Apple MacBook Pro (17-inch) - Manual (Page 75)

Chapter 3 Using Your MacBook Pro 75
If your 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
connected to a power adapter, it’s best to shut down your computer. If you put your
MacBook Pro to sleep to replace the battery, wait until the sleep indicator light is
pulsing before removing the battery. Although your computer will shut down when
you remove the battery, you won’t lose any data, and your computer will return to the
state it was in before the battery change.
Important: If only one indicator light is on, very little charge is left. If no lights are
visible, the battery is completely drained and the computer will not 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 “Removing the Battery” on
page 82 and “Replacing the Battery” on page 89).