Abstract: The present disclosure relates to a charging control method and system for a marine propulsion device, and a marine propulsion device. The method includes: acquiring a rotational speed and a regeneration charging power of a motor during a sailing process of a vessel; adjusting the rotational speed to obtain the regeneration charging power corresponding to the adjusted rotational speed, and searching for a power extreme point of the regeneration charging power relative to the rotational speed based on a regeneration charging power varying process; maintaining the rotational speed corresponding to the power extreme point to realize regeneration charging of a battery.

Abstract: An underwater propulsion apparatus includes a motor and a control system for controlling the motor. The control system includes a remote controller and a motor driving device, wirelessly communicating with the remote controller. The motor driving device includes a communication repeater module and a motor driving module. The communication repeater module is configured for detecting interruptions or non-receipt of a wireless signal transmitted by the remote controller. Wireless signals to the motor driving module are transmitted by the remote controller to the communication repeater module. The motor driving module is configured for receiving the wireless signal, and outputs a driving signal for driving the motor according to the wireless signal, the motor driving module shutting down when no signal is received.

Abstract: A closed-loop cooling ship propulsion apparatus includes a power device, a pump, and a coolant supply. A fluid circuit is formed in the ship propulsion apparatus and a coolant in the loop can be arranged to circulate through all heat-generating components in addition to the pump and motive power unit. A closed-loop circuit avoids the blockages and contamination which might occur if the water of a sea or lake was used directly.