Is it possible to just cut the Ss portion off and solder to the copper?
sure.
But I do not have those fancy round slotted SS pieces (where to get those?). For now I use SS strips to sandwich. From there it is easiest to have longer SS strip protrude the underlying copper and use this end of SS strip for connecting the balance wire to.
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Nelvick hooked me up with those laser cut slotted SS circles.
I have gotten decent at cutting circles with tin snips but laser cutting just looks soothing.
@A-damW has successfully soldered to stainless, IIRC.
I tried once and saw it was so solderphobic I wrote the possibility off, and welded pure nickel to the stainless and soldered to that.
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Hi guys,
IĀ“m flying RC and using LiIon cells since around 1,5 years so far. Nelvick gave me the tip to this thread. Yesterday I started testing my AwithZ P60F with Nelvicks parameters of his YouTube video for 0,4mm Cu and 0,1mm SS + Cu Flux. Used also 0,2mm SS later. With 900 gear the first weld was more like an explosion (discharged old light 1200mAh 18650 cell of an RC car). Went down to 500 gear but in did not hold on. 700 gear was good but still my pens did stick a bit to the copper or SS and have a lot of wear. Sometimes there are āphenomenalā sparks, sometimes not. I think it depends on the contact to the cell? And I also suppose the SS sheet should not have holes (seeing the copper) after welding? The cell got quite warm after one welding and more after two.Tried also 0,6mm copper with 0,1 SS and Flux on gear 900 but it did not work.
Copper (with 0,1mm SS) āsticksā quite well on 710 gear, preheating 0,10ms, intermittent 02ms, trigger time 1,6s and 2 continous spot welds.
I took a lot of pictures. Here you can see 0,4 Cu with 0,2 SS above and 0,4+0,1 welded to the cell (beneath). Both with flux and the settings described above. I had the feeling that 0,1SS made a stronger bond but both were firmly attached. On the last weld on the top of the cell I made a hole on the side of the top pole into the cell. I suppose it was a contact issue but it would have been desastrous with charged powerful cellsā¦ Also this small 18650 are quite small for a newbie. Bad news because I wand to build a lot of packs with 30PLsā¦
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I couldnĀ“t upload picturesā¦ I opened a thread on DIY500AMP Fb pageā¦
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As a new member you are not allowed to post pictures until you do a certain amount of reading and such to prove you are not a bot or somone just selling something.
If your test 18650 is pretty old no name cell, blowing a hole in it is not necessarily mean that all 18650s are in danger of the same. I had some āwintonicā 18650 cells from a laptop battery which punctured quite easily, as it seems the can was thinner steel.
Sparks Flying is pretty normal, and sometimes the amount of sparks varies despite all the other variables seemingly being the same.
But downward pressure on the welding pens is always a human variable, and hard to quantify how much downward pressure one needs to use, between different users.
I have no experience trying to weld homogenous copper thicker than 0.3mm, under 0.1mm stainless steel, and I only have the P20b welder.
it does not matter so much on test cells but you dont want to use too much flux on the positive tab to where it can squeeze out and get under the ābridgeā supports and potentially bridge + and -.
Keeping the tips clean, and keeping them the same conical shape, holding them at the same angle and the same pressure each time you weld will allow you to refine your methods and the settings required for the material thickness you are welding.
I try and hold my welding pens as close to an H shape as possible rather than a V as I believe it helps ME be more consistent in downward pressure and have the tips shape contact the sandwich be more consistent, and also the same distance apart.
The Distance between the probes is also another variable that one should seek to reduce as much as possible. The wider one holds the tips away from each other the more that the surrounding copper and steel dissipates the welder power, so if you hold the pens 7.25mm apart, try and remain consistent in this distance to get more consistent welds.
Also high power levels are going to wear out the tips faster and you will need to clean and shape them more often.
i feel the little red file provided with the welder is too aggressive, and will actually leave sharp mountains and valleys in the tip, reducing the contact surface area, making it hotter and being different than subsequent welds. I have taken to using an Arkansas sharpening stone which is likely somewhere in the 800 grit sandpaper range to clean and shape my tips.
Also when you see copper through the SS after a weld, it could be copper left behind from the welder tips, not necessarily a hole blown through the stainless.
Do some more thread reading and contributing and click any number on the top right and you will be able to post pictures relatively soon. I cannot and will not do anything facebook, and missing out on Nelvickās page there does give me some FOMO, but F Zuckerberg.
Look forward to seeing your pictures
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I found that welding anything over 0.3mm copper, thicker SS 0.2 works better than 0.1mm SS.
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I have attempted to weld 0.25mm copper, under 0.1mm stainless steel, without flux, and set my AwZ p20B welder as high as Gear 930, 0.15ms preheat, 02ms intermittent, triple pulse with a 0.2 interval between weld pulses.
Rolling this combo off of a Samsung 50E can was deforming the can, but it did Not leave torn copper on the cell. There was some copper left on it. Enough that flush cut nippers were able to get it and shoot it across the room. It did take a lot of force.
It Did not feel like it hit hard enough to actually weld it, so I was surprised it was stuck so hard and deformed the can. Also, one weld was stronger than the other which I feel is another indicator that more power is needed. Would gear 990 do it? maybe.
Would this be strong enough of a weld for Non Esk8 applications. I believe so.
Will I max out the power of my machine every weld to forgo the flux in order to weld 0.25mm copper under 0.1mm stainless? No.
So I busted out the flux and went back to double pulse and down to gear 650. Not enough.
Gear 699. One great weld, one kind of weak, similar to the fluxless gear 930 welds.
Gear 739 two equal great welds on a JP40 can.
The stainless shears off when rolling the sandwich off, but both holes of the sheared SS are the same size.
I had expected a lesser gear to be able to weld this 0.25cu/0.1sssandwich with flux, as with 0.2mm copper under 0.1mm stainless steel with out flux requires gear 550, and with flux requires gear 385.
So if āgearā is linear to actual power, then going from 0.2cu/0.1mmSS sandwich with flux to 0.25mm cu/0.1mmSS with flux, requires nearly double the welder power.
I had not welded anything for a while, but was kind of surprised at how I could just tell if a weld was close to the right range, by how hard the table shook when the pulses of current hit.
My very first weld tonight, I tried to weld 0.25mm copper, no flux and no sandwich, at gear 930 and had to doublecheck after the weld to make sure I had not passed the 9 back to 0. There was no violence when those gear 930 double pulses hit, but that piece of copper, which popped off with the lightest effort, was certainly Hot AF.
I have just less than a Meter of 10 CM wide 0.25mm copper sheet, and Am Ok with using ~3/4 the P20b welderās power, with flux, to be able to weld it to Esk8 standards.
I do better understand the reluctance to use flux, but with 0.25mm copper and this P20B welder, it seems it is necessary. I donāt want to have to max out the welder each weld and be right on the edge of an esk8 acceptable weld, even in non esk8 applications.
I have some 10mm wide 0.15 and 0.2mm copper rolls, but I find myself wanting to cut 33x30mm squares and bending the extra over the insulated shoulders even in a non flex non esk8 battery that will never ever require 0.25mm thick 30+mm wide copper busbars.
But, I like 0.25mm copper, and I like stainless, and I have both, and I can weld them, and that gives me the warm and fuzzies.
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Have you tried 0.15mm stainless with flux on the 0.25 copper? Wouldnāt that increase resistance a bit concentrating the heat in the spots. seeing that your 0.20 copper with 0.10 stainless decrease your Gears settings 550 to 385. and I read something that the stainless thickness should be half of the copper thickness. The jump in Gears from 385 to 739 for just and additional 0.05mm of copper seams quite large that is why I am asking if the additional thickness of stainless might be what the doctor order yes? I am just spit balling here as I am new to this and only asking based on what I read on the forum. I am very interested as I need to buy supplies and do not know if I should buy 0.2 or 0.25 copper for my builds. I will be running current so the thicker the better for all the advantages it gives
with a P20B welding 0.25copper with flux should you use 0.15 or 0.10 stainless?
Also is there a difference using 301 or 304 stainless steel?
I have not tried 0.15mm stainless.
I have tried 0.07mm stainless that advertised being 304, and could not tell much if any difference between that and 0.1mm stainless, on 0.2mm copper.
The 0.07mm stainless I bought reacts to a magnet differently than 0.10mm 304, and I donāt think the 0.03mm is to blame.
More than Willing to try 0.15mm stainless, I too have read that the SS should be half the thickness of the copper under it. Makes sense.