An example of a vehicle electrical system includes a rechargeable energy storage system (RESS) having a first voltage and a power inverter selectively connected to the RESS. The system further includes an electric motor having a plurality of machine windings with each of the machine windings including a polyphase terminal electrically connected to the power inverter. The machine windings further include a neutral terminal separate from the polyphase terminals and configured to electrically connect to an off-board power source having a second voltage that is below the first voltage of the RESS. The power inverter is configured to cycle between first and second operational states, such that the power inverter and the electric motor steps up the first voltage to the second voltage.