Fixed faulty voltage calculation from ADC
The voltage was calculated by multiplying the ADC-value with the Voltage/ADC-factor (=3300mV/4096bit) and subtracting an offset (measured during calibration).
By applying different voltages and recording the corresponding ADC-value a slightly different Voltage/ADC-factor (=0.788mV/bit) and offset (=162mV) were found.
