The Definitive Android Battery Saving And Maintenance Guide

Don’t take it for granted that a smartphone’s battery can only last a couple of days. In this guide, I will show you how you can greatly extend the mileage you get out of your trusted sidekick. I’ve more-than-doubled the battery life of my Galaxy Note 3: my current record is 5 days, including quite a few phone calls and occasional browsing & gaming. True, the Note 3 has a large battery (3200 mAh compared to Galaxy S4 at 2800 mAh or iPhone 5s at 1560 mAh). If I’m conservative (which doesn’t mean that I don’t use the phone, but simply that I do not abuse the data connection), I can easily get 8 days out of it! I don’t think I have to tell you how awesome it is to reduce your reliance on recharging, not to mention this prolongs the lifetime of the device’s battery.

Many of the energy-saving measures presented here rely on one of the most capable automation apps ever: Tasker. There’s a gazillion things you can do with it, and one of these is the ability to regulate the way your device uses mobile data, which is a serious power guzzler. If you truly want some amazing battery life improvements and are willing to invest a few hours in permanently advancing the quality of your mobile experience, I’m going to remove your (potential) fear of rooting your device and also tell you about how to use a custom kernel for further energy saving.

And this is with 62 minutes of phone calls, mind you. Would you like to see something similar when you look at your battery stats? Read on!

And this is with 62 minutes of phone calls, mind you. Would you like to see something similar when you look at your battery stats? Read on!

The greatest strength of the Android platform is its openness. The ability to acquire full administrative privileges (root) on your device is a golden opportunity for fine-tuning your Android. Unlike in the world of Apple, you will not lose any privileges in Google’s Play Store. All updates will continue to work just fine and you are not breaking any law. It’s your device, do what you wish with it!

The amount of extra battery hours you will earn after going through this guide is entirely dependent on how many of the tweaks presented here you will apply. Another determining factor is reducing your reliance on mobile data. Do you really need your gadget to be permanently connected or can you live with a 5-10 minutes delay in E-mail or FaceBook notifications?

Battery Maintenance

Before we talk about software, let’s mind the hardware a bit. Most Android devices are powered by a lithium-ion or lithium-polymer accumulator. Such batteries have a limited number of recharge cycles before they become almost useless. With every recharge, a bit of the accumulator’s capacity is lost. Maybe you can see where I’m going with this: the more power you waste, the sooner the battery’s lifetime shrinks to an annoyingly short sliver.

There’s more: many people don’t even wait for the remaining energy in the accumulator to drop below 40% before recharging it (which is understandable if you can’t even make it through the day with a battery at 40% – that is until you finish reading this guide, which may very well change things for you). Even though lithium accumulators do not have the “memory effect” of the NiMh/NiCd technologies, toying with recharging is a sure way of degrading the material inside the battery.

The ideal period to recharge is between 20% and 30%. Allowing the power levels in the accumulator drop under 20% is also not recommended: lithium accumulators should not be fully discharged; try to stay away from the 10% threshold. I did go there a few times just to see how much I could get out of it, but that was only for the sake of science :). Also: you do not need to charge up to 100%. Ideally you will unplug between 90 and 100% (although this is not as important as not allowing the battery to completely lose its charge).

Soon, it would be a good time to recharge your gizmo.

Soon, it would be a good time to recharge.

With the exception of constantly playing games or watching movies (or other processor & screen intensive applications), following this guide will surely improve the number of hours you can use your Android before having to recharge it. This means that you won’t have to recharge early (when you’re at 40-50%), but rather wait until it gets down to 10-20% and this, in turn, means that the lifetime of your device will be prolonged.

That being said, I will now go through several applications which you can use in the quest for taking control of your gadget. I will carefully explain how and when to use them and estimate the impact each of these tools has. So, buckle up, because this is going to be a long and hopefully fascinating ride!

Velis Auto Brightness (free)

We will start with an app (Google Play^) which is not only free, but does not require a rooted device either. The light sensor is ubiquitous in all mobile devices sold today, but the software handling it is not very bright (pun intended). As a matter of fact, this is the case with most “stock” software. Luckily, there are great programmers out there who are good at listening to what the hardware whispers and put this information to better use.

The screen is usually one of the heftiest consumers in any mobile device. Before using a proper auto-brightness tool, I was forced to keep my brightness at a rather high level and this impacted the battery life quite a bit. I would say that I’m getting an extra 10% battery time by using Velis.

What I found very nice about this tool is that it can exclude certain applications from brightness control. I like the Camera, Gallery and the games I play to all run at maximum brightness and Velis does an excellent job in allowing that. It’s also cool that you can see the readings from your light sensor represented on the luminosity control graph in real-time (and translated into actual screen brightness setting).

You can also define custom profiles by specifying brightness points in the graph by dragging the thick “handles” of the two axes. It’s not the most user friendly system, but it works. Just remember this: customize your graph first and only after that can you tap on “New Profile” and save it with a certain name. As you can see, I have a battery-friendly profile but also a high brightness profile. The “Sudden” profile has a very quick transition to very bright when I’m out in the sun.

Velis Auto Brightness. Left: Graph Editor. Right: Excluded Applications.

Velis Auto Brightness. Left: Graph Editor (Battery Profile). Right: Excluded Applications.

Velis has a lot of other options which I will not go into detail about; the ones you will really need are quite self-explanatory. There are other brightness control apps out there as well, but according to several people and my own investigations, this one is the best (not to mention it also has a Tasker plugin, which allows you to switch profiles automatically when various events happen – this can also be used to create per-application profiles, a functionality that Velis lacks).

Tasker (paid ~3 Euro)

Now it’s time to bring out the heavy guns: I estimate that Tasker (Google Play^) is responsible for about 75% of the power I’m saving daily! You can use this application to optimize energy use in (at least) two ways: regulate mobile data consumption (does not require root) and automatically switch your device to Airplane Mode whenever you’re sure you don’t need to be contacted (requires root).

Let’s first have a look at how you can optimize data consumption, since this doesn’t require rooting your device. The reason why I use Tasker for this, rather than trust the sync settings of various applications, is because (and there’s no way to sugar-coat this) most apps are very poorly (or maliciously) written and even if they don’t do a lot of data transfer, they still wake up the phone’s radio which translates into a lot of lost energy! This issue drove me mad a few months ago when I saw that about 30% of my phone’s sleep time was wasted by data wakelocks due to a poorly written update service.

What I do with Tasker (and I will show you precisely how this is done) is quite simple: when the screen’s off, I don’t need my phone to check for anything, therefore mobile data is disabled. Optionally, you can tell Tasker to turn on mobile data every 10 minutes for 30 seconds: that way, you save energy while in the same time receiving your notifications. Tweak as you wish!

First of all, we will create two Tasks: one that turns mobile data on, and another that turns it off.  To create a new Task, you tap the + button in the lower right part of the Tasks tab. Name your Tasks “Data On” and “Data Off”. Once you create the first Task, tap it and you will be taken to a screen where you can (again) tap the + button at the bottom of the screen to create an Action. You will be presented with a choice of Actions. It’s enough to filter by “mob” and you’ll already be able to easily pick out the “Mobile Data” Action. Then, you set it to “On” or “Off” based on the Task which you’re now creating.

Creating a Tasker Action.

Creating a Tasker Action.

If you found any of this a bit too complicated, I recommend you to read my in-depth Tasker article^, which shows all my battery-saving Tasks and Profiles and explains things in more detail.

Now, we need to create two Profiles: one triggered at Event “Display On” and another at “Display Off”. Tasker organizes its automation magic in Profiles. Profiles get triggered by various Events (chosen when you create the Profile). When an Event happens, the Tasks which are associated with the Profile are executed.

To create a new Profile, you tap the + button in the lower right of the Profiles tab. Pick Event and search for “dis”. Now you can pick “Display On” or “Display Off”. As soon as you pick the Event, you’ll see a list of Tasks. There, you can pick the appropriate Task for the Profile you’re creating. Create one Profile for “Display On” and another one for “Display Off”. You then link the Tasks to the Profiles and you’re all set. I exemplified below.

Creating a Tasker Profile.

Creating a Tasker Profile.

My Tasker profiles are a bit more complex. Those “Display Off” and “Display On” Tasks that you see up there actually do quite a bit more than just turn mobile data on or off. I do not want mobile data to be activated immediately when I switch on the screen, since some applications that rely on data will automatically start-up when this happens. Because sometimes I only turn the screen on for a few seconds, there’s no point for these apps to be called into action. This is why my Tasker waits for 20 seconds before enabling data connectivity.

But wait, there’s more. What if I want to start browsing immediately after I turn on the screen? Well, there’s a nice Tasker Event which fires when a certain application is started. You guessed it: when I start my browser, data is instantly turned on. On the contrary, there are times when I turn the screen on just to take some notes, which is why I have a “Cancel Data Start Once” Task which gets triggered when I start text-editing or playing games. As the name implies, this only happens once. As soon as I need data, it will be enabled. I almost never have to tinker with mobile data settings manually. It is all handled by Tasker. An added benefit of handling connectivity so thoroughly is that you might reduce your carrier charges.

Application-based Tasker Profiles.

Application-based Tasker Profiles.

I’ve shown you some screenshots of my profiles, but this is barely scratching the surface. I don’t want to clog up this article with too much detailed information, so if you want to learn more, read the full article^ covering my Tasker profiles. There, you will learn enough about this application to use it for many other things as well.

Some of the powers of Tasker include being able to do things whenever you are close to a WiFi network or whenever you are in a certain location (it uses the GPS to determine that). It can react to any of your phone’s sensors (humidity, temperature, magnetic) and work its magic in all sorts of scenarios.

Root Time!

We shall now confront the elephant in the room. Aside from a few other small tweaks, you can’t do much more regarding your Android’s battery life until you root it. This will unlock the awesome power of automagically handling Airplane Mode and many, many other things. Rooting your phone is quite easy if you have a bit of patience and are willing to invest a few hours in this.

There is a ton of information about how to do it and the only thing you need is an USB cable and perhaps a Micro-SD card. The best place to start is XDA Developers^, the largest and oldest “phone tinkering community”. I linked you the Top Devices section of the Forum but if you don’t find your gadget there, go to “All” (beware, it might seriously bog-down your browser). And of course, always do some Google searches as well. More often than not, a guide has already been written about how to root your exact model!

Rooting is a procedure that varies from device to device, but I will share with you the important information which is common in all scenarios. Before rooting, make sure you backed everything up, as the procedure will completely destroy every shred of personal data on your gizmo. Secondly, make sure you found a good online trove of information pertaining to your exact model. My Galaxy Note 3 for example has three different models based on the region it is sold in; mine is N9005 and I have a ROM which was built specifically for my model.

Go to "About Device" in "System Settings" to find your phone's model number.

Find your phone’s model in “About Device” in “System Settings”.

Check your model number and make sure you find the correct ROM (which contains the Android Operating System) for it. Read carefully, exercise patience and ask when not sure. Rooting is simple but not without risks. Don’t stress out, take it slowly and wait until you have all the information.

Also, it is true that you might lose your warranty when you root your Android, depending on the place of purchase and manufacturer. Most devices can be un-rooted quite easily (the process is similar to rooting), but there are some, such as my Galaxy Note 3, where rooting is a one-way ticket. But that didn’t stop me: I’ve rooted it one hour after I got it and getting rid of the bloatware which usually comes from all manufacturers/carriers is the smartest thing one can do to a device – it’s like curing it of cancer or exorcising the demons out of it.

The risk for security breaches does not increase on a rooted phone, but the damage a security breach might lead to, does, since a malicious program could grab root access. However, as long as you are careful about what apps you install and you use a proper browser (Chrome or FireFox), not visiting shady websites, you will be safe. My Android phones have never been infected, without ever using any kind of software protection.

One other thing to keep in mind is that if your device is locked in the network of a certain carrier, you might have to search for ROMs for that specific carrier, or unlock the device. In some cases, you can find software applications which can unlock a phone and then you can use any kind of ROM made for your device. Large carriers make such ROMs available via their websites. That’s how the smart wizards from XDA Developers can give you a better mobile experience: they remove bloatware from a manufacturer or carrier-provided ROM.

Are you afraid now that you’ve read all this? Don’t be! I’ve made many mistakes while rooting my phones (I’m at my 3rd root now and even this time I messed up at least twice). There is almost always a way to recover the device if you screw something up. If it is equipped with a memory card slot, it is quite useful to have one such card available and be able to transfer files to it without the assistance of the device (use the PC and an USB adapter). This saved me from a headache during the last two root operations I went through: I made a mistake and couldn’t use the USB to flash my new ROM, so then I put in my memory card and I transferred the files using that way (otherwise, I would’ve been obligated to un-root it and restart the entire process).

ClockworkMod and Odin are two very popular rooting tools. Odin is used by Samsung devices.

ClockworkMod and Odin are two popular rooting tools. Odin is used by Samsung devices.

It is important to keep in mind that once you’ve rooted your phone, you have access to some excellent backup tools that can restore your entire application library, plus all personal data. This way, you will be able to try various ROMs and kernels without any risk. One of the most famous and perhaps the best backup tool is Nandroid Manager (Google Play^). First, you create a backup with ClockworkMod or TWRP, and then Nandroid Manager allows you to explore or restore it. You can selectively extract whatever you wish from your backup.

Nandroid Manager is a great backup tool.

Nandroid Manager is a great backup tool.

One more thing: rooting is free. Any tool that asks for money can be considered highly suspicious. Odin, ClockworkMod and TWRP are all free. So are the ROMs which you can find online. Some services will ask you for money to achieve faster speeds when downloading the large ROMs (~1 GB). Do not pay: there is always a “free download” button. It might take 2 hours but it’s definitely not worth it to spend your money there, unless you have lots of it and wish to support their servers. I prefer donating directly to the developers and I do that often.

Speaking of developers: I can highly recommend that you install one of the popular custom ROMs (which contain tweaked Android OSes). For example, on my Note 3, I installed the Omega ROM^, which is based on a stock Samsung ROM but comes with a ton of improvements, ability to remove bloatware at install-time and, most importantly, a custom, light-weight kernel, to reduce battery consumption. Of course, the ROM I linked above works only on the N9005 Note 3, but if your device is mainstream enough (in 90% of the cases, it is), you can surely find something for it.

Super SU (free but has “pro” version, requires root)

Now that you’ve hopefully rooted your phone, it’s time to set up two applications which are essential for what we’ll do onwards. Super SU (Google Play^) helps you regulate other applications’ access to root privileges. Be advised that most ROMs that you will install after rooting already have Super SU in them, unless you went for a stock ROM (directly from a manufacturer/carrier) in which case you will have to install it yourself.

This is my list of applications in Super SU. You can also see what it looks like when an app asks for permissions.

List of applications in Super SU and also how it looks when an app asks for root access.

The PRO version of Super SU (which I purchased because I believe in supporting the developers) has logging support and a few other nice features which I don’t use :D (the free version should be good enough for everybody).

Secure Settings (free but has “pro” version, requires root)

Before we return to Tasker, you will need to install this nifty little app (Google Play^). It has a plugin which allows Tasker to control the Airplane Mode of your phone, something that is very important for energy saving.

Once you install it, you need to enable the System+ Module from inside the application. Super SU (which you installed earlier) will ask you if you wish to allow Secure Settings root access. Allow it and tell Super SU to remember the choice.

Secure Settings is a central piece of the battery saving process.

Secure Settings is a central piece of the battery saving process.

The PRO version of Secure Settings allows access to many other root-only behaviors. Airplane Mode, however, is in the free version. I only needed that but I still bought the pro version; the reason, you already know.

Tasker (part 2)

Now let’s go back to having some good ol’ Tasker fun by teaching your gadget to automatically go into Airplane Mode! First of all, you have to create two new Tasks. After you create a Task (something you already know how to do), when you add your Action, instead of searching for “airplane”, you have to search for “secure” or “sec”. The Secure Settings plugin will stand out; choose it.

You will now be taken into the Secure Settings Action edit screen. In the Configuration section, tap on the pencil icon to tell Secure Settings what you wish it to do. You should now be in Secure Settings’ own Action selection process. Expand the “Root Actions” section and pick “Airplane Mode”. In one Task you have to enable it and in the other Task you disable it.

Creating the Airplane Mode Action.

Creating the Airplane Mode Action.

Now, to make it all work, you should create at least two Profiles. These will tell Tasker when you wish your device to go Airplane and when it should get connected with the rest of the world (assuming the NSA doesn’t have something to say about that^). When creating the new Profile and prompted for the type of Event that should trigger it, you will probably want to go for Time. You will then be allowed to pick the time at which you want your device to go into that Profile. Finally, you select one of the Airplane Mode Tasks which you created earlier.

And voila, your just saved roughly 30% daily pointless cellular connection, not to mention there’s less radiation going on now! This simple action is responsible for 15-30% extra battery life! Again, if you’re not finding yourself comfortable with Tasker (it’s not the most user-friendly program in the world), check the other guide^ I wrote. It explains how to do all this in more detail.

Better Battery Stats (free, recommended to have root)

Now, it’s time to home-in on any evil applications that are draining your accumulator. There is a vast array of tools at our disposal, but I have picked what I considered are the best three. The amount of extra battery time you will gain by using these apps is hard to estimate: it depends entirely on how bloated your gadget is and how thoroughly you clean it up.

Better Battery Stats (Google Play^) will show you exactly how much time your device spends in deep sleep, awake, screen on and, most importantly, you will find out if there are services which abuse your Android’s wakelock.

Better Battery Stats is a very useful monitoring application.

Better Battery Stats is a very useful monitoring app.

You’ve heard this “wakelock” word a few times by now. What does it mean? Wakelocks are what keep your device from going into deep sleep. Of course, wakelocks are most often required, but it sometimes happens that some poorly-coded application abuses this feature and you get a device which instead of going into deep sleep for 95% of the time the screen is off, does it only 50% of the time. This means that the phone’s processor will drain your battery, most probably for no good reason. When you spot something strange, Google it and find out more about it.

Wakelock Detector (free but can be supported, requires root)

And in comes the Sherlock Holmes of wakelock sniffing (Google Play^)! Better Battery Stats is useful for identifying things that go wrong and show you exactly how serious a problem can be, but Wakelock Detector is more specific and offers a better representation of the data it gathers. The application is free but you can purchase extra features for it.

Another very useful monitoring tool.

Another very useful monitoring tool.

Don’t get alarmed if you see Tasker having a ton of wakelocks – there’s nothing to be afraid of and as you can see, the total time is tiny. You can also probably ignore the Clock and other trusted applications. I’m going to assume that you’ll realize when you see something fishy going on.

I would recommend installing a fresh ROM and writing down its usual wakelock-generators and only after a few days, start installing stuff. This way, you will increase your chances of noticing when something is afoot. And of course, there’s always the XDA Developers Forum and Google which can clear your doubts.

Disable Service (free but can be supported, requires root)

This is another gem in the wild (Google Play^). Once you identify an offending application, you can use this tool to investigate things further: see what services are running and perhaps disable some of them. Of course, you can turn services back on whenever you wish or need.

A word of advice: if something starts malfunctioning on your device, do try to consider that it might be caused by a service you disabled. I once killed the Fused Location Service (from Google Play Services) and scratched my head for about two weeks as to why Google Maps doesn’t work anymore :D. You can easily find which apps have services disabled by using the sort button.

You can use Disable Service not only to monitor but also shut down bloatware.

You can use Disable Service not only to monitor but also to shut down bloatware.

Android App Manager (free)

All Android devices have an App Manager. It can usually be reached by touching your phone’s Options button (the one on the left) while in the Home screen. You should see “Manage apps” right there along with “System Settings”. If you don’t, then just go to your gadget’s Settings and search for Application Manager.

The cool thing about this is that it’s available on any Android and it has a tab called “Running”. Here, you can see all the running applications and services. This has been very useful to me, actually, even while writing this article.

I was experiencing a mysterious battery drain. In spite of my fine-tuning, all of the sudden, my Note 3 started losing almost 1% of its battery every hour, even with the screen off and no data, something I found unacceptable. I used the App Manager to discover that DropBox and Spotify had some services running, services which I did not require (as if I needed further proof of how annoying some applications can be). Once I shut them down (which can be done straight from this tool), the phone went straight back to its usual consumption. Soon, I’m going to start investigating which one of these two was the actual culprit and save it for an article where I’ll shame the developers of such crappy applications.

App Manager is available on any Android device.

App Manager is available on any Android device.

Advanced Task Killer (free but can be supported to remove ads)

Task Killers were highly popular a few years ago, but they got quite a bit of bad publicity mostly due to two factors. First of all, there are way too many task-killing applications out there and this includes a lot of poorly written ones. But most importantly, they are misused. I’m using Advanced Task Killer Pro (Google Play^) for regular 1-hour process cleanups. This is achieved by having a “Safe Auto-kill” frequency of 1 hour.

The important thing to understand here is that if processes which you use a lot are killed often, then the device’s processor will have to load them back in memory again and again, thus wasting energy. Some applications can’t even be killed. For example Tasker and Velis Auto Brightness have to be constantly running. To that end, fortunately, Advanced Task Killer has an ignore list.

You can set the Advanced Task Killer to display more of the device’s processes, but be aware that this might lead to killing essential services which may hurt your gadget’s stability. Therefore make sure you add all your well-behaved or essential applications and services to the ignore list. I would advise you to never ignore apps which use data such as FaceBook, Spotify, DropBox, Chrome and so on. If it’s something that connects to the outside world, let the Task Killer whack it when you don’t need it.

One of the best task killers out there.

One of the best task killers out there.

Custom Kernel (free)

Last but not least, having a custom kernel can be very beneficial to your gizmo. Using such a kernel, you can under-volt and under-clock the device’s processor, which is just about as hardcore as you can get in this business of energy saving. Usually done in the range of 50 millivolts / 500 MHz, this technique will lead to the processor consuming less current. Done in small measures, under-volting does not hurt your Android’s stability; however, it will perform slightly slower (due to the reduced processor frequency that comes in the package). I’m more than happy to do this to my Note 3 since I consider its processor to be overkill anyway.

There are lots of custom kernels out there which can do this; you just need to search for a bit. I do not recommend doing the opposite (over-clocking), as this may damage your processor. Under-clocking cannot usually do damage, even if you exaggerate with it. Worst thing that can happen is that your device will become unstable and sometimes crash, in which case you can always use the recovery (ClockworkMod or TWRP) to restore the kernel to its default state without having to lose any of your data.

To Conclude…

Achieving a firm grip on your device’s data consumption patterns and way of functioning is not as hard as it might seem. All you need is a bit of patience and the willingness to sit down and carefully read some quite simple information, then apply it. Given the trove of knowledge available online, even a newbie can root an Android and this is a highly recommended thing to do, as it opens the door to major benefits (you can do many awesome things with a rooted gadget, much more than just tweaking battery consumption).

I truly hope that this guide will have been of use to you. If it was, feel free to post some results and impressions in the comments section. Most importantly, share the guide with anybody you think might find it useful.

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    • Reply

      Awesome! Especially the 1st one! Thanks for the tip! Will look at them and update the article as necessary! Sorry, I didn’t mean to scream! I’m just a bit tired and enthusiastic about the apps!

    • Reply

      Correct. This is why I said that “under 30% is a good time to recharge”, not “under 10%” like I did in the article’s image. The reason I did that was to show exactly how much time I got out of it :). Your comment is very valuable however and I should specify it more clearly in the article. Thank you. I shall update.

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