[nJm]

My iBook G4's battery is on the way out, I'm sure I'll get around to buying a new one at some stage but for now I'd love the battery life monitor in OS X to be slightly accurate. At the moment what happens is I unplug the power cable and OS X warns me I'm running on limited power, and the battery life metre is red and shows "Calculating... remaining" as the time remaining. However I can then use my iBook with wireless and full screen brightness for about 40 minutes before it actually goes to sleep.

Is there some way to reset the battery metre so it is at least accurate for my old battery?

[pat++]

Yes. You need to recalibrate the battery:
http://docs.info.apple.com/article.html?artnum=86284

You might want to reset the Power Management Unit as well:
http://docs.info.apple.com/article.html?artnum=14449

[erniesthings]

I hope these steps work for you. The didn't help my battery. I didn't realize that you should let the battery drain and the recharge occasionally. After about 2 years it went into the crapper and would give me about 30 min max.

I just replace the battery about 3 weeks ago. I definatly won't let it happen again.

Good luck.