The ultimate guide to save battery on Android

I mostly cover cell phone tracking apps, news and technology on this blog, but sometimes I also write on battery life as it’s the basis for all activities on any device. Without enough power, apps, GPS, WiFi and cell tower triangulation technology won’t work, not to mention to record your handset’s location continually. In a word, we all have to deal with this issue.

I say it’s a issue because most mobile devices won’t last a couple of days with the ever larger screen and stronger hardware. It’s a common fact that we need to charge our phone almost every one or two days even with a 3000 mAh battery inside. That’s why power saving tips can be found everywhere on the net and still we can’t get rid of the charger everyday, and the situation won’t improve until revolutionary battery technology comes out.

However, there are still a lot of things you can do to increase your battery life and I will show you how I doubled mine with many tweaks and tricks. You may find these tips elsewhere but a lot of time and effort are needed as they scattered everywhere, and some of them are even misinformation.

Some basics

We will start with some basics about what parts use up the most power on your Android handset so that we can take measures to tackle them. In general there are about six most power hungry parts in every modern smartphone, namely screen (include backlight), CPU, GPU, GPS, WiFi and 3G/4G model. To see for yourself, go to settings-> power saver-> battery use. You will see there how long your phone is on and how much power each item consumes. Not surprisingly, screen will top the list unless your handset in most time is idle. However for many devices you could not see the percent for things like CPU, GPU and WiFi etc. Well Android lists them in another way, it only shows those apps who use CPU, GPU and WiFi. For example, if you play games a lot, you will se the name of the game on the list. The same is true for WiFi and GPS. If you tap each item, you will see data like CPU total, CPU foreground etc. That data shows how much CPU cycle time that app uses. In-depth research about mobile phone power consumption can be found here.

Now that we figure out the most power hungry parts, I will introduce some major tweaks which can drastically increase your battery life.

Major tweaks and tips

1. Buy a phone with relatively smaller screen and bigger battery

If you don’t own an Android phone, or are planning on buying a new one, this tip is for you if battery life is of real concern. Otherwise, simply skip it.

Screen is the single most important power consuming part in every Android phone. Android devices tend to get ever larger screen. For example, Sony Z1 ultra has a startlingly 6.44” screen, HTC one max comes with a 5.9” screen, even the Galaxy S4 has a 5” 1920×1080 display. These phablets do deliver a superb experience, but at the cost of battery life as you have to lit up the screen whenever you use it. Just consider it, iPhone 5/5S only has half the battery capacity, yet delivers better battery life than many Android flagships. Apart from Apple’s great optimization, smaller screen is one of the most important reason behind the great battery life. Of course, display types count a lot too.

Another thing worths considering is the battery when deciding a cell phone. Although many Android handsets tend to have bigger screen, they are not quite progressive on battery capacity. To the best of my knowledge, only a couple of Android handsets have more than 3000 mAh battery.

It’s really hard to balance the battery and screen size when buy a phone since there are so many choices. Fortunately there are some websites conduct battery test and vote the devices with the longest battery life, which is a good reference.

2 Reduce the screen brightness

Dim your screen is another effective way to cut down the power consumption and it applies to any phone and any OS. Until you are in direct sunlight, it’s not necessary to maintain a very bright screen. Auto-brightness setting is always recommended. But it’s not so sensitive in some case, then you can disable it and go to the dimmest level that you can still read under without straining your eyes.

3. Underclock your CPU and GPU

High end Android devices now come with powerful hardware. While your device runs very fast, they also eat up your battery quickly. But if you underclock / undervolt it a bit, your device could still run much fast while save some significant amounts of power as well. For example, if you have a quad-core handset and the clock speed is 1.9G Hz, you can turn off two of them and lower the frequency to 1.2G. In this way your handset still runs fast and you can increase your battery life a lot. In fact some has doubled his battery life with undervolting. To downclock your device, try setCPU or kernel tuner.

If you have a phone which is very popular, there will be many custom kernels available. Some of those kernels will be more power efficient than your stock kernel and allows you to control your CPU and GPU clock speeds. This post has more information about the benefits and how to flash a custom kernel.

4. Proper apps management

One of the iOS’s advantages over Android is the numerous quality apps. On Android platform you probably have seen almost all apps auto start themselves, and lots of apps still run even if you exit them. The most irritating thing is that many apps prevent your handset from entering the sleeping mode even you lock the screen, this alone could drain your battery quickly. For example, your cell phone may drop 10% battery within an hour even you are doing nothing with it.

Once you root your phone, remove those pre-installed apps and bloatware from your handset (remember to backup). For those auto-start apps which you do need, I here would recommend two apps to deal with those apps and all of them needs root access. Autostarts and greenify. An Android app does not only start itself at startup, it could also run itself when you do certain things, like install an app, change the state of WiFi /3G, or change the time. The list goes on and on. Autostarts will list all those events under which an app would run and let you to decide whether toggle it on or off. If you disable all those events, an app will not be able to autorun itself again.

Greenify will do another important task for you. It won’t allow those apps continue to run once you hit home button. In android apps can run in the background if it creates a service, this is one thing Android device owners are proud of and we call it multi-tasking. While it can bring us many conveniences, our battery life will suffer. For example, when you exit an app (which means you do not need it to run now) but it still runs in the background and use CPU cycles to do things like push notifications, download ads and sync files etc. If you do not intend them to do so, it will waste your precious battery. Well Greenify would help fix that. It will list all those apps that could run in the background and eat up your battery and let you to decide. If you do not like them, greenify will stop them from running. But when you actually run those apps, greenify will give them green lights. In a word, it won’t affect your normal use.

5. Turn off auto-sync, GPS, WiFi, Bluetooth and 3G/4G while not in use

While these features give us great joy, they could also drain your battery very fast. If you do not use them, turn off them, only turn on when in use.

6. Always use WiFi over 3G/4G

Stay connected is important, but if both WiFi and 3G/4G network are available, go for WiFi. WiFi is more power efficient!! When I use WiFi, my battery drops 1% in about 4 minutes. But when I turn 3G on, the time is only 2 minutes. If you want to know more about the power consumption of WiFi over cell phone network connection, check this[gone] and this out.

7. Enable deep sleep

Generally, when you lock your screen, Android should cache all those apps in memory, turn off CPU, GPU and all those sensors and then go to sleep. However your baseband processor is still working so that you can receive calls and text messages. This is the most power efficient mode and Android provides a few choices. To enable this feature on your Qualcomm processor, open Root Explorer and go to /system, then open build.prop and search pm.sleep_mode, set the value to 1 (backup first!!). This property has four available values listed below.

pm.sleep_mode=0 -> Power Collapse Suspend
pm.sleep_mode=1 -> Power Collapse (Provides best power savings while sustain communication with your carrier’s network)
pm.sleep_mode=2 -> Apps Sleep
pm.sleep_mode=3 -> Slow Clock and Wait for Interrupt
pm.sleep_mode=4 -> Wait for Interrupt

As a side note, this tweak is debatable and seems it’s only available to Qualcomm processors. It also seems since Android 4.0 deep sleep is enabled by default, which means this property might be redundant.

However another thing about deep sleep absolutely needs your attention. Android system won’t go to deep sleep if any WAKE LOCK is detected. Both system and user apps can apply for WAKE LOCK and keep the system running even the app itself has nothing to do. I here would recommend using a free app called Wakelock Detector from the Google Play to find out which app holds what types of WAKE LOCK and use Greenify to monitor the bad apps or remove it completely.

Minor tweaks and tips

These tweaks would not increase your battery life significantly, but they will affect it to some extent. But you still need to pay attention to them as your overall battery life will improve.

1. Disable vibrations

Vibration or haptic feedback is more power consuming than ringtones. If you are not in a situation to use it like in a meeting, disable it.

2. Shorten Screen Timeout and front key light duration

Well I think there’s no need to explain that.

3. Do not power on/off frequently

Power on or reboot your device consumes more battery than normal use. If you do not use your phone in a while, just lock it. It also helps save your power button, lol.

4. Turn plane mode on when not in use

If there’s no signal coverage or the reception is very weak or you are going to sleep, then enable plane mode and it can save some battery. If you phone scan for signals from time to time, it will consume more battery.

5. Turn down WiFi scan interval

WiFi is truly more power efficient than 3G, but much more power is used when it searches for AP even you are associated with some one. Fortunately we can assign a longer time to it and dictate your device not to scan frequently.

Open Root Explorer or any other file browser and go to /system, open build.prop and search for wifi.supplicant_scan_interval, generally it’s giving a number less than 60 (seconds), you can change it to anything between 120 and 360. You will need to reboot your handset for the change to take effect.

6. Disable animations and do not use live wallpaper

These settings do make our mobile phone look great, but they also use more battery. If you really care about battery life, turn them off.

7. Use white wallpaper if you have LCD screen

White color tend to save more battery than others on LCD screen, but if your display type is LED (AMOLED for example), black is more power efficient.

8. Force GPU rendering

GPU does eat up more battery, but since Android Jelly Bean, it’s turned on by default. The thing is that some apps do not support GPU rendering yet, so Android provides us with an option to force use GPU to render our windows. It also makes our experience smoother and quicker, which will save us some battery juice. If you want to enable it, go to settings-> developer options.

9. Cool your phone

XDA developer Famar has created an app called Famarcool to cool your device. It does not downclock your CPU, but tweak your system and kernel to make your handset cooler. Just make sure WiFi connection is established when implement those changes and restart your handset (again backup first).

10. Do not use power saving apps

There are lots of power saving apps out there, but many won’t help you save any battery, on the contrary, they will use more power. Unless you are sure, don’t use them.

11. Do not use task killers

Why shouldn’t we use task killers? Then answer is quite simple, Android will manage the CPU and memory for you. When your handset needs more memory, Android will automatically kill apps not needed and release more memory. But if you kill those apps required by the system, your phone will restart it again, which results in reduced power efficiency.

You need to realize that unless an app starts a service or timer, it won’t use any CPU cycles once moved to the background (so it won’t waste your precious battery), it’s just cached in memory so next time it will be returned to its original state quickly when you run it, which is more power efficient. Now many Android phones come with 2GB of RAM, so there’s never any need to kill processes manually. If you do not need that app anymore, just remove it from your system.