A powertrain system includes an engine coupled to a turbocharger and a timer, a motor generator coupled to the engine and a battery, and a controller. The controller is structured to receive data indicative of a state of charge from the battery, determine whether the state of charge is at or below a high predefined threshold, modulate control on the engine and the timer in response to determining the state of charge is above the high predefined threshold, determine whether the state of charge is above a low predefined threshold in response to the state of charge being at or below the high predefined threshold, and modulate control of the engine and the timer in response to determining the state of charge is at or below the low predefined threshold.