A Voltmeter confirms my unit is working as designed/intended.I connected my device on a partially discharged battery and let the unit do its thing for a week.A week later I measured voltage with the unit connected - It was 13.1 VI disconnected unit and measured battery it too was 13.1However I let battery sit disconnected for week and found Voltage had stabilized at 12.56VI am told the above readings are normal for a fully charged 12v battery.I have re-attached the charger and will lit it do its thing for the duration of winter.I am happy/satisfied.