Your choice of how long by turning off the Wifi and dimming the screen a little. Get a lot my by opting for the next size up battery.
Bob
I am planning to buy a Dell Inspiron 600m next month, but before I buy it, I want to know how long battery life is. If somebody who owns this device with a good battery, I want to know how long it runs on battery and how long it runs on BATTERY Playing DVD.

Chowhound
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GameFAQs
GameSpot
Giant Bomb
TechRepublic