Controlling electrical access to a lithium battery on a utility vehicle

A method of controlling a utility vehicle, comprising:

• storing electric power in a lithium battery of the utility vehicle;
• operating a motor controller of the utility vehicle in a normal mode in which the motor controller provides electric power from a lithium battery of the utility vehicle to an electric motor of the utility vehicle to turn one or more ground engaging members of the utility vehicle, and
• after operating the motor controller in the normal operating mode, operating the motor controller in a walkaway mode in which the motor controller configures the electric motor to provide braking torque;
• wherein the motor controller is constructed and arranged to enter the walkaway mode when a keyed switch of the utility vehicle is set to an OFF position, the keyed switch being electronically coupled with a battery management system (BMS) of the lithium battery;
• and
• wherein the method further comprises:
• tracking vehicle idle time while the keyed switch is set to the OFF position;
• and
• outputting a sleep event signal to interrupt power to and disable the motor controller when the vehicle idle time exceeds an idle time threshold.

A motor controller, comprising:

• a lithium battery interface;
• an electric motor interface;
• and
• controller circuitry constructed and arranged to operate in (i) a normal mode in which the controller circuitry provides electric power from a lithium battery coupled with the lithium battery interface to an electric motor coupled with the electric motor interface to turn one or more ground engaging members, and (ii) a walkaway mode in which the controller circuitry configures the electric motor coupled with the electric motor interface to provide braking torque;
• wherein the controller circuitry is further constructed and arranged to enter the walkaway mode when a keyed switch of the utility vehicle is set to an OFF position, the keyed switch being electronically coupled with a battery management system (BMS) of the lithium battery;
• wherein the controller circuitry is coupled with a timer circuit constructed and arranged to (i) track vehicle idle time while the keyed switch is set to the OFF position and (ii) output a sleep event signal to interrupt power to and disable the motor controller when the vehicle idle time reaches an idle time threshold.