About Apple Notebook batteries
Calibrating is done to keep your battery status reporting as accurate as possible, and should be done the first week you get your Mac or a new battery. If you run on battery frequently, calibrate every 60 days or so. If you run plugged in most of the time or if you infrequently use your notebook, calibrate every 30 days or so.
If you interrupt the calibration process or feel that you didn't do it properly, it's fine to start over and re-calibrate. You won't hurt anything.
Calibrating a portable computer battery
To check battery status, use
iStat Pro or
coconutBattery or
> About This Mac > More Info... > Hardware > Power > Charge Information:
Be aware that
battery readings are not 100% accurate, so if your brand new battery health is somewhat less than 100% or if it fluctuates up and down over time (100%, 96%, 99%, etc.), don't worry. This is completely normal. It's also normal for it to stop charging when you reach 97% or 98%, etc.
You don't have to worry about anything unless your battery health drops to under 80% with fewer than 300 cycles. In this case, assuming your battery is properly calibrated (so the readings are as accurate as possible), you may have a defective battery. If so, contact AppleCare to see if they will replace it.
Determining Battery Cycle Count
A charge cycle means using all of the battery’s power, but that doesn’t necessarily mean a single charge. For instance, you could use your notebook for an hour or more one day, using half its power, and then recharge it fully. If you did the same thing the next day, it would count as one charge cycle, not two, so you may take several days to complete a cycle.
Apple does not recommend leaving your portable plugged in all the time.
AppleCare support recommends that if you leave your Mac plugged in most of the time, unplug it every 2 or 3 days and run on battery down to somewhere around 50%, then plug it back in. That keeps the electrons moving.
Also, it is
not recommended to run your Mac on the A/C adaptor with the battery out.
As long as you're running it on battery at least every few days and calibrate every month or two, you'll be fine. Relax and just enjoy using your Mac!
