How accurate is calculated/measured mAh
The app calibration screen provides a battery real capacity (mAh) based on historical charge cycle data being logged by the app.
First, it's important to differentiate the 2 types of phones:
- Phones providing real mA measures
- Phones not providing mA measures while charging (main screen shows "Estimated: xx mA" while charging)
The first category of phones, with real mA measures, will calculate real battery capacity mAh no matter how the app is configured.
The second category requires special attention and the app need to be configured in this way:
- A battery profile must be created with the manufacturer's specified battery capacity (mAh) and the AC charger output power or
- The in-use capacity must be set to the manufacturer's specs
- The AC charger output power must be set matching charger's specs.
The app will then use 3 simple facts to determine the real battery capacity:
- Charging can't go over the charger output power (frequently 1000mA).
- From 0% to 50%, phone uses the maximum charger capacity.
- Above 50% charging rate is lowered to protect battery from aging faster.
If the charging consistently goes over the charger power, it means the defined mAh is over-estimated and the app will adjust the results accordingly.
If the charging consistenly stays lower than charger power while screen is off, it means the defined mAh is under-estimated and the app will adjust the results accordingly.
So it's important to set the original battery capacity when using extended battery as it is easier to adjust over-estimated values than adjust under-estimated because the later requires the screen to be switched off. While screen is on charging is always lower than charger power hence the need to have the screen off.
Whether the battery capacity is set to 2000mAh or 20.000mAh the app will easily discover a lower battery capacity because the charging (mA) will consistently be above actual charging power between 0% and 50%.
Here is a way to correlate the results: Charging times increase with battery capacity, eg a 3500mAh battery must take longer to charge than a 2100mAh battery.