My 2007-era black MacBook uses a battery that needs to be regularly calibrated; that is, once a month, it needs to run down to zero and then charged back up. One of the Genius Bar guys told me that the worst thing to do to a battery is to leave it plugged in all of the time. The battery needs to run for some periods of time on its own; if the laptop is plugged in all of the time, the battery's life and functionality can be impaired.
Or something like that. Many people in my orbit think of me as a tech whiz, but I'm really not. I just have time and spend it playing with stuff, reading the documentation, and learning as I go.
Anyway, my MacBook often stays on my desk and doesn't travel with me to work or school as often as it used to. So it's a good idea for me to cycle the battery by running it down to zero once a month and recharging it. Apple calls this process calibrating the battery, enabling the menubar readout to more accurately reflect the battery's charge state. You can read Apple's recommendations for battery calibration here.
To ensure I do this monthly, I've set up the following process:
- I have Memotome fire off an email to me on the third Saturday of each month. The notice contains Apple's instructions on calibrating the battery and a link to its web page.
- Before I go to bed that night, I unplug the MacBook. I turn up the screen brightness to maximum.
- I run an app called Caffeine (free at the App Store), which keeps the display from going to sleep. I set it to run for 5 hours, which is far longer than my fully charged battery will last. Caffeine is also useful if you're watching a video and don't want the screensaver to kick in.
- I start playing a ripped DVD movie or a long video podcast in iTunes (Kevin Pollak's Chat Show or MacBreak Weekly are usually good for at least 90 minutes). Playing a video requires more juice from the battery.
- I close the door to my office so the Mac can go to sleep in peace.
At some point during the playback, the Mac will start to complain that it's running low on power and it will eventually go to sleep. If I'm around, I can shut down the Mac or force it to keep playing the video till it collapses; usually, I let it go to sleep on its own. Apple recommends that the MacBook sleep in that state for at least 5 hours. When I go into the office the next morning, I plug the power cord back in and wake up the computer.
This is a pretty simple reminder process that I've used for years. If only reminding myself to cut the grass were so simple.