Ampere Pro works on Android 4.0.3+ devices. Not every device is supported because there are devices which lacks an appropriate measurement chip (or the interface) and they can not be supported at all. Please read the list of not supported phones at the end of the description. Ampere is not meant to be mA accurate.
Ampere Pro is only good for evaluate which Charger/USB cable combo is working the best for you on the same device. Start the app and wait ca. 10 seconds ("measuring" is on the display). After this time, the charging or discharging current will be shown.
Background info:The app measures the charging/discharging current of the battery. If your phone is not connected to a charger, you see the discharging current which is negative. If you connect a charger then the current what the charger gives will be used to supply your phone and the remaining power will be charged into the battery.
If your phone consumes 300 mA without a charger connected (-300mA on the display), then a 500 mA charger will charge your battery maximum with 200 mA current (200mA on display).
Technical info:The displayed current is an average value from 50 measurements minus the 10 upper values and the 10 lower values. The displayed current can be shaky or unstable or even zero which means, that the Android system provides unstable values. Every company uses different battery types and other hardware making it difficult to get accurate results about your charger.
LiPo batteries don't draw the maximum for the full time it takes to charge the phone. If your battery is charged almost full then the charging current will be much less as by lower battery levels.
Ampere Pro 3.20 Final / Mirror / Mirror
Ampere Pro 3.08 Final APK [6MB] / Mirror / Mirror