Hungry Devices

I never understood why we need to buy additional USB adaptor and cables to charge phones, now I have Paddy and an S4, I start to understand.  The bog standard charger can be less than 1A, and that is insufficient to inject power into the battery.  So new device needs minimum 2A output to charge into the device.  I also suspect the cheap USB cables I got are useless!  I must check out all my adaptors and cables and see how to assign them to my travels.