Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10 5/3/83; site umcp-cs.UUCP Path: utzoo!linus!philabs!seismo!rlgvax!cvl!umcp-cs!fred From: fred@umcp-cs.UUCP Newsgroups: net.auto,net.rec.boat Subject: Re: Marine batteries Message-ID: <1361@umcp-cs.UUCP> Date: Mon, 1-Aug-83 19:59:58 EDT Article-I.D.: umcp-cs.1361 Posted: Mon Aug 1 19:59:58 1983 Date-Received: Wed, 3-Aug-83 03:45:51 EDT References: <339@hou5f.UUCP>, <2065@alice.UUCP> Organization: Univ. of Maryland, Computer Science Dept. Lines: 24 From: wookie@alice.UUCP Ni-cads . . . tend to crystalize if left on the charger all the time and will not work at all unless you zap them with a very high current for a short period of time (seconds) to break down the crystals. WARNING: This is a dangerous practice as the battery can explode throwing potassium hydroxide all over the place! Keith Bauer White Tiger Racing I once sucessfully revived my rechargeable ni-cad electronic flash unit by doing just this. I used a small capacitor (about 30 mfd.), charged it from the flash unit's recharger, then touched it to the terminals of the flash unit, but with the polarity reversed. It's now accepting a full charge, just like new. I imagine that doing this with a much larger battery could well be dangerous, but there doesn't seem to be much danger with the small (C-cell size) batteries in a portable flash unit. Besides: no one warned me. I suppose that another safety factor is that the total charge in the capacitor is extremely limited, so the reverse current will only flow for a fraction of a second, not long enough to cause an explosion.