The Power Bank holds 1200 milliamps. It takes about 2 hours to fully charge the Power Bank. Once the charge cycle is complete, the LED will turn from Red to Blue to indicate a full charge. The Power Bank unit can not be overcharged and there is a built in safety system to monitor if the units charging cycle has gone over the recommended 2 hours.
The Power Bank has no indicator on it to indicate the level of power remaining during normal use. You should get on average about 13 flights with a fully charged unit so counting your flights is the best way to monitor the power level during use and to gauge when its time to re-charge.