I need to power a MAX9814, DFPlayer Mini and a MicroSD Card module. I am afraid that the 5v pin is not enough so I stripped a USB cable, took the ground cable and connected it together with the arduino gnd, and power those three devices with the 5v cable from the USB I stripped. It works just fine but I am looking for a definitive way to do it, without a breadboard, so I will use a phone charger like the one I posted originally. What do I need to know in terms of amperage? Can I connect the arduino to the 5v 2.1A port or should i do it with the 1A? If I use the arduino with one port, the other will be for the USB power supply, will it work either way with 2.1A or 1A depending on which one the arduino needs?