@taz That’s the theory. kWeld calibrates system resistance when you set up, and actually measures the energy going into each weld. I think it’s a little flawed, as it’s energy over time that makes the heat, right? But it’s still doing a lot more than just timing.
kWeld is also built quite tough by design and testing. Hard to kill. Everything (probes, wires, battery pack) gets hot before the welder.
Some notes I have for weld energy using HK Graphene 3s 6000mAh 65C:
official chart
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0.1mm 20j
0.2mm 50j
0.3mm 100j
deucesdown testing with utility knife blades and dirty used cells
1 x 0.20mm nickel to steel: 20-35 joules (35 gets hot)
2 x 0.20mm to blade:
45j sticks okay
50j very good stick, hot
55j very good stick very hot
1 x 0.25mm 20-40j
1 x 0.30mm 70-120j (120j was best, but 100j+ was HOT)
@tatus1969 thanks for joining here. Really enjoyed the thread as it was going on ES. Since you’re here I’ll throw you right into the fire. 
I know on ES you’d helped revive some early kWelds that broke, so was surprised to read this. Can you shed any light?
@magharees thanks for making the thread and badgering the maker to come over. Maybe add “Next Level Spot Welder” to the title? That name has been used in a few places, and adding it to the title or first post might help reduce confusion.
EDIT size comparison kWeld vs Boss
