USB port vs. 12V DC power for charging iPhone 7 and Kindle

I understand that the Qi charging pad doesn't work for iPhones. Which provides the quickest / most efficient charging for an iPhone 7 or Kindle, the USB port or one of the 12V outlets?

Thanks.

 

I have a cigarette lighter adapter for my iphone that chargers very quickly. I wouldn't recommend the USB for a fast charge. If your using GPS on your phone for example while charging USB, your battery will still drain, just slower than without USB.

 

Isn't the USB port limited to 5 Watts? My understanding in that an iPhone 7 can draw up to 10 Watts while charging, so a 12 V adapter that can deliver 10 W or more will be the fastest charging method.

 

The USB port wasn't designed for charging phones(some phones do some don't) it was for attaching a usb stick or ipod for music.

The 12v outlet will be your best bet and 100% faster than the built in USB port

 

You can also add a Qi case to your phone and use the pad.

iPhone 7 Plus Case, Nillkin [Magic Case Series] QI Wireless Charging Receiver Case Back Cover [Compatible with Nillkin Car Magnetic Wireless Charger] for iPhone 7 Plus - Black

https://www.amazon.com/Nillkin-Wireless-Charging-Receiver-Compatible/dp/B01MDTAPY1

 

i did this and it worked great, but i'm getting an 8 this week which will work with the Qi!!! So pumped!

 

As has been said... the USB ports built into vehicles these days are not high power charging ports. Most only support about 1A or less (that's 5W or even less), so you'll get a slow charge out of it, but that's it.

A good 12V USB charger will do a lot better, depending on the brand and its output of course.