Using two motors with H-bridge

Hey! I have connected two dc motors to a H-bridge and connected it to the Arduino Uno. When I connected the arduino to a battery, motor 1 moves faster than the other one. I interchanged the motors on the H-bridge and now motor 1 is moving slower compared to the other one. I can't figure out why this is happening :confused:

Do you mean a motor shield? IE two H-bridges, one per motor.

Perhaps one channel is damaged, perhaps its being driven differently (you havenโ€™t
posted your code).

Full details of the motor driver board and how its connected would be good.