Mac OS X 10.3.6 Special Report: Battery indicator still shows remaining time but PowerBook/iBook sleeps

There is a highly varied issue where PowerBooks and iBooks will spontaneously fall asleep, without any sort of low-battery warning and with OS X reporting various levels of charge remaining on their batteries. Some users are only beginning to experience this problem after updating to Mac OS X 10.3.6 -- though we cannot state with certainty that there is a causal link.

MacFixIt reader Bobby Jones writes: "Since installing the latest upgrade, I've been having problems with the battery life on my 12" G4 Powerbook. When the battery indicator says I have 60 minutes of life left, my laptop goes into sleep mode and will only become active after I've plugged the adapted in to charge."

The most successful workaround we've been able to determine for this issue -- though clumsy -- is not allowing the battery to fully charge. For some users, when the battery is allowed to reach a a 100% full charge, the PowerBook falls asleep while still indicating a remaining charge. If the affected PowerBook is unplugged when it registers 98% or less, it will sometimes run properly through the full charge.

Other workarounds that have worked for some readers include:

• Calibrating the battery Knowledge Base article #86284 explains the PowerBook/iBook re-calibration process, which may work to correct this problem in some instances: "The Lithium Ion battery of an iBook or PowerBook computer has an internal microprocessor that provides an estimate of the amount of energy in the battery during charging and discharging. The battery needs to be re-calibrated from time to time to keep the on screen battery time and percent display accurate. You should perform this procedure when you first use your computer and then every few months thereafter." Damien Andrews confirms this workaround: "I too have experienced this problem. I was on a camping trip with limited access to mains power and needed to use my computer for business related work. I was conserving battery power by turning off the screen and using the computer in direct sunlight. Though the battery level was at 33 % the computer suddenly went to sleep. This was very frustrating as I had to return to civilization to be able to use it again. Once back in town I reset the PMU and then returned to my camp site but I experienced the problem again. On my next visit to town I re-calibrated the battery and that seemed to do the trick."
• Resetting the PMU Some users have reported that resetting their portables' PMU solved this issue. Apple provides details for performing the reset procedure for a number of portable models in Knowledge Base article #14449.
• Using "SlimBatteryMonitor" One solution that has proved successful for some readers is the usage of a third-party battery monitoring utility, such as SlimBatteryMonitor.
• Using a power adapter In-house, the method we most often use for solving this problem is the simple connection of a power adapter. Doing so usually allows the PowerBook to wake up properly (restoring interrupted open projects) and usually allows several more minutes of charge time even if temporarily connected to the external power source.

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