Possible Duplicate:
Is it better to use a laptop on battery or on AC power?
Is this true (For Dell laptops) ?
Possible Duplicate:
Is it better to use a laptop on battery or on AC power?
Is this true (For Dell laptops) ?
For what I know the answer is yes, it's always good to unplug battery when your laptop has power cable attached on it
Two separate issues:
You can remove the battery when the laptop is plugged into AC, so that the battery does not charge, but this is generally not recommended. Some systems won't operate at full speed when there is no battery. Some might not work at all. And imagine if the power goes out; you should have a built-in backup battery, but instead the computer dies.
If you almost always have AC, you should still occasionally unplug on occasion, even when it is on. The idea that you must "move electrons through" the battery to exercise it. If it is constantly topped off, the battery will lose its ability to hold a charge.