Just bought a Mustank 2100 HP at local smoke shop nearby. It has been on the charger for 9 hours and is still blinking from red to green. Its the screw on usb charger that is plugged into a wall charger. The button is this pinkish/purple color when plugged in and when the tank is unscrewed. If I take it off the charger and try to use it with the tank fully screwed on the light flashes red when I try to do anything. Do these tanks take this long to charge? Or do I need to get a different usb charger for this certain battery? As far as I knew the usb screw on chargers were universal. Just getting antsy! Please help me