Making a capacitive discharge spot welder is a little more challenging than I had anticipated.
For the longest time I've wanted to build a capacitive discharge spot welder for battery tabs. One problem being is that I couldn't afford or find suitable capacitors. Building one with new capacitors costs way more than I'm willing to pay for what in reality is just an experiment. So you can imagine my joy when I got a whole box of capacitor banks completely for free! Yes, whole capacitor banks. These come from forklift motor drivers that blow up beyond repair. The drives that these banks came from have their capacitors on a separate board, making it super easy to pull them out and use on something else. These banks consist of 30 electrolytic capacitors that are rated for 63V and 680µF each and are all connected in parallel in a large capacitor bank. Each bank has two plates bolted to it that each serve as output terminals and have aluminum blocks on them with M8 tapped holes, ready to bolt to. In total this comes to just over 20mF of capacitance and at 60V it would hold ...