Most smartphones are designed to give a typical user a typical day to a charge, with perhaps a small margin at the end. Unfortunately, many of us overuse our devices according to the typical benchmark used by manufacturers and we'll look to see if there are setting changes we can make to our devices in order to improve battery life. And unfortunately, we see the same battery saving tips touted time and time again giving very generic advice about how to extend battery life. Most of the classic advice was of limited benefit in 2010 and in 2015 can now widely be disregarded. Let's take a look at some of the myths that have lingered on over the years and pull the advice right up to date.
I'll start with the age old story about how it's good to discharge a smartphone battery before recharging it. The simple answer is that it isn't. Modern batteries can be charged or discharged as often as the customer wants. Older generation batteries - which have not been used in smartphones for fifteen years - suffered from a memory effect whereby they would "forget" they were partially charged if put back on a charger before being fully discharged. Modern batteries don't work like this. If anything, it causes more harm than frequent recharging as the deeper the discharge, the more heat that's put into the battery and heat is a battery killer.The golden rule of your smartphone's battery is: charge it when you need to. You don't need to regularly fully discharge the battery.
Another myth is that overnight charging kills the battery. This is incorrect. Smartphones contain charging circuits that dictate how much current is drawn from the charger and will prevent overcharging or overheating. When it comes to fast chargers and wireless (usually Qi) chargers, fast chargers may put a little more heat into the device and so may cause it to deteriorate quicker over the medium to longer term. Qi chargers definitely put more heat into the battery over a longer period of time so these may cause the battery to deteriorate quicker than under optimum conditions, but it is not clear what the difference is. And writing of chargers, providing the charger itself is a good enough quality, it doesn't matter what brand you use. The MicroUSB standard is just that, a standard. Smartphones will only draw as much current as they can cope with from your charger, so the charge is pulled from the wall socket rather than pushed into the device.
That's the charging hardware out of the way, now let's take a look at device settings and how we can optimize these and I'm going to start with how Android works with RAM and running applications. For the most part, applications are showing as running when in reality they are frozen and the image you see in the recent application view is a placeholder. When you jump back to the application, it will resume where you left off. Some applications do continue to run in the background but will complete the task that they have been given: the Google Chrome browser will continue to render a web page if you switch away but will suspend itself when it has finished.
As a user, we can manually close these applications in a number of ways. We can tap the back button on the application, use a close command, swipe it away from the multitasking view or use a task manager. It's usually not worth closing these applications because Android is optimized and efficient when it comes to multitasking and background applications from both a processor and RAM perspective. Don't be alarmed if your device seems to use all of its memory, because LINUX (Android's foundation) considered unused RAM to be wasted RAM and will use this space. If an application remains in RAM, this is kinder to the processor the next time you run it and this in turn saves battery. There are exceptions to this rule: some applications do run in the background and you will soon see these as they'll appear in your list of battery using applications. For these applications, it may be sensible to close them. But for everything else, you are wasting your finger swipes by clearing them.
The next point to consider is radio use and by this, I mean everything that your device may come with. Let's consider Internet radios (wireless data and WiFi), location services and everything else, including Bluetooth. Of these technologies, let's dismiss the "everything else" category first. These radios will use power when in use, and almost none when not. If you use these radios, then use them, but don't worry too much if you leave them active when you're done.
Things get a little bit more interesting when it comes to the internet radios on your device. Here, WiFi uses much less battery compared with mobile data, so if you have it, use it! Android can use the WiFi radio for location sensing, which I will come on to in a bit; you can set WiFi to always be in listen-only mode even when you have it turned off and for certain circumstances this can help battery life.
For mobile data, the golden rule here is: the faster the connection, the better the battery life. This works most of the time because modern chipsets are designed to work best in a "race to idle" scenario. This means that if you browse to a webpage, your modem will download the data and then drop to idle. There are some technical differences in the radios (basically, LTE is optimized for race to idle and 3G is less so) but modern devices usually show slightly better real world battery life when used over LTE compared with HSPA or 3G networks. The old rule of "disable 3G / 4G" is defunct, for not only will you grow old waiting for a modern smartphone to do anything over a 2G or EDGE network, but your screen and modem will be on for longer, sucking battery.
Google's location services is how the Android devices know where you are. Android takes information from the mast your device is connected to, visible WiFi networks and the GPS / GLONASS system in order to narrow down your location. Of these technologies, the GPS / GLONASS radio uses the most power but Android is well aware of this and will only use these radios if it otherwise cannot determine your location. Google Maps will, however, use these radios if you allow it! You can also use WiFi networks to boost location services and this works very well in an urban environment with plenty of WiFi hotspots, but in a field in the middle of nowhere it won't help. Using the mast your are connected to is the least accurate location sensor but uses the least power. However, enabling or disabling location services usually doesn't save much battery, depending on what you are doing with the device.
Unfortunately, the best advice for preserving your smartphone's battery life is to use it less, thus minimizing how long the screen is turned on. The networking tips above - stick with the fastest network available - will help you complete your task on the 'phone as quickly as possible, the sooner you can lock the device and shut the screen off. Other tricks are to disable those notification tones so that you don't pick up the device every few minutes to respond to a notification. Using a smartwatch can help your 'phone battery if you routinely check every notification but dismiss it without taking any action! Conversely, you can either disable the Internet connection,background data or AutoSync on your device, although this does defeat some of the point of having a smartphone!