My brick was previously under-reporting the measured voltage. To investigate this, I have probed some pads on the PCB with a multimeter and got these results:
battery voltage ... 8.25 V voltage at ADC pin ... 2.06 V (OK, voltage is correctly divided by 4) ADC ref. voltage ... 3.2 V ADC measurement ... 42122 (OK, range is uint16_t, this result corresponds to cca. 2.06 V)
This PR updates the constant to reflect this. However, I'm a bit concerned about the old
ADC ref = 3.05 V value - is that one correct for the other brick?