About the Low Battery Indicator
The onscreen low battery indicator appears if your MacBook Pro or MacBook Air has insufficient battery power to start up or wake from sleep. The flashing red battery icon indicates that your notebook needs to be charged.
The following two conditions will cause the low battery indicator to appear on your notebook's display for 8 seconds:
- The remaining charge capacity for the battery has become low (typically at 1%) and a power adaptor is not connected.
- The computer has a lower-powered MagSafe adaptor connected to it and the battery has reached 1% of the charge capacity.
Note: The battery image will flash once per second for up to 8 seconds when this occurs. It will alternate between the red and black battery images. If you don't connect the computer to a power sou rce before the battery image stops flashing, it will automatically sleep—this is an attempt to preserve the contents of the current session.
The low battery indicator will not be displayed onscreen, or will be dismissed, if either of the following occur:
- The Mac's battery is at 0% charge capacity and has already entered automatic system sleep.
- The battery was nearing the end of it's charge capacity and the low battery indicator flashes, but a power adaptor is immediately connected. In this case either:
- The computer suddenly has enough power to start up (or wake) before the 8 second pattern has concluded.
- The low battery indicator then appears solid (not flashing) for 8 seconds and the Mac enters automatic sleep.
- See this article if the low battery indicator appears but your Mac won't start.
- If the battery doesn't appear to be charging after a reasonable period of time, see this article on resetting the SMC.
- Mac Notebooks with the onscreen low battery indicator no longer have a battery charge indicator on the side of the computer.