it seems that the 4 channel motor driver i recently brought seems to have a problem. the 4 channel motor driver is connected to the arduino to control all 4 motor. but when i turn on the arduino with 7V power connected through a buck boost converter while the 12 V is connected to the motor driver both power source originate from the same 12V battery. the motor driver seems to turn on it self even when the switch is in off mode. i even manage to control the motor with the switch in off mode. this did never occur before when i use power bank to powered the arduino while the motor driver is powered by 12V lipo battery. is this normal? need help here.
besides that, the motor driver is connected to a 12V battery with a reading of 12.5V in the input of the motor driver. but the motor driver produced an output of only 10.5V at full speed. is this normal?