A:Answer Produces only 5 volts because it's an USB charger which converts the 12v of your car to 5v for your phone. It has enough watts to rival your home charger but not enough to be considered a fast charger, it does well enough thou.
Something like 1.4 amps per usb port if I remember correctly, so about 7 watts per usb port and 21 watts total. By comparison a super fast charger can do double of that or more per single usb port. Those tend to get pricey.
The faster the phone charges the faster the battery heats up and reduces the working lifespan of the device. Something to keep in mind when shopping for a charger and how you plan to use it.
