If you have a standard usb charger, the light on it will turn from red to green to indicate a full charge.
Your e-go will blink several times when it's screwed in to the charger to verify that it has connected to the charger, then the charger light should turn from green to red within one minute to indicate that it has begun charging your
device.
You will know when it is time to charge your e-go when you press the fire button and it blinks rapidly for a short period of time and will not fire.