Hey there Wong KC,

1. Plugging your phone into a car's USB port could damage the charger, resulting in inconsistent power supply to the device.

2. It may not be harmful for new cars with healthy batteries, but it would affect cars of older models.

3. If your smartphone is charged up at “cigarette lighter” port, it could receive too much power. The excessive power could cause malfunction or damage to the charger.

You can read these articles to find out more:

- https://www.businessinsider.com/should-i-charge-my-phone-in-my-car-2017-10#:~:text=MosayMay%2FShutterstock%20The%20INSIDER%20Summary,if%20it's%20an%20older%20model.

- https://time.com/4023751/phone-car-charger/