Modifiying the Sunkko 737G and building a battery pack (welding pen mod)

so i got myself a battery spot welder. the sunkko 737G
it worked well in its delivered form but i needed to use an external pen type setup.
so here is my go at modifying it and in the end i have a useful setup.
In the next video ill be doing further mods to finalize the machine

[@jehu2134]

What AWG is it ?