I heard about this on a welding forum. Battery packs from cordless power tools can be zapped back to life with a DC welder. Ever the sceptic, I thought yeah sure, another Internet legend with no truth behind it, but there were enough guys claiming it worked and what the heck, I had nothing to lose. I have a DeWalt 14.4 v cordless drill and driver with 3 dead defunct batteries that would not take a charge. The theory is something about "dendritic failure" or sump'n where these micro chrystaline dendrites or bridges form internally and eventually they short out and a blast of amps from a DC welder supposedly fries these dendrites and restores the battery at least partially.
My wife begged me not to try it, said I would blow myself up or something worse (huh?) so I decided to try it. I cranked up my Miller arc welder to about 90 amps and hooked up a set of battery jumper cables to the posts on a battery pack. Neg welder to neg battery post and put a stub electrode in the stinger from positive, donned my sexy speedglass helmet and "popped" the rod on the positive side 3 times. I'll be darned, it worked. All 3 batteries were able to be charged but one went back to fault mode before fully charging. The other 2 are working fine! For how long I don't know but hey, it's more than I had! I might zap the other one again or just get rid of it if it doesn't take but I thought some of you might have a dead cordless NiCad sitting around and want to try it. I used needle nose vice grips to the battery posts and clamped onto them. The 6g jumper cables got me 10 feet away from the battery but nothing bad happened.
My wife begged me not to try it, said I would blow myself up or something worse (huh?) so I decided to try it. I cranked up my Miller arc welder to about 90 amps and hooked up a set of battery jumper cables to the posts on a battery pack. Neg welder to neg battery post and put a stub electrode in the stinger from positive, donned my sexy speedglass helmet and "popped" the rod on the positive side 3 times. I'll be darned, it worked. All 3 batteries were able to be charged but one went back to fault mode before fully charging. The other 2 are working fine! For how long I don't know but hey, it's more than I had! I might zap the other one again or just get rid of it if it doesn't take but I thought some of you might have a dead cordless NiCad sitting around and want to try it. I used needle nose vice grips to the battery posts and clamped onto them. The 6g jumper cables got me 10 feet away from the battery but nothing bad happened.
