Many people don't realize that notebook battery life ratings are generally estimated as the "maximum" battery life on the lowest power settings. This means:
- Lowest brightness setting.
- Lowest processor settings (most CPUs will throttle up or down depending on the burden placed on the CPU).
- No use of optical drives.
- No use of any internal communications cards. This includes Wi-Fi, Bluetooth, and internal WWAN cards.
- No use of USB ports or any other power-consuming ports.
If you want to improve battery life, make sure you're doing what you can to reduce power consumptions in the areas described above. The easiest way to improve battery life is to decrease brightness and reduce your CPU settings. Turn off your wireless cards if you're not using them.