Error one: Car charger output current can not be more than the maximum current of the phone .
The correct one is that the charging current can be more but not less. For example, when an output of 5v / 2.1A car charger is to charge a maximum rated input power of 5V / 1A mobile phone, the current of charging to mobile phone is 1A,and the current of charging to tablet is 2A, it could be full of power in a short time; but if an output of 5v / 0.8A car charger is to charge the same phone, the input is 0.8A, not only just charging slowly , but also It will be over-heating and will damage the phone battery after a long time charging. Therefore, choosing a premium quality and high current car charger is necessary to extend the lifespan of your phone. Generally, the required charging current for the mobile phone including the iPhone is 1A (part 2A), and the tablet computer is generally 2A, so the car charger with multiple USB interfaces must meet these standards.
Error two: There is a USB port on the car, No need Car charger.
There are a lot of cars that come with a USB port, and there may be more than one port. Most people think that charging the phone or any other device with the USB port on the car is fine. In fact, it is wrong, because most of the car's USB interface is set for audio data transmission, so the interface current of some vehicles is far less than 5V / 1A.If you use the USB interface on the car to charge the phone or even the tablet, and the current does not meet the standard, the device will be damaged. In addition, the Android device or iPad will charge for device identification when charging, and each car design is different.
Error three : The more USB ports, the slower the charging speed
The current depends on the voltage. It doesn't depend on the USB interface. Because the current is already divided, it doesn't interfere with each other. If it is slower than the single USB interface, who will buy it? Manufacturers design multiple U ports, mainly to facilitate the owner to charge a variety of electronic products.
However, there are some manufacturers on the market that call low-current car chargers high-current output. Because the higher the current output, the higher the requirements on materials and production processes, the unscrupulous merchants can do everything to save costs. Come out, it is unfortunate to buy it. But at least it is still good to find out early. For those of us who don't have professional test instruments, we can only observe the car charger that we bought. If we charge the phone and tablet at the same time, it is slow and very hot. That is, the current is not up to standard, it is best to change it quickly. I don't have these problems with the 3USB interface car charger I use.