Power supply system for vehicle

A power supply system for vehicle comprising:

• an A.C. generator having a rotor equipped with a field coil and an alternative field coil;
• a high-voltage battery that has an electrical connection with the A.C. generator and is charged by the generator;
• a low-voltage battery the voltage of which is lower than that of said high-voltage battery;
• a DC/DC converter that steps down the voltage of said high-voltage battery and supplies the lowered voltage to said low-voltage battery;
• and
• a control means for charging said low-voltage battery with the electric power generated through said alternative field coil in said A.C. generator when said field coil is not energized.

A power supply system for vehicle comprising:

• an A.C. generator having a rotor equipped with a permanent magnet and a field coil;
• a voltage step-up means which steps up output voltage of the A.C. generator;
• a low-voltage battery which is charged with the voltage stepped up by said voltage step-up means;
• and
• a control means for charging said low-voltage battery with the electric power generated through said permanent magnet in said A.C. generator when said field coil is not energized.