Selection of charging modes for autonomous device

A method for charging a rechargeable energy storage unit in an autonomous device having a controller with a processor and tangible, non-transitory memory, the method comprising:

• determining availability of at least one charging station and at least one parking lot through a survey of local charging infrastructure and local parking infrastructure, respectively, within a predefined radius of the autonomous device, via the controller;
• determining if it is cost-effective during an excursion to incur a charging fee at the at least one charging station or incur a parking fee at the at least one parking lot, via the controller;
• and
• if it is cost-effective to incur the charging fee, then selectively employ at least one of a plurality of charging modes, including an open-ended charging mode and a defined departure charging mode, via the controller.

A system of selecting charging modes for a rechargeable energy storage unit in an autonomous device, the system comprising:

• a controller operatively connected to the rechargeable energy storage unit and including a processor and tangible, non-transitory memory on which is recorded instructions;
• wherein execution of the instructions by the processor causes the controller to:
• determine availability of at least one charging station and at least one parking lot through a survey of local charging infrastructure and local parking infrastructure, respectively, within a predefined radius of the autonomous device;
• determine if it is cost-effective during an excursion to incur a charging fee at the at least one charging station or incur a parking fee at the at least one parking lot;
• if it is cost-effective to incur the charging fee, then selectively employ at least one of a plurality of charging modes, including an open-ended charging mode and a defined departure charging mode;
• wherein the defined departure charging mode is employed where a predefined departure time is selected by a user of the autonomous device and includes derating a charging current applied to the rechargeable energy storage unit such that charging is completed at the predefined departure time;
• wherein the controller is configured to employ the open-ended charging mode where no predefined departure time is selected and the open-ended charging mode includes:
• when the state of charge reading is in the predefined first window, employing a predetermined relatively high charging current;
• when the state of charge reading is in the predefined second window, employing a predetermined relatively low charging current;
• and
• when the state of charge reading is in the predefined third window, employing an approximately zero charging current.