UPair One Intelligent Flight Battery 5400 mAh Rechargeable Battery Use with UPair One 2.7K/2.7K Plus Drone and UPair One Plus 4K/4K Drone. Drone Battery Type: Lithium Battery / Voltage: 11.1V / Capacity: 5400mAh. High battery capacity for up to 18 minutes of flight time with one single charge. Four leds on the flight battery display both the status and the remaining power of the battery. Note:We do not recommend charging the flight battery and remote controller battery with our charger at the same time, otherwise the charger may overheat.