Android battery life and the tools for monitoring usage have gotten better over the last few years, but the stock options are still sometimes not enough. But there are ways to gauge your battery usage, remaining time, and even hunt down apps that steal your precious juice.

RELATED: Why You Shouldn't Use a Task Killer On Android

Before we get into the details, though, let’s talk about one thing you shouldn’t do to your battery. We’ve all seen those awful “optimization” apps that promise to improve battery life, but you should stay far away from those. Basically, they operate under the old-school thinking that background apps are chewing through your battery, so they just kill them. That’s really a terrible idea, because these apps are effectively just glorified task killers. And no one should ever use a task killer on Android. Ever.

Now, with that out of the way, let’s dig in to how to really get a better idea of what’s going on with your battery, and what you can do about it when something goes wrong.

Check Your Active CPU Frequencies with System Monitor

System Monitor (free, Pro) is one of my favorite apps for, um, monitoring Android’s system. While it can do a lot of different things, we’re just focusing on one today: keeping an eye on CPU frequencies. This watches the processor’s most-used frequency states—1.2GHz, 384MHz, etc.—and then tracks how much of the time the CPU spends in each state.

For example, if your phone has been lying on your desk for four hours with very little use, you want the top CPU state to be “Deep Sleep,” which means everything is working like it should be—there are no apps keeping the processor alive and draining the battery. But if you’ve been playing a game for the last hour, the top state may be something like 1.5GHz, because it’s more taxing on the processor.

The point is this: knowing what the processor is doing in the background can give you a lot of insight into what’s going on with your battery. If you haven’t been using your phone and the top process isn’t “Deep Sleep,” then something is going on in the background and you’ll need to figure out what it is.

The good news is that System Monitor can kind of help with that, too (though there are better apps for the job, and we’ll discuss them later). One swipe to the right of the CPU Frequencies tab is the “Top Apps” view, which shows you what apps are most active in real time. The top app is always System Monitor itself, because it’s the foreground app. It’s the stuff bouncing around beneath it that you’ll want to take a closer look at.

To keep an eye on what’s going on with CPU Frequencies, I highly recommend using its widget. I always drop it on one of my home screen pages for a quick look at what’s going on—you know, just in case. The only thing worth noting here is that it doesn’t always stay active and up to date, so sometimes you need to cycle through the various states by tapping the widget and forcing it to update.

Anticipate Remaining Time and Find Trouble-Causing Apps with AccuBattery

While Android does its best to estimate how much battery you have remaining, this number can vary wildly depending on what you’re doing. That’s where a slightly more scientific approach comes into play, and a third party app called AccuBattery does the trick better than most others.

RELATED: How to Monitor Your Android Device's Battery Health

AccuBattery offers quick, detailed information about your battery in a handy notification that includes current time left (estimated, of course),  discharge rate, and how much battery is consumed (in mAh) with the screen off and on. The latter also includes the percentage of battery use per hour. Like I said, it’s a lot of information in a very compact package.

But AccuBattery’s usefulness doesn’t end with a simple widget. Its “Discharging” page is chock-full of great info when it comes to breaking down where your battery life is being spent. The page is separated into various subsections, where you’ll find specific info like this:

  • Battery Usage: Screen on time and mAh used; Screen off time and mAh used; Per-app usage in mAh; Deep Sleep time, including the percentage of screen off time
  • Discharge Speed: Screen on discharge rate (hourly); Screen off discharge rate (hourly); Combined use; and current battery consumption in mAh
  • Foreground Battery App Usage: Find which apps are using the most battery while running in the foreground
  • Average Battery Usage: Screen on, screen on, and combined use details over time
  • Full Battery Estimates: How long your battery will last on a full charge for screen on, screen of, and combined use

This is an exceptionally easy way to break down where your battery life is going, with various metrics (percentage and mAh) to make it easier to read and understand. On top of that, you can see which apps use the most battery, though you’ll have to use a bit of deductive reasoning here. If the app you use most is at the top, that’s probably correct. But if the app at the top is one you rarely use, that’s an issue you need to investigate further.

Aside from discharging details, you can also find out more information on your battery health. While we have a full guide that covers how to use AccuBattery to determine your device’s battery health, here’s the gist. The longer you use your phone with AccuBattery installed, the more accurate it gets. It takes time to determine health stats, so after you install the app, just use your phone like you normally would. AccuBattery runs in the background, calculating current charge and discharge rates, as well as battery wear, capacity, and overall health.

When it comes down to it, AccuBattery is my personal favorite battery utility. There are others on the Play Store (and I’ve tried a lot), but I find AccuBattery to have the best info in the easiest-to-use-package. The meat and potatoes of the app are found in its free package, but you can get more out of it with the $3.99 Pro app.

Get Even More Info with a Rooted Device and Better Battery Stats

Both of the apps we’ve talked about so far are excellent tools on their own, but both also offer more advanced features for rooted users. Tools like GSam Battery Monitor can provide more advanced usage details, like wakelock and sensor usage, and System Monitor itself can provide access to app cache. While the latter doesn’t necessarily help with battery life, it can at least help clear up some space on your phone.

There’s also an app named Better Battery Stats that essentially relies on root access to provide its information. If you’re running a rooted handset, it’s an incredibly valuable tool. It lets you get a detailed look at what’s happening behind the scenes, including app usage and wakelocks, with the ability to find changes in behavior quickly so rogue apps running in the background can be dealt with as soon as possible.

While the other apps we’ve talked about in this article are fairly straightforward and easy to understand, Better Battery Stats is definitely for more advanced users. It covers battery use at the system-level—things like partial and kernel wakelocks. It requires a slightly deeper knowledge of Android in order for it be as valuable as it can be, but if you’re rooted and looking for a way to know essentially everything possible about your battery, this is it.

With the right tools, managing Android’s battery can be simple. Finding battery-draining rogue apps can be a quick and painless process if you know exactly where to look, and with the apps in this post, you’ll be armed for the job.

Profile Photo for Cameron Summerson Cameron Summerson
Cameron Summerson is ex-Editor-in-Chief of Review Geek and served as an Editorial Advisor for How-To Geek and LifeSavvy. He covered technology for a decade and wrote over 4,000 articles and hundreds of product reviews in that time. He’s been published in print magazines and quoted as a smartphone expert in the New York Times.
Read Full Bio »