Ampere

This app allows you to measure the charging and discharging current of your battery. It has PRO features such as widgets, notifications, and alerts on both the device and Android Wear. However, not all devices are supported due to a lack of appropriate measurement chip or interface. Please refer to the list of unsupported phones at the end of the description.

The app is not meant to be extremely accurate, but rather to help you evaluate which charger and USB cable combination works best for your device. It takes about 10 seconds for the app to start and display the current.

The current shown is affected by various factors such as the type of charger, USB cable, phone model, running tasks, display brightness, WiFi and GPS state. It is not recommended to use the readings as concrete science, but they can be used to compare different chargers and cables on the same device.

If the app constantly shows 0mA, you can try using the "Old measurement method" in the settings. This forces the app to use the old measurement interface, if your Lollipop device has one.

Some Samsung devices may not provide accurate values, only showing the maximum possible charging current with the current charger and USB cable configuration. This is a firmware issue.

The app measures the charging and discharging current of the battery. When the phone is not connected to a charger, the displayed current will be negative, indicating the discharging current. When a charger is connected, the current provided by the charger will be used to supply the phone and charge the remaining power into the battery.

The displayed current is an average value from 50 measurements, with the 10 highest and 10 lowest values excluded. It may be unstable or even zero, which is due to the Android system providing unstable values. Different companies use different battery types and hardware, making it difficult to get accurate results about your charger.

LiPo batteries do not draw the maximum current for the entire charging time. As the battery gets closer to being fully charged, the charging current will decrease. A graph and tutorial explaining LiPo charge stages are provided in the app description.

The app may only work with certain phones and ROMs if the "Old measurement method" is turned on and the correct "Measurement interface" is selected. Some phones and ROMs have been reported to not work with this app, and users are asked not to give a wrong rating in these cases. If the app does not work on your device with a pre-Lollipop Android version, please refer to the XDA developer forum thread provided in the description.