At a glance we can see the major components you’d expect in a discharger: a fairly simple PCB, four ceramic power resistors, a holder for a single 18650 ... device a battery charger, [Jasper ...

You can salvage lithium 18650 cells from all sorts of modern gadgets, from disposable vapes to cordless power tools. The tricky part, other than physically liberating them from whatever they are ...