It can be recharged by any USB port,without needing or carrying an external charger.

AA model specification as follows:

Norminal Voltage: 1.2V

Typical Capacity:  1 450mAh

Recommended Discharge: 1 000mA

Discharge upper limited: 4 350mA

Charge Time: 5-6 hours (charge with computer USB port)

The indicator light shine all the time when charged, and turn off automatically when charge full. 

lt can be recharged about 500 times in three years.