Recommended · for some experience
Battery Spot Welder (CD Welder) || DIY or Buy
Why people recommend it
Referred to as a GreatScott build using a supercapacitor bank, useful for its energy working and for the mistakes it openly discusses.
Watch for: A supercapacitor bank can deliver very high currents that cause burns and sparks; learn from the errors covered rather than copying the build exactly.