For laptops or any portable device, perhaps obviously one of the more important features is battery life, and how to get the most time out of the device without needing to plug it in.
Apple ships its laptops with an advertised 5 to 7 hours of battery life, but depending on how you use your system you may find the battery life to be well below that. For instance, my 2009 MacBook Pro gets about 5 to 6 hours of battery life instead of the advertised 7 to 8 hours. This is remarkable battery performance given the battery's age and heavy usage, but it is still below the initially advertised capacity.
Apple's batteries should last well into five years of service, but over time it is expected for a battery's capacity to diminish. Nevertheless, there are a few things you can do to help maximize both the battery's longevity in addition to the available time on a given charge.
Increasing battery longevity
While Apple's batteries are serviceable, in many systems the battery is built into the device and to replace it would take a little disassembly that at the very least may be a cumbersome procedure. To help prevent the need for this, you can do a few things to increase the overall lifespan of your battery.
- Use the battery
Some people may think if they do not use their battery then they will be essentially "putting it on a shelf" to use at a later date. Unfortunately this is not the case and batteries that are not used can develop dead spots that will no longer hold a charge properly.
- Avoid heat and cold
If you are in areas where the temperature is in the upper 90s or below 50 degrees F, avoid using the battery on your system. Unfortunately even with the device plugged in, the system will still use the battery to a small degree, which can damage it if the device is regularly used with the battery at temperatures beyond this range. If you plan on storing your laptop, ensure that it is fully shut down and then you can store it within the more extreme temperature range of -13 degrees F to 113 degrees F.
- Store the battery half-charged
If you plan on stowing your laptop for a while, charge the battery about halfway before doing so, but then be sure to remind yourself to check the battery every six to eight months to make sure that the charge is kept at around half of its maximum. This will ensure that the battery does not go in to a deep discharge state.
If you do not use your laptop's battery, then calibrating it regularly will help ensure a longer lifespan. In addition, even if you do use your battery, then calibrating it helps make sure that the system will properly report its charge state and minutes remaining when in use by adjusting the battery's working charge range. To calibrate the battery, it's best if you find a day in which you will not need to use your system. Turn on the system and start a few programs that will really work the system (i.e., play movies, music, and games simultaneously, with the display's backlight on full brightness). With doing this, the battery life should diminish much faster than if you just let the system sit.
When the low battery warnings display, allow the system to automatically go into sleep mode and then let it stay in this mode for a few hours. If you've started this procedure late in the evening then let the system sit overnight without being plugged in. This will ensure the last residual charge in the battery gets drained. When this is completed, plug in the system and allow the battery to fully charge again, which should take a couple of hours.
Increasing per-charge performance
Beyond battery longevity, you can increase the life of your battery by reducing the power draw of the computer, which can be done through observing a few options.
- Turn off Bluetooth and Wi-Fi services
Wi-Fi controllers can take a fair amount of power to operate, so turning them off when not in use can increase battery life. This is more prominent in cell phones and other mobile devices, but is also a factor in laptops. In OS X, you can enable the Wi-Fi and Bluetooth menu extras, through which you can enable or disable the respective services.
- Dim or turn off computer-generated light sources
One of the biggest power draws on a laptop is the screen, and any other system that generates light. Use the brightness controls to dim the screen as much as possible, and also turn off the keyboard backlight unless it is needed. Optionally if you have an external monitor handy then you can connect that to your laptop and completely dim the built-in display to save even more battery life.
Make ample use of sleep modes
If you have a mechanical hard drive (HDD) in your laptop, then set your system to sleep after a couple of minutes of not being used. With a mechanical hard drive you will need to weigh the benefits of putting the system to sleep with the drawbacks of requiring the drive to spin up every time you wake the system again. If you rapidly put the system in and out of sleep, the drive will continue to work and drain battery life. On the other hand, if you have a solid-state drive (SSD) in your system, then you can more extensively use sleep mode to help preserve battery life. SSD devices use far less power than a mechanical drive, and therefore can power up and down without draining the battery as much.
If you don't know whether you have an SSD or an HDD storage device in your laptop, simply restart your system and put your ear to the computer case. If you hear any chattering, clicking, and whirring noises that sound mechanical, then you have an HDD. However, if any sounds you hear are not mechanical then you likely have different problems to deal with.
- Avoid peripheral devices
USB and FireWire devices will use extra battery life, especially if they do not have their own power adapters. As a result, avoid using them if at all possible when your system is running on its battery. If you do need to use an external hard drive or another peripheral device, only keep it attached for the time it takes to complete your data transfer, and then disconnect it. Consider waiting until you have access to AC power.
Quit applications when not in use
Be aware of the active programs on your system and quit them when you are not using them, even if you have them minimized or hidden in the background. Do this especially if the programs you are using extensively interface with hardware or loop and stream, which include virtualization tools, media players, system monitors, games, and graphics manipulation tools. Even if programs seem like they do not use a lot of the CPU, developers might integrate interface elements that will keep the graphics processor active.
Also avoid using various window management tools like Spaces or Mission Control, which make use of the OpenGL graphics library and will keep the system's graphics processors active.
Use onboard GPUs
In some of Apple's laptop systems, there is both a dedicated graphics processor and one that is built into the system controllers (commonly referred to as an "onboard" or "integrated" graphics controller). Forcing the system to use the onboard graphics processor instead of the more powerful dedicated one is a quick way to give yourself another 30 to 60 minutes of battery life. On some systems you can do this in the Energy Saver system preferences by selecting the "Better Battery Life" option, but in newer systems with automatic GPU switching there is no option to force the system to only use the integrated graphics processor. As a result, you can use tools like gfxCardStatus on these systems to ensure the dedicated graphics processor is not used when on battery power.
Recently Apple released a new knowledgebase article that recommends against using third-party tools like gfxCardStatus, which force the system to use only one specified graphics processor, claiming these tools do not necessarily preserve battery life; however, this recommendation is a touch hypocritical. In Apple's own systems, the option to use only the integrated graphics processor is labeled as the option for "better battery life," so using a third-party tool to do this on systems that support automatic GPU switching will also help batteries. The only thing to keep in mind about third-party utilities is that Apple does not support them and in future OS updates there may be a bug or two with running the utilities.
- Reset hardware settings
Sometimes odd hardware settings can result in odd power usage by the system, especially after performing system upgrades like RAM and hard-drive replacements. To ensure these settings are set up properly, both reset the PRAM and the SMC on your system. Hardware resets will not harm your Mac, but may require you to adjust some settings again like the default system volume and mouse speeds.