18650 spot welding -how to- ULTIMATE REPOSITORY

meelis11 said:

Punx0r said:

Try a Type B circuit breaker - these are used for devices with large inrush currents (motors, transformers) to prevent nuisance tripping.

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I had also similar problem - when turned welder on then breaker tripped. Connected welder to kitchen socket where normally electric oven is connected and no problem anymore, even when using 5m extension cord.

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The inrush current is probably larger than the (i think) type B breaker allows. From what I've read, type A isn't used in home installations because it trips very very quickly.
I will try a type C or check which group this already has when I get home after work. (I don't have a 30A group)

Thanks for the information. I will post the results.

Apologies, you are quite correct, normal fitment is a type B and going to a type C would approximately double the surge it will tolerate before tripping,

This is the beauty of the JP welder. No electrical problems or adventures. Not to mention an actual warranty and the ability to have the welder repaired. I have a Sunkko 709A with a spare PCB that is useless. $250 in junk that would cost near that to have professionally repaired.

I'm wanting to build a 20s 8p pack. The pack will be 5 cells wide and 16 long, 2 layers.

What would be the best way to series and parallel this pack and also how to connect the balance wires. The ballance wires will need to be in 4s so I can plug into the adaptto BMS.

Any help would be appreciated. I'm a nobb when it comes to battery building.

Hi all
Ridethelightning and I have been figuring out some stuff... Specifically how to weld copper. It's difficult on my MOT welder ( which does .2 nickel with ease) but not impossible. Consistency is the issue for every weld. The benefits of copper are that its cheaper (1/4cost of nickel) and it carries 4x the current. So it's worth pursuing, especially when you need the amps RTL does!
What we've found with copper...
: 0.1mm copper is the upper limit for thickness to do easily, above this causes to much heating of the cell. a better spot welder (remember I'm using a MOT style) might be able to do it. (JP users comments welcome)
: nickel plating is easy to do at home ( like making a milo according to RTL!)and makes it easier to weld, the main benefit is stopping the work piece sticking to the electrodes.
: it must be slotted-10mm seems to be the minimum I can do from an end, but requires more if it's a middle slot( like 15mm)
: I'm using copper electrodes- light pressure works better. It increases the resistance of the joint resulting in more heating locally and less total current flow( judging by the noise/heating/MOT recoil) The draw back is if it's too light it can arc, blowing a hole I your tab (or even battery )
: clean and smooth surfaces are a must.

The draw backs are:
:It's fickle and results in a poor weld if not done carefully each time= slow going
: .1mm copper is not very strong, it's quite easy to rip the tab off even with a good weld.
: it can cause more heating to the cell. more current is used but the copper can conduct it away resulting in a larger heat affected area
:the electrodes sticking is a PITA requiring a light sand every 4-5th weld othwise it arcs. If it arcs I have to file the electrode surface back to smooth again.
Really like to hear from others who've had a go at this, and any handy tips.
I'm very close to being good enough to use copper on my good cell but not quite there yet...
Kdog

hello folks...just thought I would share my 0.2 cents on this forum. I have received enormous amout of help from this forum, so thought would share what worked for me.

I was successfully able to build a 4P10S pack using a cheap generic 110V weld off ebay. The only caveat of of this spot welder is that it is not powerful enough to weld 0.15 mm nickel plate, but it does a great job with 0.1 mm thick nickel plates. It can weld the 0.1 mm nickel plate so hard that you have to pry it off with a plier, and it will still leave enough residue which will require a dremel tool to grind it off. To make sure that these nickel plates can handle enough current, I made sure to layer two layers of 0.1 mm nickel, and topped it off another 1.5 mm nickel strip, just to be sure. It's a bit of work, but works like a charm.

I used the following tools (straight off ebay, mostly):

110v Spot Welder: http://www.ebay.com/itm/Hand-held-Spot-Welder-Machine-Welding-for-Mobile-phone-Battery-Pack-110V-/230919460933?hash=item35c3df5845
8mm x 0.1 mm Nickel Strip: http://www.ebay.com/itm/141684489923?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT
Battery Level indicator: http://www.ebay.com/itm/121672359374?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT
CellLog 8M: http://www.progressiverc.com/celllog-8m.html
Samsung 25R https://www.fasttech.com/p/2706600
22 AWG balance Leads: http://www.ebay.com/itm/371251803318?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT
12 gauge silicone wires : http://lunacycle.com/batteries/wires/12-gauge-silicone-insulated-wire-per-meter/
Kapton Tape: http://www.ebay.com/itm/US-Shipping-BGA-High-Temperature-Heat-Resistant-Kapton-Tape-50mm-X-100ft-/181490629891?hash=item2a41af3d03

And, for the Battery case, i used the following materials:
Impact Resistant Flexible Plastic: http://www.ebay.com/itm/271911537961?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT
1/4" Hi Density Upholstery Foam: http://www.ebay.com/itm/1-4-x-15-x-60-Hi-Dense-CLOSED-CELL-Uphol-Foam-G-/201413910872?
1.5" Duct tape: http://www.ebay.com/itm/3M-Scotch-1-5-x-5YD-Brown-Multi-Purpose-Duct-Tape-1005-BRN-IP-/141771239475?hash=item2102397033

And here are the results: It works like a charm. I couldn't be happier.

Cheers.

Hey sonnetg
Did you try slotting your nickel? It makes a big difference. You might find you can do .15mm even at modest power levels. But you've already made your pack.. Maybe next battery- cause there will always be a next!
K

It's really sad that these welders can't weld even 0.15 mm nickel.

Yeh I was suprised to hear that. Glad I built my own, but I was vaguely thinking of getting one for a while.
Btw riba, have you tried welding copper with your welder? Heard of anyone else using yours to do it?
K

riba2233 said:

It's really sad that these welders can't weld even 0.15 mm nickel.

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At least my 788 spotwelder welds fine with 0.15mm nickel strip, cannot comment other welders

my feeling is that they will definately be able to weld copper with such a short weld pulse and potentially very high current with lots of car batts in paralelle.

the key to making it a smooth job i think is a tungsten tipped electrode. this will not melt like a copper one or stick to the tab. it will also create the resistence needed to create the heat for the weld, at the tip, similar to the effect kdog saw when only using light presseure with his copper electrodes....though...kdog knows all of this, hell, i banged on about it multiple times in a fever of excitement from seeing the copper tab actually welded properly with his MOT welder

riba2233 said:

It's really sad that these welders can't weld even 0.15 mm nickel.

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True, sad indeed, if think all the DIY microwave welders running on the same 110v/15A outlets. That being said, you actually can weld 0.15 mm, but I didn't feel secure enough as it was easy to pry off so I layered the 0.15mm on top of two 0.1 mm nickel strips on the parallel junctions. Seems like the spot welder i used was made more for cell phones or small applications. I don't have a 220v outlet in my condo. I might eventually get the JP weld, but this welder works with some work around. As long as the battery holders are secure, I dont really anticipate any issues with the weld.

Time will tell how my build holds up to abuse though. That's one reason i took the duct tape route. It's easy to dissemble and inspect.

kdog said:

Hey sonnetg
Did you try slotting your nickel? It makes a big difference. You might find you can do .15mm even at modest power levels. But you've already made your pack.. Maybe next battery- cause there will always be a next!
K

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By the way, i am not familiar with "slotting"? What is this process? Maybe i need to read up a bit more. I actually found this link very helpful for my build:

http://www.ebikeschool.com/how-to-build-a-diy-electric-bicycle-lithium-battery-from-18650-cells/

You bet there will be more builds. This was only a warm up. The other draw back was the lack of remote "pen" hand held electrodes. With the fixed electrodes mounted on the welder, you are only limited to maximum 4P configuration. Now that I have the time, I will shop around for a better solution. The 788 battery spot welder would have been my preferred, but I dont have any 220v outlets at my condo. The next coice would definitely be JP welders. I was amazed by some of the video demonstration of the JP weld. Hats off to Riba for his ingenuity

Thanks

Yeah, my welder can weld 0.1 mm copper without any problem, it can even blow it solid but I don't like welding it, it is less consistent than nickel and it is fragile after welding. Maybe someone should try 0.15.

@sonnetg
Slotting is the process of cutting a small longitudinal slit in the middle of the tab right where you want to weld. The electrodes bridge each side forcing more current to flow down through the nickel into the battery and then back up to the other electrode cause around the slot is much further. . It makes for a much easier weld. Check out any commercially available tabs all the little slots are for this purpose.
Try it on .15 and I reckon you'll be fine.
K

kdog said:

@sonnetg
Slotting is the process of cutting a small longitudinal slit in the middle of the tab right where you want to weld. The electrodes bridge each side forcing more current to flow down through the nickel into the battery and then back up to the other electrode cause around the slot is much further. . It makes for a much easier weld. Check out any commercially available tabs all the little slots are for this purpose.
Try it on .15 and I reckon you'll be fine.
K

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Wow. I always wondered why many commercial nickle plates had those slits in the middle. I suppose it's amazing science at work. I have to give that a try. Thank you for this valuable piece of info.

By the way...am i the first one on this forum to successfully try out a 110 volt spot welder

Has anyone else had luck with these low powered spot welders? I am happy because I never expected it would work. I was pretty sure it would break down in the middle or blow a fuse or two, but it survived. I was concerned about heat buildup on the strips due to current draw, but it works fine with my 350 watt hub motor. I think my controller is rated for 10A continuous. Can't speak for anything higher powered.

Also, one thing i need to point out, the plates i used were not pure nickel. I did a salt-water test, and it started to rust the next day. I believe steel allows for more current draw, so I left it there. And I did not have the patience to wait for another shipment from china. I haven't done any resistance test or anything, but I am happy I get about 25 miles on a 11.6A pack with pedaling. I am ok with this welder. But for future and larger projects, I need to procure something more powerful and consistent in weld quality, which this welder is definitely not.

Unfortunately nickel plated steel has 2x resistance of nickel... So half current carrying capacity. However for your low amp draw and triple layer tabs! I think you'll be fine. I saw 4x parallel strips on your series connections so that should cover it.
I checked out you link to the capacity meter and bought two so cheers. Can't believe they were only ~$5

looking at the pack i cant figure out how it's 4s10p

the 10p cells are not connected together. looks like 10s4p to me.

clockwork247 said:

looking at the pack i cant figure out how it's 4s10p

the 10p cells are not connected together. looks like 10s4p to me.

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My bad...i didn't even notice You are absolutely correct. Thanks for catching this. I have fixed it now.

sonnetg said:

clockwork247 said:

looking at the pack i cant figure out how it's 4s10p

the 10p cells are not connected together. looks like 10s4p to me.

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My bad...i didn't even notice You are absolutely correct. Thanks for catching this. I have fixed it now.

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np. i thought i was going crazy there for a sec . you did a great job. it came out very nice.

clockwork247 said:

np. i thought i was going crazy there for a sec . you did a great job. it came out very nice.

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Thank you. Yeah...got a bit carried away you could say... (the reality was all the decals and stickers do an excellent job hiding a shoddy craft work..but who cares..it works)

I can buy one SUNKKO 788+ and add about welding pen?
Connect as in the picture?
I want to make a battery packs 9x10 18650

http://es.aliexpress.com/store/prod..._73_74_75,searchweb201527_2,searchweb201560_9

I love this thread... So I'll post some results of some nickel strip testing I've done. Before you all get too excited this is rather rudimentary at this stage cause I don't have a IR gun.... So it's up to the ol' finger test :?
I wanted to see what heating was caused by current in a .2mmx8mmx100mm nickel strip.
Temp in my shed aprox 30deg C and I ran set current for a minute or so with the strip completely wrapped in my fingers to simulate thermal insulation.
Calculated amp carrying capacity should be .2x8x19/4= 7.6amps before warming occurs
Results are as follows.
<5A no perceptible heating
7A barely noticeable heating ( right on calc value)
10A slightly warm
12-15 warm- quite warm
After this heat production went up markedly...
16A really warm/hot
17A very hot
18A couldn't hold it for the minute
I think 10-12 amps continuous would be max acceptable (for me) in a battery I owned. In my mind, I have revised my peak vs continuous capacity. I expected more linear heating, and I'll remember that even small peaks caused rapid heating.
If I find an IR gun to borrow I'll get a bit more accurate.
It seems nobuo's table on the first page is accurate in this one off test but the values can be pushed a bit, depending on your thermal situation etc.
k

Re tested at cooler temps (15c) seems I can probly get up to 2-4 more amps out of this strip.
Still you want to work on worst case scenario so I wouldn't recommend it.
the SA of this strip is high compared to a round wire of comparative volume, so i guess that is an unrealistic advantage in cooler temps.
The insulation on the connecting 20gauge wire (.8mm)was starting to liquify at 18 amps (at the alligator clips) whilst the strip was hot but not uncomfortable ( not that I'd want this inside my pack)
Anyway it's interesting
K
(The good news for myself and RTL is that 18amp through .1x8mm copper caused only very mild heating- prob comparable to about 8-10amps in the .2 nickel)

K
(The good news for myself and RTL is that 18amp through .1x8mm copper caused only very mild heating- prob comparable to about 8-10amps in the .2 nickel)[/quote]
so 0.1x80mm should be good for ~ 180A