That's because the small battery cable in the trunk won't charge. Because one of the main sources of power for new energy vehicles is the power battery. According to the new energy vehicle, charging needs to be compensated, but in the process of charging, you will find a charging gun with a grounding treasure. The interface may be improperly connected. Unplug and reconnect. You can also use a multimeter to test whether the charging output voltage is normal. If the battery is damaged or aged; If the output voltage is almost zero or too low, the charging circuit is faulty. Just check the little battery cable in the trunk.