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Friday, March 6 2009 @ 3:55 PM PST

Description: Apple laptops ship with well-engineered battery systems that are advertised as providing some of the longest runtimes when compared with portable computers with similar specifications. Despite this, while some people are able to get times similar to those advertised by Apple, others are frustrated with their experiences of these runtimes being truncated by at least an hour from the advertised times, even on brand-new machines. This is mainly due to a difference in Apple’s testing conditions versus the way an average user will run the laptop. It’s best to consider the advertised battery times as being at the very high end of what’s achievable, since in Apple’s tests the environmental and computing conditions are optimal, and the batteries are fresh.

There are many factors that can contribute to battery performance, including age, usage, calibration, environmental factors, and overall load. When someone goes to a cafe or library and browses the Internet while listening to music, even with seemingly minimal load on the computer, many tasks are performed that can quickly drain the battery. Bright screens and running multiple applications are just a few tasks that can affect battery life.

Tips for basic computer usage

For basic computer usage, here are some tips for how to run the computer to lengthen the battery life. This involves minimizing the computing experience, but if done correctly, you can increase the battery runtime, and sometimes well above the advertised times.

1. Turn off Bluetooth and Wi-Fi. If they’re not needed, turn off wireless technologies, since these will consume battery power to both broadcast and receive wireless signals. This will not only disable the hardware (or at least put it in a low-power mode), it will also prevent the system from running driver tasks to control these devices. If networking is required, you should use an Ethernet connection, if available.

2. Dim the screen. The screen is one of the largest battery drainers in the system, and we recommend that you dim the screen as much as possible. Ideally, you should run the screen on the first brightness setting for the best battery life. This can take some getting used to, but the difference in the time yield between minimal brightness and full brightness can be hours.

3. Turn off the screen when pausing work. Depending on what’s being done on the computer, there may be times where you are thinking about your work, or not actively looking at the screen and interacting with the computer. This can be for a few seconds or minutes, but one habit that will increase the battery life is to fully dim the display when not in use. For instance, before taking a break to stretch or chat with people, hit the dim key until the screen turns off completely. Then only brighten the screen enough to do the next few tasks and dim it again when done with those tasks. This habit can greatly increase the battery runtime.

4. Turn off keyboard backlighting. As with the display, the backlight on the keyboard should be turned off unless you absolutely need it, and then only turn it on minimally.

5. Put computer in sleep mode when taking long breaks. Avoid turning off the computer, since booting it up will drain the battery. Instead, if you are taking a break from you work for 5 to 10 minutes, put the computer in sleep mode. This can be done via the “Apple” menu, or can also be done by pressing the power button followed by the “s” key when the shutdown options appear. This may be a slightly faster way of performing this task than using the menus.

6. Optimize System Preferences settings. In the “Energy Saver” System Preferences, you should switch over to “Better Battery Life” graphics when running on the battery (for newer MacBook Pros), and also check the option to put the hard disks to sleep whenever possible. There are several additional system settings that can increase battery life:

Turn off Spotlight by deselecting all items in the “Search Results” list of the Spotlight System Preferences.

Turn off “Automatically adjust brightness…” in the “Displays” System Preferences.
Disable screen hot corners (accessible in the “Screen Saver” or “Expose” System Preferences) to prevent accidental activation.

Avoid using Spaces, Expose, or Dashboard. If you have already activated Dashboard, you can quit by restarting the Dock. To do this, enter the following command in the Terminal:

killall Dock

Disable the infrared remote control receiver in the “Security” System Preferences.

Turn off unnecessary sharing services.

7. Disconnect peripheral devices. Any peripheral device will take some power to run, and we recommend you minimize the use of these devices. USB mice, hard drives, and even thumbdrives all will take some energy to run, and as such, will lower the runtime of the computer. In addition, avoid using the CD/DVD drive.

8. Turn off unnecessary applications. Any open application will take up additional CPU cycles. Any antivirus programs, media players, menu widgets, and utilities that you have installed will use CPU cycles, and we recommend you quit these applications while on the battery. Minimize Web browsing, and when you’re done viewing a Web page, close the browser window.

Tips for battery maintenance

Beyond optimizing how you run the computer when on the battery, there are some ways you can help keep your batteries as healthy as possible. The following tips should ensure longevity of your batteries.

1. Regularly calibrate the battery. While batteries do lose their capacity with usage, they will also die over time without usage. This doesn’t mean you should use the battery all the time, but it is good to periodically run it down to ensure it’s being fully used on a regular basis. Regardless of use, we recommend you regularly calibrate the battery (once every 1 to 2 months), which will not only ensure the battery is being used, but will also set the computer to properly determine the remaining time left in the battery. To calibrate the battery, you will have to charge it up fully and then allow it to fully drain. More on calibration can be found in this Apple knowledgebase article:

2. Reset system management controller. The system management controller helps power management in the computer, and if there is corruption in the SMC’s settings, it can potentially drain the battery faster than normal. Reference this article for instructions on resetting the SMC for a particular MacBook model:

More information:

Apple has a few resources on its computer batteries, including some additional information and tips on batteries in portable devices.