> > >Rechargeable batteries are consumables and they wear out. Software > >cannot change the chemical decomposition that occurs. > > But doesn't it control the charging process, or is this purely a hardware > issue? > The bottom of the Duo never got warm as does my 5300 when charging > - presumably you think the battery simply failed suddenly? > I think that I was not really addressing the original post when I commented about software not being able to change the decomposition of a worn out battery. In fact, software does have some control of the charging process but only in as much as it is able to monitor what the battery voltage is, what the battery temperature is, and and how much "usage" the battery has had since its last full charge. Therefore, if you remove the battery (with the computer running, and using the AC adapter) and then you put the battery back in, the software now does not know the state of affairs of that battery (they have serial numbers, so the computer does know one battery from another). In other words, the software will not assume that the battery is fully charged just because it was the last time it was installed. So, the software has no choice but to start charging the battery while monitoring its voltage and temperature, and then making the decision as to its state of affairs, and when it should quit charging. But, if the battery is not a good, normally functioning battery, the software cannot really make the correct decision about charging it. In fact, it is a moot point because there isn't a correct way to charge a bad battery. Only a good one can be charged "correctly". My experience with duos and a number of batteries (and also with PB 145s and 180s) is that the batteries can fail in a number of different ways. One or more cells in the battery can exhibit "high resistance" (not produce current fast enough) but yet still give a normal correct voltage reading if not loaded. Another way they can fail is for one or more cells to act as a short circuit. In this case the total voltage of the battery will be less than it should. Another type of failure can be caused if the battery has been exposed to excessive heat, such as from over charging. This can cause a condition called voltage depression (often mistakenly referred to as 'memory effect') in which some or all of the cells work fairly normally except they will not charge up to the full voltage they should. They may only charge up to and retain about 1.1 volts per cell instead of 1.2 volts. In this case, the computer may overcharge the battery every time it charges because it is never seeing the voltage it is looking for. This overcharging heats the battery causing its voltage depression condition to worsen if anything. After having said all the above, I must point out that I am by no means any kind of authority on batteries. All of my knowledge is from reading and observation and deduction, i.e. putting two and two together, not from any formal training or professional experience. Greg ---------- 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> NineWire | If they are cool enough to host this list... Digital Solutions | ...you should check them out! http://www.NineWire.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>
