WARNING: Please do not attempt any of the procedures described here unless you know EXACTLY what you are doing. An iBook is an expensive item to replace and if you get this wrong you will risk damaging your computer. If you have any doubts, DO NOT do any work on your battery pack. If your iBook or battery pack is still under warranty then contact Apple and get them to fix it. We can not be held responsible for any unintentional damage you may do to your computer!
We have owned a dual USB G3 iBook for about two years now. It's a very nice piece of hardware running an extremely good operating system, and it's the tool of choice for on-the-move computing. We've had to replace a power adaptor and a reed switch in the display but otherwise it has been quite reliable.
A few weeks ago the battery stopped working. It didn't lose charge as you'd expect, it just suddenly went from being able to run the computer for 2 hours to being unrecognised by MacOS with a little "x" where the battery icon should be. Pressing the button on the bottom of the battery resulted in no LEDs being lit. Since a new iBook battery pack costs £100 here in the UK, we decided to see if we could fix it rather than buy a new one. We searched the web and followed all the advice we found, all to no avail. Reading up on the subject of Li-Ion battery packs it became obvious that this is an unusual failure mode, except among Apple owners for whom it is apparently very common. Reading further we encountered the suggestion that it could be due to the onboard battery monitor crashing.
A modern Li-Ion battery pack is not simply a plastic box filled with cells. It will normally contain a battery monitor circuit board whose function is to monitor the cells and protect them from excessive charge and discharge current, and excessive temperature. In the case of the Apple packs this circuit is a small embedded microcomputer that talks to the iBook to inform it of the battery status, if this computer crashes then MacOS is unable to "see" the battery. Thus a battery pack with perfectly good cells can "die" without warning, and since there is no reset button on the battery pack it can not easily be brought back from the dead without opening the pack up and physically disconnecting the microcontroller.
To find out whether or not the cells in our pack had died I tried connecting a 12v car indicator bulb to it. Using a voltmeter I found that the outer contacts on the battery connector carried the full battery voltage, connecting the bulb to these contacts resulted in it being lit brightly for nearly 2 hours. This led me to believe that there was not much wrong with the cells themselves and as suspected the battery monitor had crashed. Interestingly the cells were recharged when plugged back into the iBook, despite the charge indicator light not changing from green to orange.
The decision was made to open the pack up and try disconnecting the battery monitor to reset it. We were fortunate enough to be given someone else's knackered old iBook battery pack that has only about half an hour's capacity (for which we are TRULY thankful!) so at least we had a pack we could use to run the laptop if I couldn't bring our original pack back to life.
The iBook battery pack is the most simple pack I have ever seen to dismantle. For this I congratulate Apple. Simply undo two tri-wing screws and gently lever the cover off to expose the cells. I did not have a tri-wing driver small enough, but I found a miniature flat-blade could be made to fit with care.
Inside the pack I found six 18650 Li-Ion cells wired in series as 3 packs, each of 2 cells in parallel. The battery monitor lives on two circuit boards tucked in behind the battery connector. Because the monitor needs to keep an eye on all the cells at once, it has 4 wires from the stack of batteries, one on the -ve terminal of the stack, and 3 from the positive terminals. To disconnect the monitor I simply unsoldered the 3 positive wires, starting with the highest voltage one and moving down the stack of cells. Connecting it again was simply a case of resoldering the 3 wires I'd just disconnected, in reverse order. I knew at once that the battery was working again because the battery condition LEDs came on. Success!
If you attempt this process, please note that this involves soldering on a "live" circuit board with potentially static sensitive components and a set of cells that when shorted out can quite happily dump enough current to start a fire. Because of this it is a job best attempted with extreme care by someone who is confident in their soldering skills and is equipped with a temperature controlled iron and a solder sucker to remover surplus solder. As I said at the top of the page, get this wrong and your iBook could be toast! If in doubt, don't!
Here is a picture of our iBook battery pack with its lid removed showing the wires and the order of their desoldering. First-Black wire. Second-Yellow wire. Third-Orange wire. Your battery may be different from this one, this is the only iBook battery I have ever opened so make sure that you check very carefully that the wires you intend to desolder are the three battery positive terminals.
When I had reattached the wires I carefully replaced any pieces of insulating tape placed there by Apple and reassembled the pack by slotting the lid back in place and doing up the screws. You may prefer to use a small amount of glue by the connector, if you do make sure that it is a glue that can be parted should you ever need to open the pack again.
Putting the reassembled pack in the iBook resulted in the orange charge light and MacOS recognising the battery immediately. It will run the laptop for over two and a half hours so as far as we are concerned it is back to new again.
In conclusion, this is a fix for one failure mode of Apple iBook battery packs, though it is not one for the faint hearted. I think Apple have not served their user base well by creating a battery that can be rendered inoperable by a software crash alone, and then not admitting that they have a problem. Not every iBook owner is lucky enough to be an electronic engineer so for most owners this is just another "Apple tax" of £100. Shame on you, Apple! Even a reset button on the battery would be acceptable.
© copyright John W. List 1998 - 2007