Battery Voltage: 7.4V ; Max Charging Time: 3-6 hours; USB Cable Voltage : 5V
Charging Status: At the beginning, the rightmost light on the battery blinks in blue and when the battery is fully charged all 4 lights turn solid in blue.
Charging Method: Connect the charging cable to PC USB port or a phone adapter (5V, 1-2A)
Holy Stone 2pcs Rechargeable Li-po Battery 7.4V 2500mAh and 2 USB Charging Cables for RC Quadcopter Drone HS100 Black