120 Watts and 7.2 Volts, how many Amps?
The calculations you did are right. But, the value is the peak power. Your motor will draw power according to the motor controller setting and load.
Keep in mind when the motor is not moving, its resistance is equal to the wire resistance which can be less than 0.1 ohms; essentially a short circuit. That is the reason for the initial &quot;spike&quot;. When it starts rotating the back emf comes into play and changes the effective resistance which decreases the power draw.