There are two factors to take into consideration when discussing the battery voltage levels and the accompanying on-screen warnings:
- the battery warning voltage parameters are contained in the system enabler file, so if a new enabler comes out (such as in a system update or new system software) these voltages may change.
- when a battery is removed and then its voltage is checked, the voltage reading will be slightly higher since the battery is not under a load as it would be inside the PowerBook.
The voltages and their accompanying warnings for the PowerBook 500 series are:
- Full Battery: 11.7 - 12.3 volts
- 1st warning: 11.35 volts
- 2nd warning: 11.15 volts
- 3rd warning: 11 volts