Apple MacBook Pro (15-inch and 17-inch, Inel Core 2 Duo) - Manual (Page 28)

28 Chapter 2 Life with Your MacBook Pro
Using the MacBook Pro Battery
When the MagSafe power adapter is not connected, your MacBook Pro draws power
from its battery. The length of time that you can run your MacBook Pro varies,
depending on the applications you use and the external devices connected to your
MacBook Pro. Turning off features such as AirPort Extreme or Bluetooth
® wireless
technology can help conserve the battery charge.
If the battery runs low while you are working, attach your power adapter and let the
battery recharge. To replace a low battery with a charged one when you are not using
a power adapter, it’s best to shut down your computer.
You can determine the charge left in the battery by looking at the battery level
indicator lights on the battery itself. Press the button next to the lights and the lights
glow briefly to show how much charge is left in the battery. You can check the charge
with the battery in or out of your MacBook Pro.
Important: If only one indicator light is on, very little charge is left. If no lights are on,
the battery is completely drained and the MacBook Pro won’t start up unless the
power adapter is connected. Plug in the power adapter to let the battery recharge, or
replace the drained battery with a fully charged battery (see “Replacing the Battery” on
page 42).