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Samsung Phone Battery Calibration Guide

Description:

  • This guide is for those who are experiencing battery issues (e.g., battery suddenly dying at percentages >1% or battery draining too fast or messed up battery readings after custom ROM flash). If your phone is relatively new, unless if it came with a factory defect or you somehow managed to physically damage it, the battery shouldn’t need to be calibrated like this.

  • Lithium-Ion batteries really do degrade over time (e.g., voltage sag, electron migration, possibility of dendrites even) at around 500 or so full charge-discharge cycles and as such, old batteries will NEVER perform as well as new ones despite how much calibration you try to perform. You CAN NOT improve battery life with calibration and what this serves to do is just to make the phone read more accurate battery percentages to prevent aforementioned battery related issues from occurring, especially when one flashes custom ROMS quite regularly.

  • Also, despite what many apps claim to do, this guide is actually more effective than those, at least based on personal experience, in actually performing battery calibration on Samsung devices since even apps that require root permissions only delete the batterystats.bin file after telling the user to charge to 100% after a drain to 0% and as explained below, this solely can not fix your problems nor really do anything to calibrate your battery on your phone so results from these types of apps are really a hit-or-miss affair to say the very least.

Requirements:
  • Samsung/TouchWiz/OneUI Based Firmware/ROM
  • Phone Dialer App
  • A Samsung Phone with a poorly performing inaccurate battery that isn't really required to be replaced yet
  • USSD Code *#0228# (For Battery Menu & Fuel Gauge Reset)
  • USSD Code *#9900# (For System Dump Menu & Battery Stats Bin Reset)

*Quick Reset is a built-in function exclusive to Samsung phones used by their tech & support to really calibrate phones that are reading very inaccurate battery percentages by resetting the battery fuel gauge (no app or script can do what this does as far as I know, at least for Samsung phones and it has been proven to be very effective at making the phone more accurately read how much the phone is using relative to maximum battery capacity and usage)

*Resetting batterystats.bin, while it does not really calibrate nor improve your battery like what a lot of people espouse, what it does do is reset the battery information file so that the phone would be "fresh" and the battery usage learning A.I. such as adaptive battery won't accidentally base its optimizations on your old "inaccurate" usage and battery performance



Method 1 (Best Method)

1. Drain Battery to 5%
2. Open phone dialer and type *#0228# then click “Quick Start” then press “OK” when the warning prompt comes up (note that this won’t work if you are plugged in still so unplug first before attempting to run this USSD code)
3. Wait for phone screen to turn on again and notice your battery percentage (it should have gone down to your actual battery percentage)
4. Charge the device to 100% without interruptions
5. Turn off the phone then turn it on again then unplug it from the Charger
6. Repeat Steps 2-4 for around 3 more times (after approximately the third time, battery readings should be leveled out and it should read 100% even after pressing quick start; if not, repeat a few more times and if it still won’t level out then that means your battery is yearning for a replacement)
7. With the phone plugged in at 100%, go back to phone dialer and type *#9900# then scroll down to “batterystats.bin reset” and click it
8. Exit the SysDump Menu and reboot the phone
9. Repeat Steps 1-8 after a week
10. Enjoy More Accurate Battery Readings!


Method 2 (Quicker Alternative to Method 1)

1. Open phone dialer and type *#0228# then click “Quick Start” then press “OK” when the warning prompt comes up (note that this won’t work if you are plugged in still so unplug first before attempting to run this USSD code)
2. Wait for phone screen to turn on again and notice your battery percentage (it should have gone down to your actual battery percentage)
3. Charge the device to 100% without interruptions
4. Repeat Steps 1-3 for around 3 more times (after approximately the third time, battery readings should be leveled out and it should read 100% even after pressing quick start; if not, repeat a few more times and if it still won’t level out then that means your battery is yearning for a replacement)
5. Repeat Steps 1-4 after a week
6. Enjoy More Accurate Battery Readings!


Method 3 (For Phones That Don’t Have the USSD Codes Mentioned Like Non-Samsung Phones)

1. Drain battery to 0%
2. Turn off the phone
3. Charge to 100% without interruptions
4. Turn on phone then if battery isn’t at 100%, charge until 100%
5. Unplug then reboot
6. If again the battery isn’t at 100%, charge until 100% then repeat as many times as necessary until 100% is 100% even after a reboot
7. Enjoy More Accurate Battery Readings!


Method 4 (Not Recommended and ONLY for EXTREMELY BAD cases of Battery Calibration)

1. Drain battery to 0%
2. Turn the phone back on
3. If it dies again, keep turning it on repeatedly until the boot logo/animation doesn’t show up anymore
4. Charge until 100% while the phone is off without interruptions
5. Turn on the phone
6. Enjoy More Accurate Battery Readings!


*Note that Methods 1 & 2, at least based on personal experience with Samsung phones, are the most effective ones while Method 3 is a more generic methodology that may work for non-Samsung phones as well. On the other hand, method 4 MAY POTENTIALLY hasten battery degradation if done too often so it isn’t really advised to do so unless if the phone has no USSD codes aforementioned even on its stock firmware and battery readings are already a mess.

*You can try to flash your latest stock firmware if the USSD codes aren’t supported by your current custom ROM (e.g., CM, LineageOS, Note7 Port, etc.) then perform Methods 1 or 2 then use the phone for a few charge-discharge cycles then go back and flash your preferred custom Recovery, ROM, Kernel, Vendor, API, Mods, Root, etc.…

*If any of the above methods do not seem to work, then your battery is basically waving goodbye at you…
 
Last edited:
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Here are some notable Q&A's regarding the process:

Q: Is my 2+ year old battery going to improve after this process?
A: It's hard to say as it is dependent upon many different factors such as how you use your phone, how many times you run it down to 0%, how often you charge, etc.... In short, it may or may not work in your favor as by this point, you are usually up to your 1000th+ charge cycle and the degradation can be so much so as to warrant a battery replacement instead of any software-related methodologies such as the guide above.

Q: Is there a way to link certain mV readings of the battery to its charge percentage?
A: I'm afraid this is very difficult if impossible and impractical since battery voltage readings regularly fluctuate by significant amounts during use and when not in use, depending on the workload and current draw. As such, voltage readings shouldn't be your main basis, if at all, when calibrating your battery. Sure, the voltage readings do go down when your charge goes down, but from 100%-90% the voltage for Lithium Ion batteries could be 4.2v-4v, and for around 80%-40% it could be around 3.9v-3.7v so the voltage vis a vis charge percentage is non-linear and variable, therefore not feasibly linkable to charge percentage.

Q: Do you really need to wipe the battery stats bin file as the old saying goes?
A: No not really since it has already been debunked that wiping this particular file only wipes the battery usage information such as the one visible from device care or in the settings, not the max or min limits of the battery percentage or anything else of further use. I only specifically included it in this guide so that you could start monitoring your battery performance from scratch and not get confused with your old usage and battery performance, since adaptive technology that uses A.I. such as adaptive battery in newer Android versions base their decisions on your past usage and having your old usage there to base on wouldn't be recommended if you want a fresh start.

Q: Is bump charging (charging to 100% unplugging then charging back to 100% repeatedly) recommended?
A: It isn't incredibly bad to do once and a while, although personally I wouldn't recommended doing so often. This is because with bump charging, you are basically trying to bypass the maximum limitations set by the OEM's as to how much you can charge past "100%" since "100%" on the phone isn't really that, instead it is sometimes around 85%-95% in reality so that you are physically limited from normally charging your Li-Ion battery to true full since this is very bad for its performance, longevity, and goes against its recommended usage. The same principle applies to the phone's "0%" in which it isn't actually true 0% as allowing the user to reach this would mean battery death in which it's own circuitry would shut it off to the point that you cannot recharge it without special equipment.


Q: Why do I see many different ways to calibrate and use the battery fuel gauge reset technique?
A: This is because Samsung hasn't given any official statements nor guides regarding this tool since they only use it internally and why would they teach the public how to use it if the users can just send in their phones to their service centers and they can charge them as they see fit? Well, conspiracy aside, some batteries and phones react differently to certain methodologies in which some phones, after tapping the reset fuel gauge, would actually jump up in percentage instead of normally dropping down. Some can get stuck at a certain percentage and some won't. Additionally, different people interpret the way the fuel gauge reset works differently so different guides can tell you different ways to do it, correct or not. As an example, this guide may not be correct at all yet as long as it works to some extent based on personal experience, then I don't see the harm in trying.

Q: Why is my phone draining faster after doing this fuel gauge reset?
A: It may be because the intent for resetting the gauge is so that it could try to figure out on its own more accurate readings and initially, at least for the first three charge-discharge cycles or so, it is still finding out if the battery should be at this percentage or that percentage. It is sort of like training itself but it should settle down after a few full charges and discharges.

Q: Can I trust battery health apps even if they request root access?
A: This can make them seem legit, but most of the time their effects are negligible at best. Take what they advertise with a grain of salt always. This is since no app can ever truly determine actual battery health and you usually need hardware tools for that since even Android can only say "Good" under battery health and no further details whatsoever.

Q: When I buy a new battery, is it actually new and better?
A: This depends on whether the battery you got was manufactured recently or back when your phone was still in the market. Remember that batteries degrade even when not in use and when stored, so always check the manufacture date of your battery and also check if it isn't some cheap Chinese knock-off imitation (fire-hazard beware!). If you aren't sure, just let Samsung deal with the battery replacement, albeit more costly.

Q: For the J7 Prime specifically, how good can I expect the battery to be?
A: As a long-time owner of this device as long as it first came out in early 2017, I could say that when you have installed recent Android versions through custom ROMS, like Android 9 Pie to Android 10 Q, the battery drain can be much more significant than it was back when it was specially on Android 6 MM since there are a lot more processes, app updates designed for more powerful phones, A.I. technology in the background, and new ways by which the OS works in general so it is tailored for newer and better devices and making it work on this relatively old phone is like running Windows 10 with all its features on a kid's computer from the 90's. Generally, with mixed usage, the phone can last you through the day with a single charge in the morning, with around 3-4 hours of screen on time. When gaming or streaming, SOT can be around 2-3 hours. Standby drain is noticeably worse on newer versions of Android as well. Back on marshmallow, the device can last around 2 days on mixed usage with 4-6 hours screen on time and very insignificant standby drain. Also, note that the device was newer back then so there's that.

Q: Can certain ROMS affect battery performance?
A: Absolutely! I've used unofficial CyanogenMod ROMS back then on my older phones and the battery drain was horrendous with around 2 hours battery life on standby and around 30 minutes or so of SOT! It all depends on how well optimized the ROMS are for the device so always check the feedback and developer's notes before installing any new custom ROM around here.

Q: Why is my phone battery percentage different in TWRP or OrangeFox Recovery than it is inside the OS?

A: This can happen on some devices such as the J7 Prime and other devices from other manufacturers even. I do not know for sure why, but it could be (1), either the recovery or the OS is delayed in reading the correct battery percentage and are out of sync, (2) a bug with the recovery or is device-specific, or (3) the battery needs calibration, although this last one isn't usually the case for phones such as the J7P where this "difference" could appear from time to time even when the battery is already well calibrated.
 
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Fablo

Member
Oct 6, 2020
8
1
24
Thank you for that guide! I used it to calibrate my A70 Battery (4000 mAh) which i use in my A7 2018 (original 3000 mAh). I did the second method and had to do the 3 steps about 7 times. I had to restart my phone after every try to get my real percentage, it usually jumped from 100% fully charged to 65%.
 
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kingrohan

Member
Apr 29, 2013
6
3
Allahabad
Samsung Phone Battery Calibration Guide

Description:

  • This guide is for those who are experiencing battery issues (e.g., battery suddenly dying at percentages >1% or battery draining too fast or messed up battery readings after custom ROM flash). If your phone is relatively new, unless if it came with a factory defect or you somehow managed to physically damage it, the battery shouldn’t need to be calibrated like this.

  • Lithium-Ion batteries really do degrade over time (e.g., voltage sag, electron migration, possibility of dendrites even) at around 500 or so full charge-discharge cycles and as such, old batteries will NEVER perform as well as new ones despite how much calibration you try to perform. You CAN NOT improve battery life with calibration and what this serves to do is just to make the phone read more accurate battery percentages to prevent aforementioned battery related issues from occurring, especially when one flashes custom ROMS quite regularly.

  • Also, despite what many apps claim to do, this guide is actually more effective than those, at least based on personal experience, in actually performing battery calibration on Samsung devices since even apps that require root permissions only delete the batterystats.bin file after telling the user to charge to 100% after a drain to 0% and as explained below, this solely can not fix your problems nor really do anything to calibrate your battery on your phone so results from these types of apps are really a hit-or-miss affair to say the very least.

Requirements:
  • Samsung/TouchWiz/OneUI Based Firmware/ROM
  • Phone Dialer App
  • A Samsung Phone with a poorly performing inaccurate battery that isn't really required to be replaced yet
  • USSD Code *#0228# (For Battery Menu & Fuel Gauge Reset)
  • USSD Code *#9900# (For System Dump Menu & Battery Stats Bin Reset)

*Quick Reset is a built-in function exclusive to Samsung phones used by their tech & support to really calibrate phones that are reading very inaccurate battery percentages by resetting the battery fuel gauge (no app or script can do what this does as far as I know, at least for Samsung phones and it has been proven to be very effective at making the phone more accurately read how much the phone is using relative to maximum battery capacity and usage)

*Resetting batterystats.bin, while it does not really calibrate nor improve your battery like what a lot of people espouse, what it does do is reset the battery information file so that the phone would be "fresh" and the battery usage learning A.I. such as adaptive battery won't accidentally base its optimizations on your old "inaccurate" usage and battery performance



Method 1 (Best Method)

1. Drain Battery to 5%
2. Open phone dialer and type *#0228# then click “Quick Start” then press “OK” when the warning prompt comes up (note that this won’t work if you are plugged in still so unplug first before attempting to run this USSD code)
3. Wait for phone screen to turn on again and notice your battery percentage (it should have gone down to your actual battery percentage)
4. Charge the device to 100% without interruptions
5. Turn off the phone then turn it on again then unplug it from the Charger
6. Repeat Steps 2-4 for around 3 more times (after approximately the third time, battery readings should be leveled out and it should read 100% even after pressing quick start; if not, repeat a few more times and if it still won’t level out then that means your battery is yearning for a replacement)
7. With the phone plugged in at 100%, go back to phone dialer and type *#9900# then scroll down to “batterystats.bin reset” and click it
8. Exit the SysDump Menu and reboot the phone
9. Repeat Steps 1-8 after a week
10. Enjoy More Accurate Battery Readings!


Method 2 (Quicker Alternative to Method 1)

1. Open phone dialer and type *#0228# then click “Quick Start” then press “OK” when the warning prompt comes up (note that this won’t work if you are plugged in still so unplug first before attempting to run this USSD code)
2. Wait for phone screen to turn on again and notice your battery percentage (it should have gone down to your actual battery percentage)
3. Charge the device to 100% without interruptions
4. Repeat Steps 1-3 for around 3 more times (after approximately the third time, battery readings should be leveled out and it should read 100% even after pressing quick start; if not, repeat a few more times and if it still won’t level out then that means your battery is yearning for a replacement)
5. Repeat Steps 1-4 after a week
6. Enjoy More Accurate Battery Readings!


Method 3 (For Phones That Don’t Have the USSD Codes Mentioned Like Non-Samsung Phones)

1. Drain battery to 0%
2. Turn off the phone
3. Charge to 100% without interruptions
4. Turn on phone then if battery isn’t at 100%, charge until 100%
5. Unplug then reboot
6. If again the battery isn’t at 100%, charge until 100% then repeat as many times as necessary until 100% is 100% even after a reboot
7. Enjoy More Accurate Battery Readings!


Method 4 (Not Recommended and ONLY for EXTREMELY BAD cases of Battery Calibration)

1. Drain battery to 0%
2. Turn the phone back on
3. If it dies again, keep turning it on repeatedly until the boot logo/animation doesn’t show up anymore
4. Charge until 100% while the phone is off without interruptions
5. Turn on the phone
6. Enjoy More Accurate Battery Readings!


*Note that Methods 1 & 2, at least based on personal experience with Samsung phones, are the most effective ones while Method 3 is a more generic methodology that may work for non-Samsung phones as well. On the other hand, method 4 MAY POTENTIALLY hasten battery degradation if done too often so it isn’t really advised to do so unless if the phone has no USSD codes aforementioned even on its stock firmware and battery readings are already a mess.

*You can try to flash your latest stock firmware if the USSD codes aren’t supported by your current custom ROM (e.g., CM, LineageOS, Note7 Port, etc.) then perform Methods 1 or 2 then use the phone for a few charge-discharge cycles then go back and flash your preferred custom Recovery, ROM, Kernel, Vendor, API, Mods, Root, etc.…

*If any of the above methods do not seem to work, then your battery is basically waving goodbye at you…
Hello, I followed the first method for my tab S4, it was shutting down instantly as soon as it reached 15- 20 %. but it happened sometimes, not everyday.
So I did as you told in the first method, but I think I probably messed up somewhere, Now what is happening is, as soon as it reaches above 60% during charging, it slows down to like how it slowly charges when above 90%.
Battery backup is as same as before, so that it means its reading 65% as 100%.
How can I rectify it, battery is getting fully charged as 65 - 70%.
How can I reset the gauge again so that it shows correct percentage.
 
Hello, I followed the first method for my tab S4, it was shutting down instantly as soon as it reached 15- 20 %. but it happened sometimes, not everyday.
So I did as you told in the first method, but I think I probably messed up somewhere, Now what is happening is, as soon as it reaches above 60% during charging, it slows down to like how it slowly charges when above 90%.
Battery backup is as same as before, so that it means its reading 65% as 100%.
How can I rectify it, battery is getting fully charged as 65 - 70%.
How can I reset the gauge again so that it shows correct percentage.

Try repeating the procedure again. It might work it might not. Sometimes phones might read way off so try again. Drain it then repeat steps
 

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  • 2
    Samsung Phone Battery Calibration Guide

    Description:

    • This guide is for those who are experiencing battery issues (e.g., battery suddenly dying at percentages >1% or battery draining too fast or messed up battery readings after custom ROM flash). If your phone is relatively new, unless if it came with a factory defect or you somehow managed to physically damage it, the battery shouldn’t need to be calibrated like this.

    • Lithium-Ion batteries really do degrade over time (e.g., voltage sag, electron migration, possibility of dendrites even) at around 500 or so full charge-discharge cycles and as such, old batteries will NEVER perform as well as new ones despite how much calibration you try to perform. You CAN NOT improve battery life with calibration and what this serves to do is just to make the phone read more accurate battery percentages to prevent aforementioned battery related issues from occurring, especially when one flashes custom ROMS quite regularly.

    • Also, despite what many apps claim to do, this guide is actually more effective than those, at least based on personal experience, in actually performing battery calibration on Samsung devices since even apps that require root permissions only delete the batterystats.bin file after telling the user to charge to 100% after a drain to 0% and as explained below, this solely can not fix your problems nor really do anything to calibrate your battery on your phone so results from these types of apps are really a hit-or-miss affair to say the very least.

    Requirements:
    • Samsung/TouchWiz/OneUI Based Firmware/ROM
    • Phone Dialer App
    • A Samsung Phone with a poorly performing inaccurate battery that isn't really required to be replaced yet
    • USSD Code *#0228# (For Battery Menu & Fuel Gauge Reset)
    • USSD Code *#9900# (For System Dump Menu & Battery Stats Bin Reset)

    *Quick Reset is a built-in function exclusive to Samsung phones used by their tech & support to really calibrate phones that are reading very inaccurate battery percentages by resetting the battery fuel gauge (no app or script can do what this does as far as I know, at least for Samsung phones and it has been proven to be very effective at making the phone more accurately read how much the phone is using relative to maximum battery capacity and usage)

    *Resetting batterystats.bin, while it does not really calibrate nor improve your battery like what a lot of people espouse, what it does do is reset the battery information file so that the phone would be "fresh" and the battery usage learning A.I. such as adaptive battery won't accidentally base its optimizations on your old "inaccurate" usage and battery performance



    Method 1 (Best Method)

    1. Drain Battery to 5%
    2. Open phone dialer and type *#0228# then click “Quick Start” then press “OK” when the warning prompt comes up (note that this won’t work if you are plugged in still so unplug first before attempting to run this USSD code)
    3. Wait for phone screen to turn on again and notice your battery percentage (it should have gone down to your actual battery percentage)
    4. Charge the device to 100% without interruptions
    5. Turn off the phone then turn it on again then unplug it from the Charger
    6. Repeat Steps 2-4 for around 3 more times (after approximately the third time, battery readings should be leveled out and it should read 100% even after pressing quick start; if not, repeat a few more times and if it still won’t level out then that means your battery is yearning for a replacement)
    7. With the phone plugged in at 100%, go back to phone dialer and type *#9900# then scroll down to “batterystats.bin reset” and click it
    8. Exit the SysDump Menu and reboot the phone
    9. Repeat Steps 1-8 after a week
    10. Enjoy More Accurate Battery Readings!


    Method 2 (Quicker Alternative to Method 1)

    1. Open phone dialer and type *#0228# then click “Quick Start” then press “OK” when the warning prompt comes up (note that this won’t work if you are plugged in still so unplug first before attempting to run this USSD code)
    2. Wait for phone screen to turn on again and notice your battery percentage (it should have gone down to your actual battery percentage)
    3. Charge the device to 100% without interruptions
    4. Repeat Steps 1-3 for around 3 more times (after approximately the third time, battery readings should be leveled out and it should read 100% even after pressing quick start; if not, repeat a few more times and if it still won’t level out then that means your battery is yearning for a replacement)
    5. Repeat Steps 1-4 after a week
    6. Enjoy More Accurate Battery Readings!


    Method 3 (For Phones That Don’t Have the USSD Codes Mentioned Like Non-Samsung Phones)

    1. Drain battery to 0%
    2. Turn off the phone
    3. Charge to 100% without interruptions
    4. Turn on phone then if battery isn’t at 100%, charge until 100%
    5. Unplug then reboot
    6. If again the battery isn’t at 100%, charge until 100% then repeat as many times as necessary until 100% is 100% even after a reboot
    7. Enjoy More Accurate Battery Readings!


    Method 4 (Not Recommended and ONLY for EXTREMELY BAD cases of Battery Calibration)

    1. Drain battery to 0%
    2. Turn the phone back on
    3. If it dies again, keep turning it on repeatedly until the boot logo/animation doesn’t show up anymore
    4. Charge until 100% while the phone is off without interruptions
    5. Turn on the phone
    6. Enjoy More Accurate Battery Readings!


    *Note that Methods 1 & 2, at least based on personal experience with Samsung phones, are the most effective ones while Method 3 is a more generic methodology that may work for non-Samsung phones as well. On the other hand, method 4 MAY POTENTIALLY hasten battery degradation if done too often so it isn’t really advised to do so unless if the phone has no USSD codes aforementioned even on its stock firmware and battery readings are already a mess.

    *You can try to flash your latest stock firmware if the USSD codes aren’t supported by your current custom ROM (e.g., CM, LineageOS, Note7 Port, etc.) then perform Methods 1 or 2 then use the phone for a few charge-discharge cycles then go back and flash your preferred custom Recovery, ROM, Kernel, Vendor, API, Mods, Root, etc.…

    *If any of the above methods do not seem to work, then your battery is basically waving goodbye at you…
    2
    Here are some notable Q&A's regarding the process:

    Q: Is my 2+ year old battery going to improve after this process?
    A: It's hard to say as it is dependent upon many different factors such as how you use your phone, how many times you run it down to 0%, how often you charge, etc.... In short, it may or may not work in your favor as by this point, you are usually up to your 1000th+ charge cycle and the degradation can be so much so as to warrant a battery replacement instead of any software-related methodologies such as the guide above.

    Q: Is there a way to link certain mV readings of the battery to its charge percentage?
    A: I'm afraid this is very difficult if impossible and impractical since battery voltage readings regularly fluctuate by significant amounts during use and when not in use, depending on the workload and current draw. As such, voltage readings shouldn't be your main basis, if at all, when calibrating your battery. Sure, the voltage readings do go down when your charge goes down, but from 100%-90% the voltage for Lithium Ion batteries could be 4.2v-4v, and for around 80%-40% it could be around 3.9v-3.7v so the voltage vis a vis charge percentage is non-linear and variable, therefore not feasibly linkable to charge percentage.

    Q: Do you really need to wipe the battery stats bin file as the old saying goes?
    A: No not really since it has already been debunked that wiping this particular file only wipes the battery usage information such as the one visible from device care or in the settings, not the max or min limits of the battery percentage or anything else of further use. I only specifically included it in this guide so that you could start monitoring your battery performance from scratch and not get confused with your old usage and battery performance, since adaptive technology that uses A.I. such as adaptive battery in newer Android versions base their decisions on your past usage and having your old usage there to base on wouldn't be recommended if you want a fresh start.

    Q: Is bump charging (charging to 100% unplugging then charging back to 100% repeatedly) recommended?
    A: It isn't incredibly bad to do once and a while, although personally I wouldn't recommended doing so often. This is because with bump charging, you are basically trying to bypass the maximum limitations set by the OEM's as to how much you can charge past "100%" since "100%" on the phone isn't really that, instead it is sometimes around 85%-95% in reality so that you are physically limited from normally charging your Li-Ion battery to true full since this is very bad for its performance, longevity, and goes against its recommended usage. The same principle applies to the phone's "0%" in which it isn't actually true 0% as allowing the user to reach this would mean battery death in which it's own circuitry would shut it off to the point that you cannot recharge it without special equipment.


    Q: Why do I see many different ways to calibrate and use the battery fuel gauge reset technique?
    A: This is because Samsung hasn't given any official statements nor guides regarding this tool since they only use it internally and why would they teach the public how to use it if the users can just send in their phones to their service centers and they can charge them as they see fit? Well, conspiracy aside, some batteries and phones react differently to certain methodologies in which some phones, after tapping the reset fuel gauge, would actually jump up in percentage instead of normally dropping down. Some can get stuck at a certain percentage and some won't. Additionally, different people interpret the way the fuel gauge reset works differently so different guides can tell you different ways to do it, correct or not. As an example, this guide may not be correct at all yet as long as it works to some extent based on personal experience, then I don't see the harm in trying.

    Q: Why is my phone draining faster after doing this fuel gauge reset?
    A: It may be because the intent for resetting the gauge is so that it could try to figure out on its own more accurate readings and initially, at least for the first three charge-discharge cycles or so, it is still finding out if the battery should be at this percentage or that percentage. It is sort of like training itself but it should settle down after a few full charges and discharges.

    Q: Can I trust battery health apps even if they request root access?
    A: This can make them seem legit, but most of the time their effects are negligible at best. Take what they advertise with a grain of salt always. This is since no app can ever truly determine actual battery health and you usually need hardware tools for that since even Android can only say "Good" under battery health and no further details whatsoever.

    Q: When I buy a new battery, is it actually new and better?
    A: This depends on whether the battery you got was manufactured recently or back when your phone was still in the market. Remember that batteries degrade even when not in use and when stored, so always check the manufacture date of your battery and also check if it isn't some cheap Chinese knock-off imitation (fire-hazard beware!). If you aren't sure, just let Samsung deal with the battery replacement, albeit more costly.

    Q: For the J7 Prime specifically, how good can I expect the battery to be?
    A: As a long-time owner of this device as long as it first came out in early 2017, I could say that when you have installed recent Android versions through custom ROMS, like Android 9 Pie to Android 10 Q, the battery drain can be much more significant than it was back when it was specially on Android 6 MM since there are a lot more processes, app updates designed for more powerful phones, A.I. technology in the background, and new ways by which the OS works in general so it is tailored for newer and better devices and making it work on this relatively old phone is like running Windows 10 with all its features on a kid's computer from the 90's. Generally, with mixed usage, the phone can last you through the day with a single charge in the morning, with around 3-4 hours of screen on time. When gaming or streaming, SOT can be around 2-3 hours. Standby drain is noticeably worse on newer versions of Android as well. Back on marshmallow, the device can last around 2 days on mixed usage with 4-6 hours screen on time and very insignificant standby drain. Also, note that the device was newer back then so there's that.

    Q: Can certain ROMS affect battery performance?
    A: Absolutely! I've used unofficial CyanogenMod ROMS back then on my older phones and the battery drain was horrendous with around 2 hours battery life on standby and around 30 minutes or so of SOT! It all depends on how well optimized the ROMS are for the device so always check the feedback and developer's notes before installing any new custom ROM around here.

    Q: Why is my phone battery percentage different in TWRP or OrangeFox Recovery than it is inside the OS?

    A: This can happen on some devices such as the J7 Prime and other devices from other manufacturers even. I do not know for sure why, but it could be (1), either the recovery or the OS is delayed in reading the correct battery percentage and are out of sync, (2) a bug with the recovery or is device-specific, or (3) the battery needs calibration, although this last one isn't usually the case for phones such as the J7P where this "difference" could appear from time to time even when the battery is already well calibrated.
    1
    Thank you for that guide! I used it to calibrate my A70 Battery (4000 mAh) which i use in my A7 2018 (original 3000 mAh). I did the second method and had to do the 3 steps about 7 times. I had to restart my phone after every try to get my real percentage, it usually jumped from 100% fully charged to 65%.