Two wheel cart balancing-Battery Connection

I am currently doing a project on a two wheel cart jus lik the segway. I am using the AXHD100k DC brushless motor from the oriental motors.The rated voltage required by the motor is 24V, i use 2 Np7 12V7AH batteries to power the motor, but unfortunately, the motor controller fused out when i connected the batteries in series to the controller. I dont know why it happened, because i believe the battery alone meets all the specifications of the motor.Is it because there was a large surge of current provided by the batteries to Motor. and also How much current can 7AH battery generate??.... Thank you, would appreciate if some one cold help me out in this yhnx

perhaps you had the polarity backwards, and dont be fooled by low amp/hour ratings. some of the small lead acid batteries can provide a couple hundred amps under short circuits for small periods of time.