In a message dated 2/27/02 5:16:21 PM, [EMAIL PROTECTED] writes: > >In a message dated 2/27/02 4:21:07 PM, [EMAIL PROTECTED] writes: > >>Thanks for the pointers. >> >>How would you suggest I go about using a power supply to zap the >>individual cells? I'll use my fog lamp connectors on my car as a last >>resort only, so I'm curious about trying the other methods first. >> >As mentioned, the least likely to be damaged item is a battery charger. >Don't forget that you want enough juice to "hit" the cell quickly. A >typical >charger is able to output around 10 amps instantanous current which should >do >the trick. Also, make sure you get the terminals right. The problem with >charging at a high amp rate is that you can literally melt the battery and >case! > >Good luck with it and be careful! >Andrew
I have found that using a big electrolytic capacitor (high capacitance value, at least 35-50VDC rating) works VERY WELL for this short burst of energy you need to "blast" a dead cell. You charge the capacitor with the DC supply, then touch the charged capacitor to the leads of the cell. This ensures the amount of energy available for this "zapping" is limited, and usually ensures there are no "big bang" explosions. You usually see quite a spark as you touch the leads of the capacitor to the battery (depends on how badly shorted the cell is), and sometimes you have to repeat the capacitor charge / cell blast cycle several times. This process works especially well, because the instantaneous current available from a charged capacitor is extremely high (di/dt starts at theoretical infinity when presented with a short circuit), but the high current is only available for a few milliseconds (depends on the capacity of the capacitor). And if you have the bench supply available that you talked about, you can charge the cap to 25-50 VDC, which usually gives a pretty good "blast" to the cell, and usually doesn't damage anything. Be careful out there! Joe ---------- Duo/2400 List, The friendliest place on the Net! A listserv for users and fans of Mac subportables. FAQ at <http://www.themacintoshguy.com/lists/DuoListFAQ.shtml> Be sure to visit Mac2400! <http://www.sineware.com/mac2400> To unsubscribe, E-mail to: <[EMAIL PROTECTED]> To switch to the DIGEST mode, E-mail to <[EMAIL PROTECTED]> Need help from a real person? Try. <[EMAIL PROTECTED]> ---------- Dr. Bott | 10/100 Ethernet for your 2400 is finally here! MPC-100 | <http://www.drbott.com/prod/mpc100.html> RoadTools $30 PodiumPad available at Apple retail stores, $20 Traveler CoolPad at Staples. Both in white for iBooks at <http://roadtools.com> Midwest Mac Parts ][ <http://www.midwestmac.com> After-market parts for Macs. ][ 888-356-1104 ][ MacResQ Specials: LaCie SCSI CDR From $99! PowerBook 3400/200 Only $879! Norton AntiVirus 6 Only $19! We Stock PARTS! <http://www.macresq.com>
