The car pulse charger fan turns and stops for a while, because when the circuit detects that the battery is full, there is a green light, stop charging, and the fan stops rotating, but the chemical balance will be left at this time, the battery voltage will be more and more decreased, and the circuit will re-control the charging green light will no longer light up the fan and start to turn. And so on. Until it is full, the green light will no longer change.
This phenomenon is caused by the charger fan itself. It may be that the connection line is in poor contact, resulting in time off and on, and the solution needs to check the circuit.
Another possible cause is the wear caused by the lack of oil in the bearings at both ends of the fan, and the solution is to fill the lubricating oil or replace the bearing.