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Late-2008 MacBooks: Battery issues

Users have noticed that the new MacBooks have some issues with the batteries. While they appear to run perfectly fine in most situations, when the computer is put to sleep the power seems to drain much faster than expected

CNET staff
3 min read

Users have noticed that the new MacBooks have some issues with the batteries. While they appear to run perfectly fine in most situations, when the computer is put to sleep the power seems to drain much faster than expected.

Apple Discussions poster madroberts writes:

"I have the 2.53Ghz, 4MB RAM, 320-7200RPM HD. The other night I unplugged it from the AC adapter and left it closed and supposedly in sleep mode for almost 24 hours. When I came back to use it the next night, the battery had drained all the way down and I couldn't restart it. This just doesn't seem normal." http://discussions.apple.com/message.jspa?messageID=8312009

In past MacBook models users were able to keep the computers in sleep mode for days and lose charge at only a few percentage points per day. The new models drain power at the rate of a few percentage points per hour. This problem seems to be an issue that affects many users, and seems to be coupled with the computer going into hibernation much sooner than expected when in sleep mode.

Additionally, users have noticed problems when trying to calibrate the MacBook's battery. In order to calibrate the battery, users need to charge it up fully and then let it run down to the point where the computer goes to sleep. This allows the computer to measure the full capacity of the battery and better determine the actual charge left in the battery during usage. When users drain the battery, the computer does not go into sleep mode, and instead seems to either go into "deep sleep/hibernate" mode or completely shut down. This could be the normal calibration behavior of the new MacBooks, but it differs from previous models and as such is probably not supposed to happen.

This problem could be due to poorly written drivers for the new MacBook hardware, or could require a firmware update. The chipset is completely different than previous MacBooks, and the systems include many other new hardware features such as DDR3 as the system RAM, and dual GPUs. It is clear the drivers for the system have been crudely thrown together for now, exemplified by the need for users to log out upon enabling or disabling the dedicated video processor in the MacBook Pros. This feature should be dynamically changeable, but currently this is not coded into the drivers.

For now, Apple's drivers will have to play catch-up with the new technology, and hopefully in the next OS update the power draining issues will be resolved. However, for now users might benefit from trying the following.

Potential Fixes

Reset PRAM and SMC Users can try resetting the computer's PRAM and system management controller to see if that helps the situation, since these hold some hardware parameters used for power management. To reset the PRAM, reboot the system and hold the options-command-P-R keys all at once until the system makes the boot chimes, and then resets and makes the boot chimes again. Hold the keys until this cycle happens 2-3 times, and then allow the computer to boot normally. To reset the system management controller on the new MacBooks, turn off the computer, unplug it, and then open the hatch and remove the battery. When this is done press and hold the power button for 5-10 seconds, and then plug everything back in and start it up again.

Try alternate settings In addition to hardware resets, users might try setting their computers to more power-conservative settings such as turning off the dedicated GPU for MacBook pros, and spinning down the hard drives, etc. Many of these options are in the Energy Saver system preferences pane.

Resources

  • madroberts
  • More from Late-Breakers