I'll second the successful zapping technique as used on NiCds ... I just brought back to life 2 cells from a 3 cell stack in a cordless electric screwdriver by zapping *individually* the cells that would not take a charge - even an attepmt at a brief HEAVY charge (which I have had postitive results with at times). Tool of choice was a "Sprague Powerlytic" 76,000 uF cap rated at 40 V *but* only charged to 20 V for the purposes of this resurrection attempt. I also immediately apply nominal charging current right after the zap - usually by using a suitable current limiting resistor in series with the 20 V charging supply. This resistor also serves to limit the charging current of the cap when the 20 V supply is turned-up. Jim ----- Original Message ----- From: "Jinx" To: Sent: Saturday, June 01, 2002 6:30 AM Subject: Re: [EE]: Laptop battery fading > > There's got to be a better way -- is there some form of battery > > cycler that I can purchase or build that will work for these (IBM > > Thinkpad 600x) batteries? > > I don't know if this will work with Li batteries (I don't know the > failure mechanism of them), but I've just resurrected the NiCd > battery pack for my camcorder. It had suddenly plummeted > from a couple of hours to a few minutes usage time. The pack > had to be cut open and then individual cells are zapped with > a charged capacitor (10000uF @ 20V) to punch through the > dendrite barrier. Often it's just one cell going funny that stops a > pack charging. Works fine on cordless drill and Dustbuster > packs too, and worth a go considering the price of a new one. > There are commercial zappers around that use a neon/strobe > type arrangement, but that's simply a convenient means to > an end > > -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads