The busbars which came with my 10 21700 cell Makita kit are just 0.2mm nickel plated steel.
They fail the spark test.
I got some 0.15mm nickel to be sure, which did not spark at all.
They just feel, and sound like steel when dropped on a surface, and feel way more magnetic than pure nickel.
Not going to bother with salt water rust test.
I tried to weld this on top of 0.3mm slot less copper stepping up the gear to 740, all other settings the same as post above
Not enough. Took considerable force to remove and then it popped off almost cleanly. two copper colored dots barely perceptible with a fingernail.
Gear 780 and one side tore the copper but the other side just a copper colored barely perceptible copper colored dot. So not enough.
The side which tore is not really big and wide enough that I would have much confidence in it, in an esk8 application, even if both welds were of equal size.
The tinning of the copper from the flux is almost a perfect 8, if both top and bottom of the number were equal sized
Stepped up to gear 830 and both welds same size and tore copper equally. Did not tear the NPS equally though. The copper is tinned in what looks almost like a perfect chain link around both welds. Very symmetrical.
I am not welding across a slot like I will be on Nelvick’s 0.3mm and the Kit’s 0.2mm NPS busbars when sandwiched, but it seems like:
AwithZ p20B
gear 830
Preheating 0.10ms
04ms intermittent ( pause between preheating pulse and first weld pulse)
double weld pulse
0.2 second interval between welding pulses, using flux, Is yielding Esk8 acceptable welds
on 0.3mm copper withg 0.2 nickel plated steel on top.
This is on the positive tab/ cathode of a Samsung 50E cell which has been welded to previously and had previous Nickel tabs dremelled off with diamond cut off wheel.
A cell which has had previous welds removed and the nickel plating removed always seems easier to get a weld to stick, as long as both strip and cell are flat.
Thicknesses of previous welds, unless removed so strips can sit flat, changes the dynamics and adds too many variables in my opinion.
Gear 830 is a lot of power, the weld leads really jump, an I keep them close to each other but not attached. I try and hold the weld pen bodies more like an H rather than a V, as I feel I can more evenly exert the same pressure on both electrodes, and have their rounded tips be more the same shape pressing the sandwich to the cell and increase consistency and repeatability.
The reason I am considering using the kits NPS busbars on top of the Copper busbars is for simplicity. I can cut off the balance tab reaching for PCB BMS and easily weld sandwich together, then place them on the 4 flux’d cells and turn gear back up to 830
I do have Slotted 0.1mm stainless slotted circles I can position on each cell too, but these are a little bit big for the cathodes, and the slot is not lining up perfectly, causing the outer edge to catch on the cell holder body.
I’d rather use a lower gear(615) and the 0.1mm stainless opposed to gear 830 and 0.2mm NPS, but the latter will save a lot of time, and I have no other use for the Kit’s busbars.
The 0.2NPS will add a smidge more ampacity but it is 0.3mm copper below it.
If I were an electron I know which path I’d choose.
I wound up dremelling some slots in both 0.2NPS and 0.3 copper, and used gear 830, and welded to the 50C can, and Ieft symmetrical copper dots on the cell, but one side was tinned more so than the other side, but this could have been unequal amounts of flux on either side, since the flux can squeeze out the slot and not spread evenly.
Again, I am becoming less and less of a fan of the slot, for either sandwich alignment purposes, or for lessening welder power required.
Welding onto cells previously welded to, and dremelled free of those welds is also another variable as there is no way the scratches left on the cell and the thickness of remaining nickel outside those dremmeled areas will never be the same.
err on the side of power. it seems can puncturing is unlikely if one is using 10% more power than technically required to achieve minimum esk8 welds.
So it comes down to is this higher power level going to negatively affect cell longevity and performance in any meaningful way?
It will affect welder longevity, but again, in any serious way?
I don’t know.
