Spring 2017 Mini Pathfinder Motor no Load Current and Voltage Test
By: Moses Holley (Electronics and Control)
Introduction
In this test, I will be testing the n20 motors at various voltages. The motors are rated for 6 volts, but the operating boosted voltage on the 3Dot board is 5 volts. The battery is rated at 3.6 volts, should we tap directly into the battery, but is typically fully charged at 4.2 volts [1]. The discharge cutoff voltage is at 2.75 volts, but wanted to test it at a slightly higher output of 3 volts.
Figure 1. Applying Voltage to the Motor
Results
Figure 2. Voltage and Current Results
Conclusion
There is no significant change in the current draw from the different voltages on all the motors. Since the 3Dot motor connectors will use the 5 volts from the boost converter, we will most likely utilize the same voltage output so that all the motors will spin at the same rate. This is an easier solution than programming the onboard motors to spin at the same rate that the other motors.
References
[1] http://www.batteryspace.com/prod-specs/1389-RCR123A36.pdf