Hi Peter, Do you know what kind of batteries are in these Ryobi packs? I have old ones that are Nicad, and newer ones that are Lithium. It makes a big difference in how to approach rejuvenating them!
Nicad: If the pack is below a certain voltage, the charger won't even try to charge it. Try to charge it with a bench supply as Cor suggested. If the voltage comes up enough to make the Ryobi charger happy, great! Nicads aren't usually hurt by sitting around until a cell is dead. If that doesn't work, my nicad packs had screws, so I could open them up and look for bad cells. Nicads have a tendency to fail shorted if the voltage across them is reversed. In a series string, the "good" cells can force current through the "dead" cells and damage them. This happens if you keep using the drill etc. even after one or more cells is dead (i.e. when the tool slows down noticeably. Sometimes you can temporarily "fix" a shorted cell by applying a *momentary* pulse of high current (an amp or so). If the pulse causes the voltage across that cell to rise, then you can continue recharging it normally (at a current of 1/10th of its amphour capacity for 8-10 hours). If the dead cell's voltage does *not* come up after a few such pulses, the cell is shorted and must be replaced. Even if such a cell does recover, it often has reduced capacity and an excessively high self-discharge rate; so it's usually best to replace it anyway for best reliability. Lithium: If a lithium pack has too low a voltage to charge, try Cor's technique with a bench supply. My Ryobi lithium packs are sealed, so I haven't been able to get inside (without ruining them) to see what kind of cells are inside, or whether they can be repaired or replaced. Be very careful when experimenting with lithium cells! They can start fires which are very hard to put out! Lee -- Excellence does not require perfection. -- Henry James -- Lee A. Hart https://www.sunrise-ev.com -----Original Message----- From: Electric Vehicle Discussion List <ev@lists.evdl.org> Sent: Dec 10, 2023 6:05 PM To: Electric Vehicle Discussion List <ev@lists.evdl.org> Cc: Peter Eckhoff <evd...@gmail.com> Subject: [EVDL] Battery Testers I have a few Ryobi power packs that won't charge. This got me to thinking I would like to get into trouble shooting and battery testing. I've found a few sites on Youtube that discuss trouble shooting and battery testing. A number of sites use a Atorch DL24 [P] such as this channel: https://www.youtube.com/watch?v=YQQJHwC4hOY&t=20s Are there any battery testers that you have used and could recommend? _______________________________________________ Address messages to ev@lists.evdl.org No other addresses in TO and CC fields HELP: http://www.evdl.org/help/ _______________________________________________ Address messages to ev@lists.evdl.org No other addresses in TO and CC fields HELP: http://www.evdl.org/help/
