Techniques to regulate charging with an alternator and a battery to minimize vehicle fuel consumption

A charging control method for a vehicle including an engine that drives an alternator configured to charge a battery of the vehicle, the method comprising:

• modeling, by a controller of the vehicle, a fuel consumption of the alternator for each load level across a range of alternator loads using an engine torque model and a set of operating parameters of the engine;
• determining, by the controller, an energy output from the alternator for each load level across the range of alternator loads;
• calculating, by the controller, a cost-to-charge metric based on the modeled alternator fuel consumption and the determined alternator energy output for each duty cycle across a range of duty cycles of the alternator;
• determining, by the controller, an optimal cost-to-charge from the calculated cost-to-charge metrics;
• determining, by the controller, a target cost-to-charge metric based on a state of charge of the battery;
• and
• operating, by the controller, the alternator at an optimal duty cycle corresponding to the optimal cost to charge, a target duty cycle corresponding to the target cost to charge, or zero duty cycle based on whether current engine operating conditions are indicative of a higher efficiency optimal cost zone for the engine or a lower efficiency target cost zone for the engine.