Portable media player

Want Fast Charging? Don’t Use Your Car’s USB Ports

If you have a relatively new car, it probably has a USB port in the dashboard, glove box, or center console. So naturally, you should just use them to charge your devices, right? Not so fast: if you want speedy charging, those built-in ports just don’t cut it.

Unfortunately, the built-in ports in your car are pretty anemic when it comes to amperage. As we discussed in detail in our guide to choosing a USB charging station for your home, amperage is king. The lower the amperage, the longer it takes to charge a device (and the more difficult it is to maintain a charge if the device is in use). The higher the amperage, the faster you can charge your device (and keep it topped off while using it).

The problem with built-in automotive ports is that they don’t deliver enough juice to keep modern power-hungry phones, tablets, and other devices on and charging. We measured multiple vehicles with a USB voltage/amperage meter and found that the data port in the dash (commonly used to hook up a USB drive or phone to play music) offered a very weak 0.5A output. While that’s enough to power up your USB drive full of MP3s, it’s barely enough to trickle charge an iPhone and maintain the current battery level—if you’re using the phone for navigation, a notorious battery hog, it’s…