I did really need a spot welder though, and there was no shortage ... As the supercapacitors were roughly the shape of a large battery, I put a collar around one electrode as a spacer.

That need is what led [Erwin Ried] to purchase a small, battery-powered spot welder from a maker in Korea ... and is designed to be portable and powered by batteries commonly used for RC.

This rechargeable battery-powered welder provides up to 180 amps of welding power (True DC Power). Quiet with no exhaust fumes, making it suited for indoor use Lightweight, portable and compact at ...

a self-contained battery-powered MIG welding package and the first professional system for true "off-the-grid" welding. The portable (52-lb.) Trek delivers heavy-duty weld power to fabricate or ...