Hi Rep..
I use a triple USB charge adapter by EasyAcc. Very pleased with it. Bought 2 and use them in the car also. The sockets are rated at 2.4/2.1/2.1A and are protected against over heating, over current and over charging. Bought them from different sources for about £8 ea. Seem to be very well made.
I use it to power an iPad mini, and PAW. Had intended using the third USB to power a Zaon MRX PCAS but will defer this to see how well PAW can resolve "bearingless targets", when the software is released.
Always useful to have a spare USB which could always be used by a passenger or for charging the mobile.
Edited link as follows;
http://www.amazon.co.uk/dp/B00N4K079M