These batteries are the standard packs that come with the Zagi. They arnt very old and dont have many flights on them. They're 8 cell 1700mA NiMh packs. AA size cells. They're 9.6 volts.

This is the same type setup I've been using on it for 6 years and this is the first time I've had a problem with it.

Edit: Forgot to say, this is a brushed system with a 400size motor.