If your e-cigarette flashes when you press the power button, it indicates that the battery is low. You will have to recharge it! If you do not have a screen, your electronic cigarette will flicker and will not produce as much vapor as when fully charged. While charging, the light on your Vuse ePen will display the following light, depending on the current charge level of the battery. Red light: Your battery is charged or drained to less than 10 %. Steady red light: Your battery is between "almost empty" and about "2/3 of its charge".