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How to calibrate the battery on your Android phone or tablet

Battery problems are among the biggest concerns for smartphone users, which is why we offer so many useful tips for solving battery drain issues. If you notice that your battery performance and duration has decreased, it could be time to calibrate your battery.

Jump to section:

How do I know whether my battery is the problem?

First of all, you need to identify why your battery performance has decreased: is it the Android system's calibration or the battery itself? We'll move onto calibration in the sections below, but you should check if your battery itself is damaged first. 

If your phone has a removable battery cover, turn off your phone, remove the cover and inspect the battery. Look for bulges or leaks. In the image below, you'll see what a normal battery looks like next to a swollen one. If your phone doesn't sit flat on the table anymore, that could also be a sign of a swollen battery too.

AndroidPIT Smartphone Overheating 2583
A swollen battery is easy to spot. / © ANDROIDPIT

Should I calibrate the battery?

If you're satisfied that the battery itself is not the problem, you can move on to the steps below. If you think your battery might be the problem (even after trying to recalibrate it), we'd advise you to take it to a repair shop for an expert's opinion. If it turns out you need to replace the battery, go with an original or reliable third-party battery. Scrimping on a cheap knock-off battery only leads to more headaches in the long run.

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Keep in mind that there are plenty of other things that can cause a battery to malfunction. If your phone doesn't charge, there might be a problem with the port, so check our guide on what to do when a phone won't charge.

If you've just updated the firmware on your phone, battery drain is a common complaint, so you might want to clear the cache partition on your device. Thankfully, we have plenty of guides on how to clear the cache on various devices.

AndroidPIT Nexus 5 Android 6 0 Marshmallow problems 1
It's a good idea to be familiar with what's normal for your battery. / © ANDROIDPIT

What is calibrating a battery?

The Android operating system has a feature called Battery Stats, which keeps track of battery capacity, when it is full or empty. The problem is that it sometimes becomes corrupted and starts displaying data that isn’t real, which, for example, causes the phone to turn off before it reaches 0 percent. Calibrating your Android battery simply means getting the Android OS to correct this information so it is reflective of your actual battery levels once again.

It's important to understand that you can't actually calibrate the battery itself: it is, after all, just a cell that stores power and discharges. However, lithium-ion batteries do include a printed circuit board (PCB), which serves as a protection switch to stop them exploding or deep discharging.

ANDROIDPIT battery 1
Although some batteries can explode, it is rare. / © ANDROIDPIT

Smartphone battery myths

Lithium-ion batteries don't have a memory so there's not much you need to do to keep them running as they should. The problem lies with how the Android system reads and displays the current capacity of the battery, not the battery itself. 

The same goes for the myth that deleting the batterystats.bin file will magically recalibrate your battery. That file (on most devices anyway) simply stores data about what is using the battery when it is not being charged. It is also reset every time a battery is charged to over 80 percent and then disconnected from the charger.

The batterystats.bin file contains the info you see made prettier in the Battery section of your phone: it's the Android system keeping track of your battery's usage, per charge cycle. When we talk about battery calibration, it's the percentage meter that gets out of whack, and that is what we need to fix. 

androidpit battery low 1
If your battery indicator is out of whack, you should try to recalibrate it. / © ANDROIDPIT

How to calibrate an Android device battery without root access

The old 'fully charge and discharge' approach stands as one of the simplest ways to 'recalibrate' your Android battery. We've warned you in the past about low voltage problems in lithium batteries and the negative impacts of fully draining a battery on its lifespan and the same holds true here. But, if your phone battery is causing you real problems, it's worth taking the risk.

Method 1

1. Discharge your phone fully until it turns itself off.

2. Turn it on again and let it turn itself off.

3. Plug your phone into a charger and, without turning it on, let it charge until the on-screen or LED indicator says 100 percent.

4. Unplug your charger.

5. Turn your phone on. It's likely that the battery indicator won't say 100 percent, so plug the charger back in (leave your phone on) and continue charging until it says 100 percent on-screen as well.

6. Unplug your phone and restart it. If it doesn't say 100 percent, plug the charger back in until it says 100 percent on screen.

7. Repeat this cycle until it says 100 percent (or as close as you think it's going to get) when you start it up without it being plugged in.

8. Now, let your battery discharge all the way down to 0 percent and let your phone turn off again.

9. Fully charge the battery one more time without interruption and you should have reset the Android system's battery percentage.

Remember that it is not recommended to perform this process regularly. Even when your battery is so dead your phone won't even turn on, your battery still has enough reserve charge to avoid system damage. But you don't want to poke the tiger with a stick. Perform this process once every three months at the most. If it is required more often than that, you have bigger problems at hand.

Put plainly: fully discharging a battery is bad for it. Trying to overload a battery is also bad for it. The good news is that charging batteries will shut off automatically when they've reached their safe limit and there's always a little in reserve even if your phone won't start. Again: only do this when really necessary, because it does have a negative impact on battery life.

AndroidPIT Galaxy S6 Ping Pong Root
If your phone has root access you can clear the batterystats.bin file. / © AndroidPIT

How to calibrate an Android device battery with root access

Even though I'm not convinced that clearing the batterystats.bin file has any meaningful effect on how the Android system reports remaining battery charge, there are those who swear by this method.

So in the interest of fairness, we've included the process for you here (it is true that different manufacturers use the batterystats.bin file for different things). It's basically the same process as above, but with the added step of using a root-enabled app.

Method 2

1. Discharge your phone fully until it turns itself off.

2. Turn it on and let it turn off again.

3. Plug your phone into a charger and, without turning it on, let it charge until the on-screen or LED indicator says 100 percent.

4. Unplug your charger.

5. Turn your phone on. It's likely that the battery indicator won't say 100 percent, so plug the charger back in (leave your phone on) and continue charging until it says 100 percent on the screen as well.

6. Unplug your phone and restart it. If it doesn't say 100 percent, plug the charger back in until it says 100 percent on screen.

7. You want to repeat this cycle until it says 100 percent (or as close as you think it's going to get) when you start it up without it being plugged in.

8. Now, install the Battery Calibration app, and before you launch it, make sure your battery is at 100 percent again, then restart.

Battery Calibration Install on Google Play

9. Immediately launch the app and recalibrate your battery.

10. Once you've calibrated your battery, discharge it all the way down to 0 percent and let your phone turn off again.

11. Fully charge the battery one more time without interruption while it's switched off, and the Android system's battery percentage will be reset.

That's it. Have you tried any of these methods? Do you know an alternate way to fix battery problems? Let us know in the comments.



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  • I tried following the guide superficially, had to come back to follow it more closely and faithfully. In the end, this procedure worked for me (I used method 2) and my battery is working well again on my 2+ year old Nexus 6P. Thanks for the write-up!

  • All android smartphones have the same problem with baterry's life and there is no solution at all. Just buy an iphone... ;-)

    • My mom's iPhone had the same problem 3 months ago. The battery was dropping from 60% to 30% in minutes on idle and the phone was turning off at 20%. She took to the apple store and the Genius guy solution was: "buy a new iphone". It's current battery technology's problem and can happen with every gadget that uses it. The best way to postpone this in our battery powered gadgets is to avoid: plugging the charger every time, getting below 40% and charging over night.

    • I recently updated my Oneplus One to Lineage (android 7.1.2 I believe) and, right now, after 14 hours on battery and normal usage I still have 69% left.

      Seems alright to me, especially given it's 2.5 years old, used every day and running the original battery.

      Could have gone and dropped somewhere north of £600 for an iPhone I suppose (or a high-end Android for that matter) but for a couple of hours effort I've basically got a 'new' phone experience for free.

  • Most 'calibration' apps allow for enforcing a 100% mark at any given charge voltage. Which makes sense, if the phone does not reach 100% by itself, while the battery is hovering at a maximum voltage below the expected one (4.15V or so), e.g. when getting worn/older.
    But what to do if the percentage counter drops to 1% while the battery is still at a strong 3.74V level, far off the critical 3,5V vor Li batteries? How can I FORCE the system to stay up anyway?

    How can I adjust the VOLTAGE/PERCENTAGE relationship in Android? Apparently the system TRIES to be smart and shifts this relationship over time and after each charge cycle. But it makes HUGE errors and does not allow for a full usage of my 5000mAh battery this way.
    I know of a guy who owns the SAME device (Voyo Q101 4G) and saw his tablet's battery drop below 3V without shutting down. Mine does the opposite: it will not allow me to use it at ranges below 3.70V, no matter how much is left.

    Android revision changed so often over the years, yet they still have not learned to read battery voltage curves reliably???

  • When I try to drain the battery on my Motorola G it eventually gets to the point where, whenever I turn it on, it shuts off immediately afterwards. The problem with this is that it never truly gets to 0%; when I move onto the next step--plug you phone in until it is at 100%--it starts off at 40% not 0%. I was wondering if anyone else was having a similar problem with their device, and if they had found a solution or if the solution in the above article works even when the battery never gets to 0%. I'm also having issues with the flashlight widget and was wondering if they were related, because they both started to occur on the same day. Every time I click the widget the light flashes for half a second and then turns off, while the widget still indicates it is on.

  • You mean most of the time the phone will show 100% after starting.

  • I did the method 2 on a new genuine Samsung battery for my Note II. I have the battery for 2 months and for the past three days, in the morning the battery went from 30% to 0% the first day, from 50% to 0% the second day (on which I did a complete factory reset), and from 75% to 0% the third day. When trying to discharge the battery it took about 2 more hours after reaching 3%. It was working for 2 hours on 3%. I found that kind of weird but I guess that is why it needed to be calibrated. If this method works I will tell you tomorrow.

    The procedure worked! The battery does not drop to 0% anymore. I did however find that the Android OS was eating up 61% of my battery. It seems that the phone is working okay again. Will be checking the battery every morning. Thanks for the help!

  • 血と影 11 months ago Link to comment

    I tried doing this without root access method, but I don't know what to do since not matter how long I charge, it won't show the 100% charge sign and perpetually stays at 0%... I also tried leaving it charging completely turned off for 5 hours, and I turned it on but it still said 0% even after leaving it charged on for another 3 hours.

    • You tried a different charger?

      As the article points out, re-calibration isn't going to help if the issue is a dead battery. Many handsets have easily replaceable batteries. I've just replaced one in my wife's Nexus 4, took 10 minutes and cost under a fiver.

  • will calibration happens automatically if i factory reset the device or it stays with the same problem

  • My Nexus 5 did that once....i swear to god it charged it self a bit all by itself. My dad says some gadgets will do that when u leave them alone. Only happened once tho... seems like

  • So I have an extra battery and charger. I use my phone until it turns off, then swap batteries with the fully charged one. Am I doing more harm than good this way? I like it because I'm never tethered to a cord, and I never have a dead phone!

    • Hi Tracy, it's ok but if you want to be nice to your batteries it's better not discharge it completely. So I would recommend switching batteries when the battery level drops below 15 percent. Just don't discharge the batteries completely because that will descrease the overall battery life (I mean the overall life, not long it will keep your phone running with one charge).

  • When you say, 'let your phone discharge down to 0', does this mean using the phone to assist in the battery going down? Or do I just leave it until it goes down to 0 (if I leave it, that will be a long time, since the battery meter sometimes goes up even without charging)?

  • You state in your myth section that deleting batterystats.bin doesn't magically calibrate your battery. However, guess what the app in your method 2 does?

    • They said that they still believe that clearing the batterystats.bin doesn't help, but would include method 2 just to be fair. That's why they added method 2. Just in case someone was interested in clearing the batterystats.bin using the app.

  • Hey kayshot Kshatriya. Be appreciative that you got an answer at least instead of acting like a douchebag.

  • My tablet PC charges up 4.15V and shuts down at 3.6V. Is it possible to change the shutdown voltage ? I would like to reduce it to 3.5 or 3.4V.

  • Worst kind of author is one who sucks his own dick by rambling. Took you at least 1000 words to tell us how to calibrate a battery. Nobody cares about all the shit you added.

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