09 2016 2:37pm

bikegeek wrote:I've done the test once again but this time with salt, vinegar and hydrogen peroxide. You can see the result in the pictures.

The two small ones (0.1x5mm) are the same and pure nickel, the big one (0.15x8mm) has an area that under the liquid it rusts but when I pull it out the rust washes away. And is remaining only a mat grey area different than the nickel from the surface. Is this steel? Why is not remaining rusty out of the liquid?

What is the problem if I weld with that?
You should only use salt water, as nickel hydroxide decompose hydrogen peroxide you could have confusing rust over the sanded area. Salt water is more than enough to make corrosion over most steel compound in just 6 hours. Let it 24h and you will have perfectly differences from the not sanded nickel tinned part and from the sanded steel oxidation, and get absolutely nothing over a pure nickel sample. As the oxidation is formed inside a dissolution, most of the particles fall from the steel and stay sustained over its surface, so after washing with water, you will have just a visible darked area that also confirm that the surface is steel.

markz wrote:Did you put in the repository this DIY Tab Welder from this guy ?
Really interesting, just added, thanks for sharing.

vicens wrote:I'm looking at my bicycle wire.
I have my bicycle motor nc 9c. rated power 1000w. controller 48V 28A. I'm using 2.5mm2 cooper wire. equivalent to 10 AWG.
Am I using too thick wire?
According to the table. awg17 1.00mm2 wire. The maximum is 19A.
Would it be recommended to use this wire to a motor 350W, controller 36V 15A? The motor running at rated power output something like 36V 9.5/10A. It is half the maximum amps.
Is it better to use AWG 18.7 Limit 15A, to not waste copper?
Is it the same recommendation with nikel strips?

Did nobuo can add different measures that do not appear?
nikel strips of:
0.2x7
0.3x7
length is always a factor to take into account, AWG10 would be not far enough if your wires are 100 meters long :o The table takes into account standard dimensions for a nickel piece and for a battery standard wiring lengths (half a meter in the worst case). it is important to mark (as it is described) that those values are for an optimal efficiency, you could use double the amps indicated and just have your wires warm (never recommended) and rise over 3x the values to have smoke insulators. As greater the wiring diameter the better efficiency (less voltage sag) so never is a really waste, just stick to the recommended values. For a maximum 10A continuous output, AWG16 is more than enough for your battery leads.

I will update the table as soon as possible including further values, together with more visual tests.

joss wrote:I received some pure nickel strip in the post yesterday so I decided to do a short video showing the corrosion performance difference between this and the steel/nickel plated version I received a few weeks ago.

https://youtu.be/1r2tkwUnNv4

...now looking forward to putting my new battery pack together!
Thanks for sharing, I will add to the main page.

DVDRW wrote:Pure nickel strip seems pointless to me.
Nickel plated is 0.18mm thick
Pure nickel is 0.1mm thick and 2x more expensive
So current capability is about same?
You throw battery pack away anyway after few years when depleted before strip corrosion starts.
Current capability is around a 110% higher in pure nickel, average cost is around 80% higher. Spot welds are the first (and not visible) to start corrode, and "likely" happen with acid battery leads, corrosion forming over the conductor surface make a reduction conduction capability over the time, decreasing overall efficiency and safety. Nickel plated Steel is not a recommended material for spot welding. However, for specific dry environments, it could work acceptable using the right amount of layers.
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Post by douglashart » Feb 09 2016 3:41pm

douglashart wrote:nickel is nonferrous , thus non magnetic. Put a magnet to it, if its magnetic , its steel.
Sorry, I spoke , then , questioning myself, I did a bit of research and I was totally wrong. Just always assumed that I guess. Now today , a supplier informed me , that I was wrong also. So I figured I should negate my earlier statement.( Ill stick to questions from now on)

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Post by Punx0r » Feb 10 2016 3:36am

Don't worry about it - it's an easy mistake to make ;)

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Post by vicens » Feb 14 2016 8:15pm

vicens wrote:I'm looking at my bicycle wire.
I have my bicycle motor nc 9c. rated power 1000w. controller 48V 28A. I'm using 2.5mm2 cooper wire. equivalent to 10 AWG.
Am I using too thick wire?
According to the table. awg17 1.00mm2 wire. The maximum is 19A.
Would it be recommended to use this wire to a motor 350W, controller 36V 15A? The motor running at rated power output something like 36V 9.5/10A. It is half the maximum amps.
Is it better to use AWG 18.7 Limit 15A, to not waste copper?
Is it the same recommendation with nikel strips?

Did nobuo can add different measures that do not appear?
nikel strips of:
0.2x7
0.3x7
Nobuo wrote:length is always a factor to take into account, AWG10 would be not far enough if your wires are 100 meters long :o The table takes into account standard dimensions for a nickel piece and for a battery standard wiring lengths (half a meter in the worst case). it is important to mark (as it is described) that those values are for an optimal efficiency, you could use double the amps indicated and just have your wires warm (never recommended) and rise over 3x the values to have smoke insulators. As greater the wiring diameter the better efficiency (less voltage sag) so never is a really waste, just stick to the recommended values. For a maximum 10A continuous output, AWG16 is more than enough for your battery leads.

I will update the table as soon as possible including further values, together with more visual tests.
I did not understand the first page. It is unclear.
Nobuo wrote: Below the values ​​the nickel stays mild and close to ambience temperature, so the efficiency is optimal under current Those values ​​and you can measure the accuracy With Exclusively heat generated by the cells.
after that you can add:

You can use the values ​​in the table or less. for continuous discharge currents. If use twice the values ​​of the table. wires will be hot not recommend it and rise over 3x the values ​​to Have smoke insulators.
We recommend using cables with twice the constant current of the table. To reduce losses.

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Post by vicens » Feb 14 2016 8:44pm


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Post by Skrzypas » Feb 15 2016 3:09am

Has anyone welded 0.3 mm (x 7mm) nickel strips to the cells? My spot welder during welding with two handheld copper electrodes makes the nickel strip shine for about 1-2 sec and the strip does not weld strongly to the cell. It keeps itself, but can be removed with pliers moderately easy with no strip degradation.

So to decrease the temperature I had to cut the stripe into two 3.5 mm stripes, and put them parallely on the cell to make the welding current to flow through the cell terminal. It allows to work with much lower spot welding times. Similar approach is used by laptop battery manufacturers (they make a little groove between spot welding points).

Unfortunately the strength of spot welds on my case is not better than before either the shining effect was limited.

What can be the reason for that?

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Post by Offroader » Feb 15 2016 12:22pm

Skrzypas wrote:Has anyone welded 0.3 mm (x 7mm) nickel strips to the cells? My spot welder during welding with two handheld copper electrodes makes the nickel strip shine for about 1-2 sec and the strip does not weld strongly to the cell. It keeps itself, but can be removed with pliers moderately easy with no strip degradation.

So to decrease the temperature I had to cut the stripe into two 3.5 mm stripes, and put them parallely on the cell to make the welding current to flow through the cell terminal. It allows to work with much lower spot welding times. Similar approach is used by laptop battery manufacturers (they make a little groove between spot welding points).

Unfortunately the strength of spot welds on my case is not better than before either the shining effect was limited.

What can be the reason for that?
Really, so by cutting the strip in half it didn't make the welds stronger? I am going to weld .3 nickel and I have the JP welder, I do know that I have to really increase the amps to be able to weld it.

Are you pushing very lightly with the probes when welding? The lighter you push the stronger the weld.

What welder are you using?

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Post by Skrzypas » Feb 15 2016 1:35pm

Oh, I thought it's the other way around. I'll try to push lighter and post if it helped.

Cutting helped a bit but I can't get high quality connection yet. Maybe I need to practice few more hours...

My spot welder is a DIY microwave transformer-based type, connected to 230V outlet and controlled with a single step pulse with pulse duration regulation only.

It's strong, can melt the positive terminal on ca. 1s welding time.

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Post by Offroader » Feb 15 2016 4:50pm

Skrzypas wrote:Oh, I thought it's the other way around. I'll try to push lighter and post if it helped.

Cutting helped a bit but I can't get high quality connection yet. Maybe I need to practice few more hours...

My spot welder is a DIY microwave transformer-based type, connected to 230V outlet and controlled with a single step pulse with pulse duration regulation only.

It's strong, can melt the positive terminal on ca. 1s welding time.
Let me know how it works out, when I got my welder I was pushing hard and couldn't weld anything, so then I pushed even harder :D . I also thought the harder you push the stronger the weld. It is complete opposite and this factor made a huge difference in what I could weld.

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Post by joss » Feb 16 2016 1:28am

Thanks for the advice on how much pressure to exert - it makes perfect sense but I never thought to think about it (if you see what I mean)! :lol:

Now I don't need to break into a sweat pressing down with all my weight!!

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Post by Offroader » Feb 16 2016 3:14am

What happened with me is when I got my JP welder I was having a hard time welding .15 nickel. Sometimes the welds would be good and mostly bad, very inconsistent. Welding .2 nickel was almost impossible, but sometimes it would weld. Since I built the JP welder myself I thought I screwed something up.

By spending lots of time experimenting and with some luck I discovered that by pressing lightly the welds would be much better. I even tested it and by pushing hard .2 nickel would not weld at all, by pressing lightly it would weld solidly.

What I found odd is that I read over just about everything on this forum and nobody has ever discussed the importance of pressure.

However, I was pushing really hard with the probes and pushed even harder thinking it would weld better after I was not having any success. I guess most people just don't push that hard.

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Post by Nobuo » Feb 16 2016 6:43pm

Nickel, Nickel plated Steel and Copper maximum current chart is updated as requested.

Now I included the current levels up to the conductors can be pushed despite the optimal efficiency is not achieved.

Remember that for testing current capabilities on strip samples you need to insulate them first to get real-use values and temperature increases, also you should add to the equation that the conductors works together and in contact with cells that probably will rise its temperature, so you need to be more conservative with the real current capabilities, all are took into account in the chart
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Post by Skrzypas » Feb 17 2016 12:28am

Nobuo, change in the first post "all the values in the table" to some description of each column in the table, since now they're not anymore only optimum parameters but also risky stuff.

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Post by Punx0r » Feb 17 2016 4:35am

I am a little confused by those current ratings: on what length of conductor are they based?

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Post by up0 » Feb 17 2016 5:20am

> on what length of conductor are they based?

I would think that the length should not really matter:
If you push a certain Current (Ampere) through a wire it reaches the same temperature at every point, no matter how long or short.
e.g. check out this video https://www.youtube.com/watch?v=0DhzWPoSYoQ at 8:45 ;-)

Cheers, Ulli

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Post by Punx0r » Feb 17 2016 6:37am

So it is based only on temperature (will the strip melt through the battery heat-shrink)? I was thinking voltage drop would be the first problem.

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