Casio HK1223 - Manual (Page 81)

Managing Power 3-9
Power-Saving Tips
In addition to your computer’s automatic power management, you can do
your part to maximize the battery’s operating time by following these
suggestions.
Do not disable Power Management.
Decrease the LCD brightness to the lowest comfortable level.
Disable the serial port if no device is connected to this port. (See
“Advanced Menu” in Chapter 5.)
If you work with an application that uses the serial port or features
wireless connectivity (LAN/WLAN/modem/GPS/Bluetooth), exit
the application when you finish using it.
Turn off the computer when you are not using it.