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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. Today we'll explain what battery calibration is, how to tell if you need to do it and how to do it, with or without root access.

ANDROIDPIT battery 1
This is how to calibrate your Android battery. / © ANDROIDPIT

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 of your phone, remove the cover and inspect the battery. Look for bulges or leaks. In the image below, the battery of our Galaxy S6 battery swelled up and pushed the non-removable back off the phone. If your phone also has a non-removable battery, keep an eye out for similar occurences. If your phone doesn't sit flat on the table anymore, that could also be a sign of a swollen battery.

Galaxy s6 back taking off 3
This is an obvious sign of a swollen battery. / © ANDROIDPIT

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.

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 6 wireless charging
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: 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.

Although some batteries do explode, it's 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.

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. 

I'd advise you to read these two background articles on battery technology from the Battery University too:

If your battery has given up the ghost 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 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 all the time. 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 automatically shut off when their safe limit is reached and there's always a little in reserve even if your phone won't start. But again: do this only 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 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 interests 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 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 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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  • 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 2 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.

  • 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!

  • 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.

  • I have applied method 1 to a Medion/Lenovo LIFETAB S10346 Tablet PC with a bad battery. The first discharge cycle (step 1) took about 80 minutes at the brightest display setting. The second discharge cycle (step 8) took about 60 minutes. So things actually got worse.

  • I have an LG G3 and i was browsing through my phone in the middle of the day, and my battery was around 55-60%, and the phone shut off and restarted and when it rebooted, the battery indicator displayed that i had 15% remaining on the battery.

    • My old moto defy and atrix 2 do the same but they don't reboot. Battery level can suddenly drop to 15% (low battery state). Guess I'll have to calibrate them soon. They've been this way for too long without being corrected.

  • Bram 8 months ago Link to comment

    My oneplus one doesnt charge properly. It only charges when i'm not using it or when it's powered off. Sometimes when i want to check it while charging it stops charging. The indicator however always shows the phone is charging, but the battery is draining. I completely don't know what i have to do, i already tried recalibrating the battery but nothing changed. Help please?

    • Sounds more like it's a problem with the charger - your phone isn't getting enough current from it to run the hardware and charge the battery at the same time. If you're using the supplied charger and cable, I'd contact OnePlus for support. If you're using a different charger or cable, well there's your problem.

  • My wife's Galaxy S4 is having power problems. We can put her battery in my son's S4 and it works relatively well so I don't believe it's the battery. In trying to do this calibration her phone will get to a state where it just continually reboots (I assume that the phone calculates that the battery is dead) and the only way for her to stop that is to remove the battery. How should we try to do this calibration?

    • I had a similar problem with my s2. kept vibrating and shutting off. no charging, no loading, i thought it was a dead battery or a dead phone. did a bit of research and found some info about the power button getting stuck. didnt look stuck or anything, but i took the phone appart, forced the internal power button out with a pin (be gentil) and cleaned out the plastic button on the outer case. solved that problem. now i'm just battling with battery discharging. looks like some app or firmware problems. different topic though. good luck :D

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