A:Answer The light will be green for about 3 seconds, then turn off., when you plug it it in. That means it is fully charged. If green light is slowly blinking, that means it is still charging. So you have to keep an eye on the light , and of course, you have to make sure your USB port is powered.
So for example, let's say battery is dead, you plug in to an unpowered USB port, you see no light, now you know the USB port is unpowered, i.e, when plugging in, their is always some light activity.