This is easy !

This is easy! Problem is the cable. This should be AWG28/1P+AWG20/2C -cable, if you will charge you tablet by 2A power. If the /2C is over AWG20, etc. AWG28, the resistance in the cable is so high that the voltage will drop under 4V on the other end of the cable. You should also buy a short cable, so the resistance won't be so high. The gauge AWGxx tells the copper wire's diameter. Other possibility is, that you buy a 2A charger with 6V voltage. By that way you may charge you application by 5V and 2A current even through a cheap usb cable.