Apparatus and method for electrical power management in a vehicle system

An electric power management system for supplying electric power in a vehicle including an internal combustion engine and a generator, comprising:

• a first power bus arranged electrically in parallel with a second power bus between first and second nodes;
• a third power bus electrically coupling a first battery and an auxiliary load at the second node;
• the second power bus electrically coupling an engine starter, a second battery and a generator at the first node, and selectively electrically coupling the first node to the second node when a first switch is activated, wherein the second battery electrically couples to the first node when a second switch is activated and wherein the engine starter electrically couples to the first node when a starter switch is activated;
• the second power bus electrically coupling the first node to the second node when a third switch is activated;
• a controller monitoring states of charge of the first battery and the second battery;
• and
• the controller controlling the activations of the first switch, the second switch and the third switch in response to a preferred operating mode and the states of charge of the first battery and the second battery.