I've finally managed to get everything together and start working on a small pack:
Everything is on a clear table - batteries + high power stuff don't go well with my cluttered bench
![kWeld - "Next level" DIY battery spot welder 900224-0](https://www.eevblog.com/forum/index.php?action=dlattach;topic=90086.0;attach=900226;image)
I've used 2 turnigy 3S 2200mAh cells in parallel.
They seem to stand the abuse - they are barely warm when the electrodes get unpleasantly hot 32 welds at 50J, with 1300A average
![kWeld - "Next level" DIY battery spot welder 900228-1](https://www.eevblog.com/forum/index.php?action=dlattach;topic=90086.0;attach=900230;image)
This is how a weld looks, on 5mm wide, 0.3mm thick nickel strip.
![kWeld - "Next level" DIY battery spot welder 900220-2](https://www.eevblog.com/forum/index.php?action=dlattach;topic=90086.0;attach=900222;image)
It seems a little bit to hot, but I've tested on some scrap cells and the weld is strong and the cells are not melted trough
And a microscope photo of another weld:
![kWeld - "Next level" DIY battery spot welder 900236-3](https://www.eevblog.com/forum/index.php?action=dlattach;topic=90086.0;attach=900238;image)
You can see the electrode angle and a little bit of metal flowing away (maybe add some flux - Rossman style)
(edit reason - I can't get the hang of this editor)