First of all: USB car charger must comply with a principle, for small consumer electronics equipment battery charging, USB port is an economic and practical power supply. To fully comply with the USB 2 specification, the load on the USB port must be able to communicate with the host. The load must also comply with the power management requirements, including low-power mode, as well as easy for the host to determine when the need to absorb large current from the port means. Although partially compatible systems can be adapted to most USB hosts, unexpected results can sometimes occur. Only a good understanding of the requirements of the USB specification and the load can be achieved in a good balance between the compatibility of the specification and the complexity of the load. So USB charging, from the interface to the voltage conversion, and the current power requirements match the needs of electrical appliances. Sometimes you will encounter your purchase of USB can not give your electrical charge, so there may be a matching problem. For example: do you use the electrical voltage is USB charging DC 5V voltage. If the voltage is correct, it is possible that your electrical power may be larger. USB car charging power may not match, there may be no charge, or charge less than electricity. Then it is necessary to confirm whether the current charge is less than a match.
USB based on the above factors: it is the first car in the power DC 12V or DC 24V into DC 5V; then the DC 5V output using USB unified interface to charge to the corresponding electrical. Based on different electrical power, USB car charging power is also different, the main difference between the current USB car charging less.Back