You know what’s annoying? When you plug your smartphone into your car’s USB port and it doesn’t charge. Has this happened to you? Kims No Bull of Laurel, MS, a local Chrysler, Jeep, Dodge, Ram, Toyota, Nissan, Chevrolet dealer sells a lot of cars so they hear about this often. Well, here’s the reason why: not all car USB ports are designed to charge phones, or even power any peripheral devices at all. They are simply there to transfer data to the car’s infotainment system, not to charge anything.

There’s a few other things that can prevent your phone being charged too. For example, there’s also a chance that there is a compatibility issue between your car’s USB port and your phone, or there might even be an issue with your cable. Lots of things can prevent your phone from charging. Here’s what you need to know:

Two types of USB ports

When the USB port and cables were first introduced in 1996, the initial standard specified two different versions of USB ports: data ports and powered-data ports. USB data ports only transmit data back and forth between devices, while powered data ports transmit both data and power.

USB Data Ports in Cars

Data ports typically allow you to plug in a USB flash drive, smartphone, or MP3 player to listen to music. Since this type of port only uses the data connection terminals of the USB connector and not the power terminals, it isn’t going to charge your phone.

By the way, if you are unsure whether or not your vehicle has a data-only USB port, and it doesn’t say one way or the other in your owner’s manual, the easiest thing to do is plug in a device and simply see if it shows that it’s charging.

USB Powered-Data Ports in Cars

The USB port on your dash may be both for data and for power. The data is routed to your car’s infotainment system and the power is used by the connected device. In the case of a cell phone, the power will be used to power (or charge) your phone.

USB Data Cables Versus Charging Cables

Like USB ports, there are different types of USB cables. If you look closely into the end of a USB connector, you will see four terminals. Terminals one and four transmit power, while terminals two and three transmit data. Data-only cables omit terminals one and four, and power-data cables have all four terminals.

So, How Do I Charge My Phone?

If your phone isn’t charging in your car:

1. The first thing you need to verify is that the USB port you are connecting to is a power-data port.

2. Next verify if the cable you are using is a data-only cable (look in the connector end for all four terminals. If it is, you won’t be able to charge your phone.

3. If your car recognizes your phone and connects it in media player mode, there is a chance that the USB port is supplying power but the charging amperage may not be high enough to charge your phone.

Work Around

If you still can’t get your cell phone to charge, here is an easy work around: buy a 12V cigarette lighter adapter with a USB port on it and use that!