I have a http://www.amazon.com/gp/product/B004QOAGOQ/ "4-port USB charger". Recently I noticed that some Android devices e.g Nexus 7 (2013), charge very slowly when one particular micro USB cable is connected but that same cable charges other devices just fine.
I am not sure what to make of this. I thought a cable functions in a binary fashion i.e. it either works or doesn't. Why would it have a degraded performance just in some situation? As long as the connection on both ends is proper so the current is flowing, that's all that matters, right?
Is there a app to check how much current/wattage is currently being received by the Android device? I tried "Battery Monitor Widget" on the Play Store and it shows the current flow as negative or 200mA, surely that can't be right when the charger is putting out 5V/1A per port. Maybe the app is buggy.