What battery it using? you can buy it from you local shop.

3.7v 702035  xh2.54 plug

there have two cables, 

one cable for charge

one cable for USB data upload

Must read! ! !

1.During installation, the circuit board must be powered off, otherwise, it may damage the steering gear and burn the circuit board.
2.When installing the servos, be sure to perform the steering gear reset operation. Pay attention to the installation angle of the steering gear. If the steering gear angle is not installed correctly, it will cause the motor to block up, damage the servo or even burn out the circuit board.
3.The steering gear is reset by a power-on. The steering gear should not be twisted by hand, which may damage the steering gear.