On Fri, 31 Jan 2014 08:13:23 +0000, Danny D'Amico wrote:

Googling some more, it seems the most the Samsung Galaxy S3 will every
draw is 900 mA

It seems, that in the car, the problem is that we probably shouldn't
use Apple USB chargers, unless we use special cables:

At least that is what is implied he
http://forums.androidcentral.com/sam...harger-us.html
Apples 10W/2A charger puts 2.8v on one of the data lines and 2v on the other
(I forget which is which) to tell an iPad that it can pull up to 2A.
Earlier iphone/ipod wall chargers put 2v on each data line which will
limit the device draw to 500mA. This is why you need to use a "charging cable" with
wall/car chargers made for apple products. The Apple oriented chargers do not
internally short the data lines so most android phones will treat it like a 500mA
source. The charger that ships with your android phone has the data lines shorted
internally so it doesn't matter what cable you use.