There’s a terrific instructable movie about the best way best to zap Ni-Cd batteries using a welder and deliver them back to life. Regrettably, that movie doesn’t cover memory problems using Ni-CD batteries, welder configurations, which control your welder earth versus optimistic is, and the number of times is suitable for zapping. This movie helps with these difficulties. Make certain to only attempt to zap cordless power tools which are Ni-Cd based. The more recent programs are Ni-MH and Lithium based. Do not zap those.