Ask Different is a question and answer site for power users of Apple hardware and software. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

So I got my first Apple laptop, a Retina MacBook Pro. Since macbook pro retina's battery are no longer easily switchable I'm concerned about it's life and would like to maximize it. I have few questions below.

How long it should be kept in A/C power? Is it okay to keep the laptop connected to A/C power more than 24 hours? Will it not be good for the battery if I keep it in A/C power more than 24 hours?

Is it okay to charge the laptop when the battery reach 75% or should I wait till it goes to 50% or 10%? What's is optimal %?

What's the best charging practices should I follow?

share|improve this question
Most of your question is answered here.… – bmike Dec 2 '12 at 16:49
up vote 4 down vote accepted

The batteries on all 2012 models self regulate, self calibrate and don't care when you charge them.

You might reduce their total lifespan if you never ever ever take it off charge. Ideally drain it past 20% remaining (better to run it all the way down) once every few months.

These days, portable batteries are like sealed car batteries. Maybe go in to the shop once a year to have it checked, but otherwise you can forget "caring" for it other than avoiding excessive heat (90 degrees F and up).

Any time you want, Apple can run extensive diagnostics on your battery (for free at the Genius Bar and also complimentary if you pay for AppleCare.)

share|improve this answer

I dont think there is an "ideal" charging mechanism for your Macbook. If you use your Macbook and you are working with it close to a power socket you should absolutely have it plugged it. Why make the battery go through more charging cycles when it doesnt have to or work on reduced power. Apple recommends that every so often you should let the battery run down completely and then fully recharge it (perhaps every couple of months). Dont worry so much about your battery, the hardware and Mac OS software will take care of your battery by themselves. Enjoy using that Retina display :).

A very explanatory video about Monitoring your battery on your Macbook can be found:!

(I previously asked if calibrating the battery on a Macbook would preserve battery life and was given a very good answer by bmike found here Is it advisable to calibrate the battery on a MacBook?)

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.