Patent ID: 6987376

Claim:
A marine propulsion system comprising: an engine configured to be supported by a hull of a watercraft and capable of mechanically powering a water propulsion device to propel the hull through the water; a generator coupled to the engine to provide power to a battery configured to provide power to a starter motor to initiate engine operation; and a battery monitoring system capable of replenishing a charge in the battery when the charge falls below a first predetermined value, the battery monitoring system including: an integrating unit that integrates current extracted from the battery and current provided to the battery to provide a signal indicative of a net integrated current value, a charge determining unit responsive to the signal indicative of the net integrated current value, the charge determining unit providing a first output signal when the charge in the battery has fallen below a first predetermined value, and an engine control unit responsive to at least the first output signal from the charge determining unit to automatically start the engine when the charge determining unit determines that the charge in the battery is less than the first predetermined value, wherein running the engine causes the generator to provide electrical current to charge the battery.