How does the automatic battery cut off logic prevent complete battery discharge on ground in the A320? I was reading in the electrical systems of the a320 FCOM and in one of the notes it stated that the batteries have an automatic cutoff logic which prevents them from getting completely discharged when on the ground. (Parking) 

But how does this logic exactly work? As the batteries are permanently connected to the hot bus in which they will continue to discharge
According to this page: http://theflyingengineer.com/projects/airbus-tech/electrical/

A Battery Automatic cut-off logic prevents the batteries from discharging completely when the aircraft is on the groung [sic] (Parking).
Automatic battery contactors open when :

The a/c is on the gorund [sic].
The BAT P/b s/w’s are at AUTO
The main power supply (EXT PWR+GEN) is cut off
Battery Voltage is low.


Nothing should automatically disconnect the batteries from the corresponding HOT BUS, so if something is left on the HOT BUS it would continue to drain the battery.