The Hobbywing SeaKing 4685SL V2 900KV delivers sensorless brushless power for electric RC boats. Its water-cooling jacket helps carry heat away during demanding runs, while the black CNC-machined aluminium housing provides a durable motor assembly.

Features

• 900KV winding for 6–14S LiPo operation
• 4-pole sensorless brushless design
• Water-cooling jacket with circulation channels and external cooling fins
• High-temperature windings and precision bearings
• 5mm output shaft

What’s Included

One SeaKing 4685SL V2 900KV motor with water-cooling jacket and motor leads.

Compatibility

Hobbywing recommends this motor for RC boats up to 140cm long and pairs it with the SeaKing 200A HV V4 ESC. Use a 5mm motor-shaft coupling and a marine brushless ESC supporting the chosen battery voltage. The 6–14S motor rating applies alongside the ESC’s own voltage limit.

Installation

With the battery disconnected, secure the motor to its mount and align the shaft coupling. The mounting pattern is 4 × M4 and 2 × M3, with 7mm-deep holes; account for the mount thickness when selecting screw length. Connect the three motor leads to the ESC and secure the water-cooling hoses with clamps or ties. To reverse rotation, disconnect power and swap any two motor wires, or use the ESC’s motor-direction setting. Confirm cooling-water flow during operation.

What battery range does this version support?

The 900KV 4685SL V2 is rated for 6–14S LiPo. The chosen battery must also be within the ESC’s voltage rating.

Is the water-cooling jacket included?

Yes. The motor comes with its water-cooling jacket, ready to connect to the boat’s cooling circuit.

Does it need a sensor cable?

No. This is a sensorless motor and connects to the ESC through its three motor leads.

What size shaft coupling does it use?

The motor output shaft is 5mm in diameter. Use a coupling with a matching motor-side bore.

Is an ESC included?

This listing is for the motor. The ESC, battery and boat installation hardware are separate.