If the Mi 9 balance car cannot be charged and the charger shows a green light instead of a red light, it may be due to the following reasons:
1. The charger is faulty. Replace the charger.
2. The charging cable is loose or damaged. Replace the charging cable.
3. The battery is faulty and needs to be replaced.
4. Balance the internal circuit of the car, it is recommended to contact after-sales service for maintenance. Before fixing the problem, make sure the charger and charging cable are working properly, check that the battery is properly installed, and try to use another power outlet for charging. If the problem persists, it is recommended to contact Xiaomi after-sales service for further help and support.
If you have confirmed that the charging port and the charger are tightly connected, and you have tried to replace the new charger, but the problem is still unresolved, then there may be a problem with the battery of the balance car.
In this case, it is recommended that you contact Xiaomi's after-sales service for consultation and maintenance. Xiaomi's after-sales service will help you solve the problem, including checking whether the battery is damaged, whether the battery needs to be replaced, etc. Please be careful not to attempt to disassemble the balance car for inspection or repair, so as not to cause more serious damage.