Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!bloom-beacon!mit-eddie!ll-xn!vlsi!malpass
From: malpass@vlsi.ll.mit.edu (Don Malpass)
Newsgroups: comp.sys.ibm.pc
Subject: Re: Overcharging NiCad batteries?
Keywords: NiCad rechargeable batteries, laptops
Message-ID: <175@vlsi.ll.mit.edu>
Date: 26 Sep 88 15:13:10 GMT
References: <3008@dalcs.UUCP> <14705@agate.BERKELEY.EDU>
Reply-To: malpass@ll-vlsi.arpa.UUCP (Don Malpass)
Distribution: na
Organization: MIT Lincoln Laboratory, Lexington MA
Lines: 14

In article <14705@agate.BERKELEY.EDU> koonce@math.berkeley.edu (tim koonce) writes:
>Odd trivia:  Several people I know have successfully restored ``bad''
>NiCads by putting a high charging voltage (24 volts or higher across
>a 1.5 volt cell) on them for a short while.  This seems to burn out
>small bridges that form internally after a while.
>
A safer trick is to charge up a BIG capacitor to some large voltage and
then use clipleads to zap the nicad with it.  It'll give an
instantaneous current spike that burns out the short, but won't then go
on to destroy (aka explode) the battery from over-voltage.
-- 
Don Malpass   [malpass@LL-vlsi.arpa],  [malpass@spenser.ll.mit.edu] 
  My opinions are seldom shared by MIT Lincoln Lab, my actual
    employer RCA (known recently as GE), or my wife.