Maximize battery cycle time and extend Macbook battery life

June 28th, 2009 by Mark Nanut Leave a reply »

batteryWant to extend a working session on a Macbook Pro battery from, say, 2 hours to 3.5 hours? Then read this post. If you are looking merely how to extend your Macbook battery life to make it last longer in terms of months or years, there are loads of other resources on the web. Still, applying the methods explained in this post will result in less battery drain, which in turn will also extend overall battery life of your Macbook Pro. In this post I’m explaining primarily methods to squeeze most juice out of your Macbook battery in a working session, and only indirectly – how to extend Macbook battery life.

I searched for a bit more advanced and less known methods to optimize Macbook (Pro) battery session beyond the usual ones (turn down screen brightness, turn off Airport and Bluetooth etc.) . I found a couple of promising ones, implemented them and I am happy with the results, to the extent that I may not need to buy a new Macbook Pro battery just yet. It’s now 39 months old with 506 loadcycles, and still has 75% capacity, which is almost spectacular for its age. Fully charged and optimized it now blasts out a bit more than 2.5 hours of working time – before the optimization I could hope for max 1.5 hours of fun. 66% percent increase in battery session time is certainly worth a look at, regardless of what condition your battery is in. So here is how to max out your Macbook battery.

1. Use Coolbook

Downclock and lower the voltage for different predefined processor speeds with the help of Coolbook. This method is by far the most effective if you want to prolong battery session, still it may be a bit tricky to set up for an average user. I’m not going to explain this method in detail because it is well documented here and in the Coolbook manual. But briefly, what worked in my case, was to find a processor speed/voltage pair that works reliably on my Macbook, that is the highest stable clock frequency at the lowest possible voltage (in order to minimize battery drain), which is 0.9500V.

In my case, this highest stable frequency is 1,67 GHz and with the help of Coolbook driver my Mac is now preset to run with 1670 MHz on 0.95V when it’s using battery power. By default that would be 1670 MHz at 1.14V, so energy savings are obvious, not to mention that MBP runs cooler, which also keeps fan RPMs at bay.

The result is that battery now drains slower than before. Still you will have to experiment to find appropriate freq/voltage pairs for your respective machine. Expect some kernel panicking before you set things right. Backup beforehand.

Offtopic: when running on AC power, my setting is max speed (2004 MHz) at the lowest stable voltage, that is 1.05V (instead of 1.22V). This helps keep my MBP cooler, and pushing the CPU load to the limit now reaches temperatures of max. 80 degrees Celsius (could reach temps above 90 C before that).

Download Coolbook:

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Most Commented Posts

  • danpalmer

    In response to the defragmenting, Mac OS does not set files fragment so this is a pointless waste of time unless you have less han 5% disk space left, at which point there is not enough room for the automatic defragmenting to work. However at this point you will get more performance increases from cleaning up the disk than from defragmenting.

  • nemesit

    just look at an osx hdd its fragmented like hell it's just not as bad as with other systems but it is a pain if you ever want to repartition your drive

  • Lucas

    Hello. What defragmenting software do you suggest to use, preferably free? I was looking around for a while (been some time ago though) and didn`t find just what I was looking for. Thanks

  • Mark Nanut

    iDefrag from Coriolis, not free unfortunately:

    Haven't used it in a while, especially since I got an SSD drive.

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