There is also a power supply on the car, which we call constant power, namely KL30, which is directly connected to the battery through the fuse, without any control, and will always have electricity unless the battery is removed. Friends who have been engaged in passenger cars may not know that there are two kinds of constant electricity for commercial vehicles. One is the same as passenger cars, which is directly connected to the battery; the other is constant electricity at the main gate. The gate has electricity. Of course, the main brake must be turned off after parking, otherwise it may not start the fire next time.