Lipo battery voltage to % remaining

[patfelst]

Hi Volos, I'm not sure if AXP192 provides remaining battery charge, but I use this formula for estimating % remaining as a function of measured battery voltage. So you can pass this to the function below M5.Axp.GetBatVoltage();

/*
-----------------
  Returns the estimated battery capacity remaining in a LiPo battery based on its measured voltage
  According to:
    Percentage = 123 - 123 / POWER(1 + POWER(Voltage /3.7, 80), 0.165)
-----------------
*/
uint8_t lipo_capacity_percent(float voltage) {
  float percent = 123.0 - (123.0 / pow(1 + pow(voltage / 3.7, 80), 0.165));

  if (percent > 100.0) percent = 100.0;
  if (percent < 0.0) percent = 0.0;
  return (uint8_t)(round(percent));
}