How to check the Battery Health of your Samsung phone

If you want to figure out the battery health and number of charge cycles your device has so far (good to determine if a battery replacement is needed or when buying a preowned/refurbished one), you can do the following:

• Open the Dialer, enter *#9900#.
• Scroll to the bottom, and select Run dumpstate & copy to sdcard. This can take a few minutes, but the ZIP archive's default filename and the location it'll be saved in will pop up when it's done.
• Exit on the bottom or press the home button/back button.
• Connect the phone to the computer (or send the file to one), browse internal storage and go under the log folder, and copy the ZIP file to a computer. Open the archive and look for the dumpstate.txt file.
• Search for mSavedBatteryAsoc which is the battery health percentage (the closer it is to 100% the better) and mSavedBatteryUsage dividing the number by 100 gives you the charge cycles.

To delete the log on the phone, open the Dialer again, put in *#9900# and choose Delete dumpstate/logcat.