So we know that people usually do 4 or 6 spots.
How many amps is 1 spot? I always thought 5 amps so if I’m pulling 30a from a cell, I do 6 spots. 3 clicks with my welder.
Does it matter if it’s nickel or copper nickel sandwhich?
If it’s too much to figure out, what’s the worst case? 5 amps per spot? 3amps?
Reason I’m asking is because I did 6 spots on my cells. I can pull 300a but my wires can only do 200a. If that’s the case, I’ll just replace or double my wires and start pulling 300a.
Most people go by 5amps per spot being a rule of thumb…
No idea if there is any science behind that number, but that’s the general consensus.
I see. Ok. Thank you.
onewheel people with their 32S1P battery packs 
The 5A per point number comes from some measurements about the diameter of a weld but it only applies on a good weld, a more reasonable number is 4A per negative side weld and 6A per positive because the extra thermal mass means negative end welds have a bigger heat affected zone but smaller region of diffusion
I just decided to go with 5A because 4A-6A is 5A. LOL.
Sometimes going 8 spots per side because P45B. LOL.
But I’m guessing it also changes with the material. Copper/Nickel Sandwich, I’m guessing would be able to handle more? Just to be on the safe side, I’ll say 7A per spot for copper.
Would it still be about 5A if it was copper nickel?
I think there is a lot of variability in how much each weld can carry.
The surface area of the welded area depends on the size of the electrode tips, their shape and the angle they were held during the weld, and.probably the amount of pressure used as well.
One other variable is how much of the copper/nickel strip outside the welded area is still in contact with the cell after the weld.
I had some comically thick 0.5mm stainless steel on hand when testing a new welder and welded it atop some copper. Just one weld, two dots.
The force required to tear off the strip was extreme, and the copper remaining on the cell was wide and flat adjacent to the weld.
If the goal is simply to have as much copper strip in contact with the cell as possible, the comically thick stainless pressing the copper flat with only one pair of welds, two dots seemed to work extremely well.
But actual testing would be required to definitively say, and i have no data.
But if one 0.2mm nickel strip welded to a cell is considered good for 5 amps per welded dot, I’d expect pure copper is 20 amps.
But again, no data.
The limit is defined by heat and heat takes time to build up. So it’s about how long you pull that amperage for.
That 0.5mm stainless steel experiment sounds very intriguing for sure
