Information Technology Reference
In-Depth Information
The MacBook Air lithium-polymer battery doesn't suffer from the memory effect. This means you can run
MacBook Air on battery power for as long as you want — 2 seconds, 2 minutes, 2 hours, or whatever you need
(within the confines of the battery's capacity, naturally). However, all lithium-based batteries slowly lose their
charging capacity over time. You might be able to run MacBook Air on batteries for 4 hours today. However,
later on you'll only be able to run the computer for 3 hours on a full charge.
You can't stop this process, but you can delay it significantly by periodically cycling the MacBook Air battery.
Cycling
— also called
reconditioning
or
recalibrating
— a battery means letting it completely discharge and
then fully recharging it again. To maintain optimal performance, you should cycle your Mac's battery once
every two months or so.
Paradoxically, the less you use MacBook Air, the more often you should cycle its battery. If you often go several days,
or even a week or two, without using MacBook Air, you should cycle its battery at least once a month.
Before getting to the steps, bear in mind that properly cycling the MacBook Air battery includes leaving the
computer off for several hours. Therefore, cycle the battery only at a time when leaving it turned off won't be a
problem.
Follow these steps to cycle the MacBook Air battery:
1. Make sure the MacBook Air battery is fully charged.
That is, either make sure that the battery status
icon shows 100 percent when you display the percentage, or check that the light on the AC power connector
is green. If the status is less than 100 percent or the light is orange, leave MacBook Air plugged in until the
battery is fully charged.
Sometimes the MacBook Air battery shows a battery status of 99 percent and never reaches 100 percent. If the AC
connector light shows green, go ahead and treat the battery as fully charged.
2. Leave MacBook Air in this fully charged state for at least 2 hours.
3. Disconnect the MacBook Air AC power connector.
MacBook Air is now running on battery power.
4. Operate MacBook Air normally by running applications, working with documents, and so on.
When the battery status reaches 5 percent, your Mac warns you that it's now running on reserve power, as
shown in Figure 9.6.
