Symptom
When two batteries are installed in a PowerBook G3 Series (Bronze keyboard) computer with Mac OS 9.0, the Battery Monitor portion of the Control Strip only shows the time remaining for a single battery.
Solution
Install Mac OS 9 Update (9.0.4) from the Software Update control panel, or download it from
http://www.apple.com/swupdates/ .
If you do not install the Mac OS 9 Update, you can double the time remaining to get an approximate estimate of the available battery life. Although the time remaining indicated is incorrect, the PowerBook still uses and benefits from the second battery.