MacBook battery life FAQ: Can you offer some tips on how to extend MacBook battery life?
I noticed on a few recent trips to Panera Bread, Starbucks, and Barnes & Noble that my MacBook battery life was not what I expected. In fact, it was downright short. I was getting less than an hour out of a single, complete MacBook battery charge, and even though my MacBook Pro is pretty old by now, that is unacceptable.
How I extend my MacBook battery life
I decided to investigate my battery life problem, and in the end, I've been able to at least double my MacBook battery life by following these steps:
- Turn the MacBook monitor brightness down to just what I need.
- Fire up the disks less often. (Don't press Save all the time when editing documents.)
- Turn off Firefox (Firefox often seems to eat the CPU and RAM).
- Turn off Time Machine.
- Turn off the MacBook wifi networking (AirPort).
- Run the "top" command or the Activity Monitor and see if a process has gone crazy.
I turn off the MacBook Wi-Fi networking as a last resort, but really, this isn't a big deal for me, because I usually go to these places to write articles or software code, and not having the distraction of the internet is a nice thing then.
Improving MacBook battery life - discussion
The Mac Activity Monitor application has been a great tool to help improve my MacBook battery life. Using it, I've seen that Firefox goes nuts every once in a while. When I have wall power, restarting it isn't a big deal, but when I'm running on the battery, and Firefox is in some tight loop eating my CPU, it also eats my MacBook battery life. So my first recommendation is to shut down Firefox if battery life is important to you.
Once I had Firefox turned off I realized I didn't need the wireless card running, so I turned it off from the main menubar. While I was up there at the menubar I also turned off the Time Machine. I'm not sure if this is completely necessary -- you'd think it would be smart enough to know when the network is on or off -- but I've seen rogue commands running in the Activity Monitor that seem related to Time Machine, so now I just automatically turn it off.
(As a nice side effect of turning off my networking capability, I find that I fool around a lot less and get right to work. I thought I was focused in my previous life as a consultant, but now that I spend most of my time writing, I'm a really big fan of this productivity gain. It's funny, all those email messages really can wait.)
Analyzing MacBook battery life with the "top" command or Activity Monitor
As the applications you use are likely to be different than the applications I use, the Unix "top" command or the Mac Activity Monitor application are likely going to be your best friends in solving your MacBook battery life problems.
I'll cover the Activity Monitor more in a future post (see this Mac Activity Monitor tutorial), as it's a great tool for troubleshooting battery life problems, and other problems. But for now, you want to start the Activity Monitor, and then sort the its main table by the "CPU" column. If something is running and using more than just a few percent of the CPU, you may have a problem. For instance, I just looked at my results as I sit here this morning, with Firefox turned off, and as I watched it run for a few moments, the highest CPU use by a running process was 3.4%.
How to start the Mac OS X Activity Monitor
I look at processes so often right now I've made a shortcut to the Activity Monitor available on my Dock, but if you want to run it, here's where I found it:
- On the Dock, click Applications.
- Click Utilities.
- When the Finder window comes up, double-click the Activity Monitor icon.
- Click the CPU table header to sort the data by CPU usage.
(Note: On Mac 10.6 (Snow Leopard) you won't see the Mac Finder window in Step 3.)
Products discussed in this post
- I have one of the original Intel-based original MacBook Pro notebooks, with a 2GHz Intel Core Duo, and 2GB RAM.
- I'm running Mac OS X 10.5.6.
- My Firefox version is 3.0.10. (Wow, I just started Firefox to see what version I have, and for it to start up it just ate 6% of my CPU! I did have six browser tabs open from my previous session, but that seems like a heckuva lot of CPU.)
MacBook Pro battery life - follow-up
As I put the finishing touches on this MacBook battery life blog post, I'm now running on wall power. I just fired up the Activity Monitor, and sure enough, Firefox is using over 10% of the CPU, while I'm over here typing in my text editor. I don't know if the current version of Firefox has a problem, or one of the plugins I use has a problem, but my recommendation to turn it off to save your MacBook battery life stands. (As a second follow-up, this time on May 19, 2010, the Firefox memory and CPU problems continue. At this moment, Firefox is consuming over 600 MB RAM on my MacBook Pro, with only three tabs open.)
Finally, I also learned that you can improve your MacBook battery life by calibrating the battery.