Mini Spot Welder - watch/modify before use it

How to fix the mini spot welder before using it
to avoid its destructions.
The welder has a faults on its project, and it could self damage with weak batteries

UPDATE 20/03/2021
I measured the current pulse of the welder, which is aprox 900A, thats why a voltage drop is easy to happen.
See details on video:
https://youtu.be/XaHymCqv64E

UPDATE 30/03/2021:
ABOUT NEW VERSION PCB (B11-1k)
Luca Forattininshpuld have fixed all the versions:

https://youtu.be/RSrlXqFxhp8

I cannot verify because i don t have the second pcb version
ABOUT THIS VIDEO FIX:
The mosfet control circuit does not have a protection, but with a simple mod you can make it safe.

All you need is a 1000uF 16V(or higher) capacitor

The battery voltage should not drop too much if the battery is properly sized and charged.

But you never know, weak connector, discharged battery, low c rate... and you explode your welder

I would modify it before using it

In case you destroy the mosfets like me:

I replace the 5 broken MOS with 4 superpowerfull Infineon MOSFET:
IRL40SC228CT 0,5mOhm 1440A pulsed

https://www.digikey.com/en/products/detail/infineon-technologies/IRL40SC228/6834099?s=N4IgTCBcDaIJICUAyAWADAZQMJjADhAF0BfIA

Intro: (0:00)
TestWithOscilloscope:(1:46)
Modification:(3:33)

Видео Mini Spot Welder - watch/modify before use it канала Maker Fabio