PowerBook and iBook computers running a version of Mac OS X 10.2 may not display an alert message that the battery is low before going to sleep.
This will only occur in Mac OS X 10.2 through 10.2.8. If you are running a version of Mac OS X 10.2 on a PowerBook or iBook, be sure you connect the computer to its power adapter once it goes to sleep.
Important: Sleep, or low-power mode, preserves the state of the computer for a period of time, but if AC power is not connected and the battery is completely emptied, unsaved documents and data that is in memory will be lost.