Battery Ammeter is an Android application developed by Herald. It falls under the category of Utilities & Tools and is available for free. With Battery Ammeter, users can measure the charging and discharging current of their device's battery.

Not every device is supported by Battery Ammeter, as some lack the necessary measurement chip or interface. However, for supported devices, the app provides valuable insights into the charging and discharging performance. It allows users to evaluate which charger and USB cable combination works best for their specific device.

The current flow is influenced by various factors such as the type of charger (USB/AC/Wireless), USB cable, phone type, current tasks running, display brightness, WiFi state, and GPS state. It's important to note that the app's readings should not be considered as concrete science, but they are sufficient for relative comparisons of different chargers and USB cables on the same device.

Battery Ammeter measures the charging and discharging current of the battery. When the phone is not connected to a charger, the app displays the negative discharging current. On the other hand, when a charger is connected, the charger's current is used to supply the phone while the remaining power is charged into the battery.

The displayed current is an average value derived from 50 measurements, with the 10 upper and lower values excluded. It's worth mentioning that the displayed current may sometimes be shaky, unstable, or even zero due to the Android system providing unstable values. Additionally, since different companies use varying battery types and hardware, obtaining accurate results about chargers can be challenging.

Battery Ammeter is a helpful tool for users to assess the charging and discharging performance of their device's battery and determine the most effective charger and USB cable combination.