Power Consumption Theory

by Robert Licari and Anthony Vo

Before we begin it is imperative to note that the power consumption equations calculated are heavily related to the amount of torque required to move the motors from rest to forward motion. In accordance with that idea, the following theory is calculated considering the worst power conservation possible. By that, we mean that there is probably no way that the Rover will draw this much power, but the fact of the matter remains that the equations are scenarios that can, and probably will happen. Our theory at this point considers that these scenarios are happening constantly.

 Having said that, we can do some simple addition in order to compare our power consumption:

 Power_DCMotor + Power_Servos = Motor Power Consumption

 5 W + 3 W = 8 W

 Now if we do a simple calculation involving the current, we can find the total current drop that the Rover will consume:

 8 W = 8.4 V * I_total

 I_total = 0.9524 A

 If our battery output is 800 mAh, then we can easily state:

 Operational Time = 0.8 Ah / 0.9524 A = 0.84 h

 0.84 h ~ 50 mins

Given our simple calculations and considering only the power consumption of the motors itself operating constantly at their rated voltages, we should be able to run the motor for approximately 50 mins.

Bear in mind that this is an ideal situation and is not considering physical constraints and is assuming constant heavily-powered motion from our motors. The reason the calculations were done this way is to illustrate a time that was within our overall assumptions as well as a starting point for the next phase of calculations being the physical constraints of our payload (the rover itself) as well as additional power concerns involving the microcontroller.