Patent ID: 7189125

Claim:
A power supply system for a watercraft propulsion device, the power supply system comprising: a plurality of batteries configured to provide power to the watercraft propulsion device, the plurality of batteries being electrically connected to the watercraft propulsion device; a steering drive unit configured to control directional movement of the watercraft, the steering drive unit being electrically connected to the plurality of batteries and configured to receive power therefrom; a central processing unit configured to control power supply from the plurality of batteries to the steering drive unit and watercraft propulsion device based on the respective input of the conditions of the respective batteries; and a power supply circuit that receives power from the plurality of batteries through an independent line from each of the plurality of batteries and provides information concerning the conditions of the respective batteries to the central processing unit; wherein the system is configured such that power is supplied to the steering drive unit and the propulsion device by a first battery until the power of the first battery falls below a specified level, whereupon the central processing unit instructs the system to switch supply of power to the steering drive unit and the propulsion device to a second battery, thereby permitting the first battery to be recharged.