This is a power board that uses 3 Ni-Cad batteries.
A first battery is used separately to control the boards consuming low(er) power, such as the E128 and the sensors boards.
A voltage regulator with 1A sourcing capability is used to convert the 7+V of the battery into a steady 5V supply to the sensors board.
A second battery supplies power to the servos and DC shooting motor board.
A third batteries in series raises the voltage to 14.4V, where the two h-bridges controlling the DC drive motors will be powered.
NOTE: battery grounds were connected together. All other board grounds were connected together. The kill switch simply serves to connect both ground rails.