Random and occasional charging stop is a "ghost question" that cannot be answered in one sentence. To sort it out, there are several possibilities:
1. Power grid factors
1.1. The power grid voltage fluctuates greatly. For the on-board charger (OBC), it exceeds the working range of the input voltage, triggers the overvoltage or undervoltage protection and cannot be automatically restored.
1.2. The cable route from the secondary side of the 10kW/380V power transformer is too long, resulting in a "weak power grid" effect. The control loop parameters of the OBC cannot match certain weak power grid conditions. The loop oscillation will cause the input current to oscillate, triggering the input overcurrent protection of the OBC.
2. Ground wire interference
The vehicle body ground and the PE ground of the power grid are connected through the PE copper pins of the charging gun head and the gun holder, and the PE ground of the OBC is connected through the vehicle body ground and the PE ground of the power grid. If there are many high-power devices connected to the PE ground of the power grid at the same time, a lot of noise signals will be coupled to the PE ground. In layman's terms, "the ground is very dirty". This dirty PE ground will greatly interfere with the detection of CP and CC signals of OBC and AC pile, and may also cause abnormal CAN communication inside OBC.
3. Connection problems between the charging connector head and the connector seat
3.1 There is an abnormal connection between the power part of some vehicle sockets and the charging gun head. After a long charging time, the local temperature of the vehicle plug gun seat is very high, which may trigger the vehicle socket temperature protection and the vehicle will stop charging actively. When the weather temperature is low or the charging time is short, this phenomenon will not occur. It will only occur when charging for a long time at high temperature.
3.2 There is an abnormal matching between the CC and CP pins of the gun head and the hole structure of the CC and CP of the vehicle socket, resulting in poor contact. When the gun is shaken or the vehicle oscillates, the signal connection is disconnected, and the vehicle stops charging actively. It is necessary to increase the length of the CC and CP pins to be compatible with various vehicle plug gun seats.
4. Misoperation of leakage detection
Misoperation of leakage protection circuit breaker is a common problem of circuit breaker tripping. Some AC charging piles have an onboard leakage detection circuit designed inside the charging pile, which may also cause inaccurate leakage detection.
5. Human factors
During charging, someone manually presses the stop button of the charging pile, but does not realize that this button will cause charging to stop. During charging, someone manually presses the S3 switch on the charging connector head, and the vehicle detects that the CC resistor is in a semi-connected state, and the vehicle actively stops charging.