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My brand new pair of bluetooth headphones stopped working after charging them with a 2.1 Amps USB outlet. I can't turn it ON anymore. I do see the LED battery Green then I charge it though. I noticed on the datasheet that the Amps for the headphones are 500mA and I've been charging them with my 2.1A usb plug. Could that have friend the circuitry? I'm not sure how battery works, for from Ohms law, IR=V if V is constant 5V, and R I'm guessing is too, then A could not vary.