Can a car's USB port directly charge a phone?

[MaliaAnn]

A car's USB port can directly charge a phone, but the charging speed is very slow. While driving, you can simply plug your phone's data cable into the USB port for charging. The USB port in a car provides direct current (DC) power, which is supplied directly by the car's battery. Since mobile phones also use DC power for charging, the car's USB port can directly charge the phone. However, due to the low voltage of the car battery, the charging speed tends to be relatively slow. Car USB ports are designed as accessories to allow car owners to conveniently charge digital devices anytime using the car's power supply. They can be used to plug in USB drives for playing music, serve as USB car cigarette lighters, function as car vacuum cleaners, or power devices like electronic dog detectors and dash cams. Some high-end cars typically come with two USB ports, enabling simultaneous charging of two digital devices.