The charging speed of the car charger is related to its output current and output voltage, in general, the car cigarette lighter interface can provide 12V or 24V voltage, and the car charger can convert it to 5V, the current of the ordinary car charger is about 5V\/1A, and the fast charging function can reach 5V\/2A, or even 9V\/2A, the charging speed is quite fast.
Car charger more than 2 amps is really fast.