Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!tut.cis.ohio-state.edu!tortoise.cis.ohio-state.edu!kronstad From: kronstad@tortoise.cis.ohio-state.edu (richard b kronstad) Newsgroups: sci.electronics Subject: Re: reviving nicads Message-ID: <85835@tut.cis.ohio-state.edu> Date: 10 Nov 90 20:22:36 GMT References: <1990Nov6.195112.11285@infonode.ingr.com> Sender: news@tut.cis.ohio-state.edu Reply-To: richard b kronstad Organization: Ohio State University Computer and Information Science Lines: 25 I have revived a couple of Nicads myself. basically you want to charge up a capacitor (try samller ones at first -1 uF) up to over 100 volts with a DC source. An AC source (such as a wall socket) will work as long as the capacitor is NOT ELECTROLYTIC (I blew a few up myself - nice blue glow) and the capacitor is rated WELL ABOVE 200 volts since you will cause a lot of current to flow - Come to think of it I DON"T RECOMMEND USING A WALL SOCKET! CHarge up the capacitor using a transformer and rectified at around 150 volts. Remove the capacitor (carefully - it could be a shoking experience if you touch the leads) and connect the diode "-" side to the Nicad "-" side and do the same with the "+" sides. You might see a spark, but that's allright because you want to spike the battery with an instant high current to break the crystals which cause a battery to die. The capacitor is necessary so that the total amount of electrons flowing is instantaneous and then nothing. I have noticed that is you have spiked a Nicad once or twice it should work again - not quite up to new capacity but it will work. Because the Nicad already had grown crystals spiking the Nicad will revive the batter but it is only a matter of time for the crystals to grow back causing the battery to die again. I hope this helped, I can't be responsible for your getting shocked but just be carefull not to touch anything high voltage - expecially the DC from a transformer!