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8 min read 115 comments

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.

Battery calibration 101:

Battery calibration methods:

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.

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

  • Discharge your phone fully until it turns itself off.
  • Turn it on again and let it turn itself off.
  • Plug your phone into a charger and, without turning it on, let it charge until the on-screen or LED indicator says 100 percent.
  • Unplug your charger.
  • 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.
  • 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.
  • 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.
  • Now, let your battery discharge all the way down to 0 percent and let your phone turn off again.
  • 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 to make it more reliable. Readers have rightly pointed out in the comments that newer versions of this app ask for a disturbingly extensive list of device permissions. If this worries you, we recommend trying the above non-root method first, and only resort to a 3rd party app if the first method proves unhelpful.

Method 2

  • Discharge your phone fully until it turns itself off.
  • Turn it on and let it turn off again.
  • Plug your phone into a charger and, without turning it on, let it charge until the on-screen or LED indicator says 100 percent.
  • Unplug your charger.
  • 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.
  • 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.
  • 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.
  • Now, install the Battery Calibration app, and before you launch it, make sure your battery is at 100 percent again, then restart.
  • Immediately launch the app and recalibrate your battery.
  • Once you've calibrated your battery, discharge it all the way down to 0 percent and let your phone turn off again.
  • 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.

115 comments

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  • This app wants me sign up, get through my firewall, get a bunch of permissions AND SHARE RESOURCES. You are NUTS!!!


  • I don't follow this. The article talks of two different acts. Disconnecting the charger, and disconnecting the phone. For some time I wondered if the phone was looking for the inactive charger as a trigger. I think reading between the lines, it's just written a little awkwardly.

    I am a muppet. I need muppet proof instruction.


    • I'm back.. Sorry to of not added anything useful before. I was at a loss. Now I understand, it's interesting to see how literal I expected the instruction to be.

      For others phased out by this procedure, I will put it into a local direlect.

      You flatten it completely. Then try switching it on again, to flatten it a bit more. Just let it turn itself off. Next, without switching it on, you charge it right up. Then stop charging and switch the phone on. If it says it's full still, then flatten it again, then charge it again without switching the power. Done. Hopefully. You can walk away. However, if it didn't say full when you switched it on...

      Charge the phone to full. Then stop charging and reboot the phone. If it says less than full, Then start this chapter again. If your repeating this chapter, the battery will be a bit closer to full following each reboot. Once it manages to reboot and say it's full still (or you decide it's not going to) Than as per the first chapter. "Flatten it again, then charge it again without switching on. Done"


      Thank you for showing me this. I'm about 4th time round, and have gone from 59% to 64% using a phone left flat for months. As I charge past 69% I'm seeing 4.345V (using *#0228#) which is very close to the 4.38V I would personally bottle out at. Passing 75% it's still at 4.345V and did waver Higher to 4.352V passing 73%. Edit: Passing 85% now, the Voltage had table topped.

      I discharged mine recording video. I know batteries moan about camera's and filming keeps the screen on. I also put on the WiFi, Bluetooth and GPS, but the screen and camera were the most power hungry. I forgot the torch.


      • I failed. I went round and round, but it wouldn't budge far from the 65% I had before I started. So I let it discharge till it switched off, then charged it again, expecting it to see this as it's full 100% of capacity. No. It's 65% still. It's not believed this is my full capacity. I must of charged it from around 65% to full a dozen times. It still won't reboot with more than 70% showing. Then tells me I'm about an hour from full when I plug in.


    • Just UNINSTALL!


  • How do I kill the battery fast so I can start from scratch??


  • Sorry - I am new at this ..
    I was wondering what did you mean by "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."?
    I am going through it right now. Please help?
    Thank you!!


  • I'd first like to express my appreciation for this guide, thank you, but am I missing something here?

    It sure looks like the process given for Non-Rooted & Rooted phones (or Method 1 & 2) are exactly the same. The *only* difference is that those who use Method 2 have an additional two steps instructing them to install and run the "Battery Calibration" app.

    Furthermore, can someone please tell me why this app needs so many permissions (see bottom of comment)? The Privacy Policy the developer provides in the Google Play store link above is scant, a little over 1 page, and doesn't even begin to try to explain the necessity of the listed permissions.

    Here are both Methods side by side with Method 2 obviously shown in the parentheses:
    Method 1
    (Method 2)

    Discharge your phone fully until it turns itself off.
    (Discharge your phone fully until it turns itself off.)

    Turn it on again and let it turn itself off.
    (Turn it on and let it turn off again.)

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

    Unplug your charger.
    (Unplug your charger.)

    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.
    (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.)

    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.
    (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.)

    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.
    (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.)

    **
    EXTRA STEPS ???
    (Now, install the Battery Calibration app, and before you launch it, make sure your battery is at 100 percent again, then restart.)

    (Immediately launch the app and recalibrate your battery.)
    **

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

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

    ***
    [Battery Calibration App Permissions] Version 2.5.3 can access:
    In-app purchases
    Device & app history
    -retrieve running apps
    Location
    -approximate location (network-based)
    Phone
    -read phone status and identity
    Photos/Media/Files
    -read the contents of your USB storage
    -modify or delete the contents of your USB storage
    Storage
    -read the contents of your USB storage
    -modify or delete the contents of your USB storage
    Wi-Fi connection information
    -view Wi-Fi connections
    Device ID & call information
    -read phone status and identity
    Other
    -update component usage statistics
    -receive data from Internet
    -view network connections
    -change network connectivity
    -full network access
    -run at startup
    -control vibration
    -prevent device from sleeping
    -modify system settings


  • As said in the article, simply wiping the cache partition (using the old hardware power/volume shutdown and Android menu) may reset the battery gauge, regardless of a major OS upgrade. If that works, it's much quicker and easier, and can be done safely any time.

    I've gotten curious about the scientific proofs that charging to 80% and draining to 40% will nearly double the number of recharge cycles. If true, it really means that 100% cuts the number of potential cycles in half and that fully charging it up is actually damaging to the battery over time. Therefore, OEMs are murdering our devices by systematically overcharging them, both to make them work harder and have us replace them sooner. Apparently some apps help users achieve the optimum of scientific battery health and 80/40 rule long life. Just wondering what it does to effective Tesla mlleage claims as well as battery hours claims of smartphones - if the trade off for a full charge is a $5000 car battery or $1000 phone that needs replacing twice as soon.


    • 1st off, your "under 40% or over 80%" rule only holds true roughly for lithium ion, not lithium polymer batteries (so laptops, power tools, 18650 battery cells, but not flat batteries like in your phone.) Other battery types have different limits to what is damaging or not. The cell phone manufacturers are aware of the limits of the lithium polymer batteries they use, and rarely make mistakes (Like the Samsung Note) in what is considered 0% (let's just say where the battery is actually at 30% voltage,) and 100% (let's just say 90% for the sake of giving it a number.) So when you see 100%, it doesn't mean it's overcharged at all, or damaging the battery. I'm not even sure how much can be calibrated versus being set by the manufacturer in the firmware. Even if you install aftermarket firmware on a rooted device with an unlocked bootloader, it still will have a unique way of calibrating the battery as far as I know, for that specific device, hence one of the reasons there is different firmware written for each model, even if almost identical. (Like the s8 vs. s8+ u models.)


  • Google now detect rooted device and rooted device bad for banking app and make our data vulnerable, i used too rooting before but now i'm get over it. All smartphone maker All brand will never give their customer smartphone full management access. So get used to 60-70% performance, far from max technology can do.

    And all brand now just thinking to make money from their Chip, Memory and Camera. So don't be surprise if development on Screen Technology, Battery Technology and model "IS" in turtle mode.

    I miss Steve Job (R.I.P), He definitely make a breakthrough with this slow phase development. Hope someone will push the boundary and make a significant breakthrough so we can have more advance development in smartphone.

    For now just enjoy what we have.......Peace.


    • Having a rooted device doesn't make your data vulnerable, but you can install software on it when it's rooted that can. Yes they do let users set the performance as high as possible on most phones I'm aware of, to the extent it doesn't damage the phone. That's why the high end phones come with different "power options" like "max performance" or "power saving". For rooted devices you can even overclock your processor or RAM. I'm not sure what paranoid delusions you're writing that comment based upon, but I assure you that you're wrong. Why would Samsung lock you out of a higher performance mode, so you'll enjoy the LG model instead of their product? Or did you forget there are many companies that make phones and they compete.... not by downgrading their product I'm sure.

      By the way, Steve Job died earlier than he should've because he didn't believe in science, and thought a "homeopathic remedy for cancer" would work. I'll agree he had some good inventions, but nothing that another company didn't make better for cheaper. The worst part of Steve Jobs is the "organic food" eating computer/science illiterate crowd that buys their products to compensate for their computer illiteracy, thinking more $ means easier to use, or somehow less vulnerable to "viruses".


      • @WEO KX

        I love your comment!!! I enjoy Android phones for the ability to roll up your sleeves (Rooting) and repair any inherent flaws one may find in performance or asthetics, thustly extending it's shelf life far beyond the planned obsolescence (By locking out Root privileges) by the manufacturer dictates (Two years?).

        i.e. My Galaxy Tab 3 running Nougat 7.1.2 and running it flawlessly. Not a fan of Oreo or the upcoming P.

        Security wise, if you visit stupid websites, download apps from stupid places, open stupid emails, and connect to insecure Wifi because you think it's cute, ect...you deserve to be innudated with every virus known to man. Root is not a factor in stupid decisions.

        Funnier still are those who have not the minimum of interest in knowing exactly how the device that holds their personal data actually operates...as long as the phone 'Just Works'.

        Cheers!


  • 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.


    • i don't think so....my android phone is around 4 yrs with me now and still has good battery....sometimes it depends on the owner/user


    • ----->


    • Not sure how spending more money for the same thing makes you feel better about your phone or yourself. But if you can't spell battery, I suppose there's not much to argue with. I'll gladly spend 3/4 the price for the same hardware or better. With substantially better software. If my s8+ can last 1 week on power saving mode, and 2 days on maximum power, and it's big enough I can hit the on-screen keyboard buttons without being a 3 foot tall midget with microscopic hands, then I'll stick with what I have.

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