I drive a GMC Acadia that has a built-in entertainment system, so my sons can watch DVDs when we're driving on trips of more than an hour. This was a great purchase for them. It also gives me an 110 Volt AC outlet which I can use to charge an iPhone using the standard iPhone adapter. However, the outlet has relatively low power output, so charging takes a pretty long time.
The workaround for this was to purchase a car charger that works with the 12V DC outlet, which has the potential to work faster.
When I first wrote this article, I recommended the Incase High Speed Dual Car Charger. This was a device that charged two iPhone 5s smartphones faster than the standard iPhone charger does when connected to my SUV's AC outlet.
Our current recommendation is the Anker Quick Charge 3.0 39W Dual USB Car Charger. This charger is even faster than the Incase High Speed Dual Car Charger and uses the fastest charging modes supported by Apple, Android devices made by Samsugn Galaxy, LG, HTC, Sony, Nexus, and Motorola. These modes are Quick Charge 3.0, PowerIQ, and VoltageBoost.
I've recommended the Anker Quick Charge to friends because it does such a good job at rapidly charging one or two iPhones. Some people look at Amazon.com's vast selection of 12V USB chargers and choose a less expensive model. Please note that some of the 12V USB chargers sold are not sufficiently shielded for Radio Frequency (RF) interference. As a result, they can create a hum that's audible on your car's stereo.