When I remove the battery from my MacBook the computer immediately shuts down, I notice the battery says its fully charged by the 4 lights on the back of the battery but the icon on the battery in the menu bar has an x in it.
I tried swapping my battery with my wife's (same model MacBook) but it doesnt fix the problem.
Any suggestions welcomed.
Apple does have a battery recall/fixing procedure on certain macbooks and macbook pros.
The battery of a MacBook or MacBook Pro computer may:
Appear to have no charge (zero percent)
Be
unable to power the computer by itself; the computer might work only
when it is connected to the MagSafe power adaptor, which only shows a
green LED
Appear with a black "X" icon on the menu bar
Shut down, then remove and reinstall the battery. Test for the issue(s) again.
Connect the MagSafe power adaptor (if you haven't already) and see if the behavior continues.
If the issue(s) persist, download and install the Mac OS X 10.4.9 Update.
If the issue(s) persist, Download and install Battery Update 1.2.
If,
after installing the Mac OS X 10.4.9 Update and Battery Update 1.2, a
black "X" still appears in the menu bar, contact apple by calling 1-800-MY-APPLE (1-800-692-7753)