As phones get more and more capable in this day and age, the trend has been for power requirements to far outweigh the advancement in battery technology and capacity. The unfortunate truth is that the smartphones of today are unable to hold a light to the simpler phone’s of yesteryear, at least in terms of battery life. This is a sad fact that many of us live with, at least until batteries improve. What if you don’t want to resort to extremes, such as carrying around spare batteries or a monstrous extra-capacity battery? iPhone users have long been finding ways to preserve the limited battery life, and iPhone OS doesn’t even support true multitasking (even with iOS4), hence you can see the problem we arrive at.
This series of articles will attempt to cover the common battery saving techniques used, many of which can be applied to other smartphones as well, not just Android devices. I will also input my own thoughts on the effectiveness and implementation of these techniques, as used on my Nexus One. With luck, it may also help you to achieve better battery life and enjoyment from your device. If these articles or tips help you, give a shout out!
There are three parts: 1) Beginner, 2) Intermediate and 3) Advanced. Please note a few things:
Note 1: Be realistic about your expectations of battery use. If you are thinking that some tweaks will improve your battery life from one day to one week like your Nokia 6110, then you’re aiming too high. You also need to decide how much compromise in connectivity you want to put up with (which will be detailed within). According to Google itself, you should be aiming for one day of battery life. If you’re not getting at least a full day, then something is very wrong.
Note 2: Instead of the commonly seen comments on various forums of: “I get one/two/three days of battery life with normal use, it’s great.”, which is useless to anybody else, a more quantitative method of measurement is a good idea to more accurately find any improvements. I highly recommend ‘Battery Graph‘, it’s simple, it’s configurable and it will show you exactly how much battery you’re using (commonly measured in % per hour).
Part 1) Beginner Tips:
Patch it up: Simple, but often effectively. Make sure your system software is up to date (this can be found in Settings / Check for System Updates), which will execute any OTA updates that are due. For example on the HTC Desire, there was a Calendar bug which caused undue CPU usage which has since been patched up. This also goes for programs installed on the phone, which can be updated via ‘Market => Downloads => Update’. Occasionally, developers will update their programs to be more efficient and have less drain on resources. This can have a noticeable effect if there is a messily coded program installed.
Monitor your usage: There is an in-built battery use tool in Android 2.1 and above. This can be found in ‘Settings => About Phone => Battery Use’. There are three things to look for here. First, if you actually use your phone at all, ‘Display’ will be the biggest drain on power, by a large factor. Secondly, if your reception is bad, your cell standby value will be affected. You can press on ‘Cell Standby’ to see the amount of time that the phone is frantically searching for a signal, as this drains battery, more on this later. Thirdly, if there are any specific apps which are drawing more than a few % of power, then this will show up on the list. By itself, it won’t save any power, but will give you an idea of what’s chewing your juice.
Tweak the display settings: As mentioned above, by far the biggest drain is the battery. I’ve noticed that this increases exponentially with the brightness of the screen. A maximum brightness screen uses substantially more power than twice a 50% brightness screen. Adjust the screen to the lowest comfortable level, or use the automatic dimmer (which errs on the cautious side). Some reports say that the light sensor used in the automatic dimmer (usually positioned above the screen) drains power in itself, but I have found no substantial difference either way. In addition, under ‘Display’ on Settings menu, you can adjust the display timeout. The key being the lowest convenient time you will be on one screen without doing anything. For me, I’m rarely on any screen more than 30 seconds (ie. reading a long web page), by that time I have scrolled, thereby resetting the timer. By reducing brightness of the screen and timeout, it’s easier on the eyes and you will have a major effect on saving battery.
Use the Power Control Bar: This is a very useful widget, as seen in Android 2.1 upwards. It allows for quick toggling of the different primary functions on the phone, including Wifi / Bluetooth / GPS / Auto-Sync and Brightness. Turn off things you are not using, the main ones being Wifi and Bluetooth, as these will scan for networks/devices intermittently. The GPS is fine to leave on, as it will only activate if you are running a program that uses GPS at that time. Since Android 2.2, the Brightness control now contains ‘Automatic’ in addition to ‘Low/Medium/High’. If you are using HTC Sense, there will be a different set of individual HTC widgets, as well as a ‘Mobile Data’ widget. This is equivalent to toggling ‘Wireless & Networks / Mobile Network / Data Enabled’, which will cut off all 2G/3G data. Also see my APNDroid write up. This can potentially have a large effect on battery use, I will go into detail later on about consistent data access.
Live Wallpapers / Wallpaper Choice: As nice as they look, once you have finished showing off the live interactive wallpapers to your friends, you should turn them off to save some battery. They take up valuable CPU cycles and serve little to no functional purpose. Turn them off, and switch to a static wallpaper. If you have a phone with an AMOLED screen (Samsung Android devices, Nexus One, HTC Desire), using a black background uses less power than a bright background. If you use an standard LCD screen, the opposite is true, white background. This has an incremental effect on battery life.
Widget Usage: One of the great benefits of Android is the ability to run live widgets on the home screens. This might include clocks, social feeds, news feeds, picture galleries and so on. These are great and occasionally very useful, however each widget does require a background service which uses a small amount of CPU cycles. In short, if you have a widget that is not absolutely necessary, then remove it. Chances are it only uses a tiny fraction of battery, but every bit helps. Perhaps assess if a standard shortcut would be better suited than a widget (shortcuts have no background services or CPU usage). This has an incremental effect on battery life.
Exit out of ‘some’ programs: Now this one is a bit tricky. The way that Android is structure, you should never have to actually ‘exit’ out of a program. Each program will suspend when it’s the background (unless explicitly directed otherwise), not taking up any CPU resources. If the phone runs out of memory, then suspended programs will be systematically killed behind the scenes, but saving their ‘state’ in the process. Once you re-run that program, it retrieves the state (for example, the exact location you were in a page or program) and it’s like it never happened. The official method to exit a program is to keep pressing ‘Back’ until you are back at the home screen, but this is very rarely necessary at all, due to the above reasons. However, there are two situations where programs violate this rule. The first is a badly made program. This is rare, but sometimes a program will continue to run in the background when it has no purpose to, taking up resources. Either that or it does exit cleanly. The second is if a program is explicitly designed to run in the background, such as a GPS program or Music Player, etc. By pressing Home, you are leaving it to run in the background, and this will drain the battery. If you have finished using the GPS program, press Back to return to the home screen, or select the ‘Quit/Exit’ option in the menu (if there is one). This will cleanly exit the program and return you to the home screen. This can have a incremental effect on battery life.
Check back soon for Part 2 of Android Battery Saving Tips – Part 2/3! If this has been of help, or if there’s any tips I’ve left out, please let me know and I will be happy to update.