Most of the newer Macs come with efficient hardware and software which help you preserve energy, but the biggest drain on your precious Mac’s battery will largely be the programs you use. For instance, if you decide to encode a lengthy high-quality file which you’re planning to upload on Youtube (which I’m doing right now), your Mac’s processor’s cores will be utilised to their maximum, and even a full charge will be left with a short amount of battery life available.
To help users preserve battery life, Apple has implemented features like App Nap to pause unused programs in OS X Mavericks. Another feature that was introduced with the new OS was CPU timer coalescing to allow processors to maintain a lower average energy usage. In addition to these automatic features, you can use common power-saving methods such as dimming your Mac’s screen to a minimum, disabling unused Bluetooth and Wi-Fi controllers etc. However, most people know that the benefit of these steps will be completely nullified if you have a program that is computationally demanding.
To look this up in prior version of OS X, users would mainly use Activity Monitor’s %CPU usage calculation. However, if you didn’t carefully observe and made a mistake, you could have comprehended a brief burst of activity from one program as being something more extensive causing the battery drain.
In the new OS X Mavericks, Apple has offered ways to help users better assess poor battery life. If you open the Energy section of Activity Monitor, you will see a default column labeled “Energy Impact” that is a relative measure of the power used by that program’s demand on the system hardware. Sort the process list by this column, and you will be able to see persistently high numbers that might be worth closing down to maintain battery life.
Note: By default, the Energy section of Activity Monitor only shows user applications run in the past 8 hours. This will overlook background processes that could be also contributing to lower battery life. Therefore, go to the View menu and choose “All Processes” to get a better view of what is running.
In addition to the Energy Impact rating mentioned above, you can also sort the list by the column labeled “Requires High Perf GPU”. This will let you see which programs are making the system use the powerful and more demanding graphics card on systems that ship with two. If on your Mac, the Graphics Card status in the Energy View says “High Perf”, you can locate and quit any programs that say “Yes” in the “Requires High Perf GPU” column.
In addition to the Energy Impact rating, you can sort the list by the column labeled “Requires High Perf GPU” to see which programs are keeping the system using the more powerful (and more demanding) graphics card on systems that ship with two. If the Graphics Card status in the Energy view shows “High Perf.” then you can try locating and quitting any programs that say “Yes” in the “Requires High Perf GPU” column.
Lastly, while there’s no doubt that Activity Monitor is a great tool for assessing process load, you can also take a look at the applications that have a significant energy impact by opening the Battery menu extra (which can be enabled by checking “Show battery status in menu bar” in the Energy Saver system preferences). You may have to wait a few moments, but then you will see a listing of apps that are using significant energy. Selecting one of the listed applications will open up Activity Monitor with the program selected, so you can see other statistics about it.