I have a " courier charger" for plugging a USB to mini USB cable into that goes directly into AC plug. This is what the label says:

input:100-240V/AC 50/60Hz 150mA output: 5.0V -500mA+ or - 50mA


is this "safe" to charge my Ben with? 


I have an AC inverter running off of a 12V battery which I charge with a 60W solar setup


thanks

-jain