want to build said:
i do have a 48v 13s2p vtc4 cell.
IMO that pack isn't able to produce enough power to perform (satisfactory) welds.
And 48V is too high for spot welding. You really want something around 12V, give or take. Higher voltages are more likely to produce arcs and sparks.
As an example, my diy car battery powered welder is using a 750CCA battery (Arduino controlled with 16x low Rds mosfets), which probably puts out 1000A+ in short pulses (I have no way of actually measuring the current, but it gives you a ballpark). It produces
satisfactory welds, but would be better with more battery.
You
can weld with lower currents, but then you have to extend the weld duration, and you end up with poorer welds and hotter batteries.
If you configured your VTC4 pack into 4S6P, you could get nominal ~14.8V pack. VTC4 cell at 30A has about 0.7V sag.
https://endless-sphere.com/forums/viewtopic.php?t=96162 So your 4S6P at (only) 180A has 2.8V sag, giving you 14.8-2.8=12V nominal.
So that sag is at only 180A. Highly doubtful that you can get anywhere near 1000A to produce a good weld. Like I said, not enough power from the pack you have.
So IMO you really need a better power source to start with.
And finally, if you can't learn anything from all the great threads here on ES, such as the ones John linked to, then I honestly think that you're biting off more than you can chew.