I have the same problem... it is not the battery... it is the 5in1... it is sensing that the battery is drained and going into "protect mode" (flashing the light and reducing the blade spin). If you bring it down for a landing, let it sit for a second or two, you will be able to fly again for several minutes until it happens again. If it keeps happening, then the battery is truly near its safe discharge level and should be placed back in the charger for charging.