[Samsung Galaxy J7 Prime / J7 On NXT (Exynos7870)] Mightx:
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…