Tuesday, February 22, 2011
Battery life: stress test
The above graph represents the voltage of the motor battery vs. time.
chassis suspended so the wheels do not touch the ground
motor power set to 150 units greater than stop condition
allowed to run without external torque on wheels
A natural exponent function very nearly represents the data, and establishes a horizontal asymptote at 11.26 volts.
It is reasonable to assume that the battery should never be allowed to approach that voltage, as it may refuse to take a charge afterward.
20 minutes of navigation seems to be the limit for safe operation.