↓ 1 callersFunctionlib_battery_level_percent_alkaline_9_voltThe discharge curve for 6x Duracell Alkaline DC AA. It is non-linear.
Source:http://www.powerstream.com/AA-tests.htm
In this model it is split into
libraries/BLE/examples/ble_heart_rate_template_with_battery_service/lib_battery_level.cpp:51