Patent ID: 7304402

Claim:
A car power source apparatus comprising a driving battery ( 1 ) having a plurality of batteries connected in series, a pair of contactors ( 2 ) to connect contacts to the positive and negative output sides of the driving battery ( 1 ), a switching circuit ( 4 ) to switch the pair of contactors ( 2 ) on and off, and an auxiliary battery ( 6 ) to electrically power contactor ( 2 ) coils and switch contactor ( 2 ) contacts on and off; the switching circuit ( 4 ) is provided with a voltage detection circuit ( 7 ) to detect auxiliary battery ( 6 ) voltage, a series switching circuit to connect coils of the pair of contactors ( 2 ) in series and switch both contactor ( 2 ) contacts on, and a parallel switching circuit to connect coils of the pair of contactors ( 2 ) in parallel and switch both contactor ( 2 ) contacts on; wherein the switching circuit ( 4 ), detects auxiliary battery ( 6 ) voltage via the voltage detection circuit ( 7 ), when auxiliary battery ( 6 ) voltage is higher than a set voltage, it connects the pair of contactor ( 2 ) coils in series to switch the contacts on via the series switching circuit, and when auxiliary battery ( 6 ) voltage is lower than a set voltage, it connects the pair of contactor ( 2 ) coils in parallel to switch the contacts on via the parallel switching circuit.