Firduo Sea Lion 120A Water-Cooled ESC for Efoil & Hydrofoil

🌊 120A Continuous. Water-Cooled. Built for eFoil.

The Firduo Sea Lion 120A Water-Cooled ESC is a high-current speed controller engineered specifically for RC boat, eFoil, and hydrofoil applications. With 120A continuous / 240A burst (10s) output, active water cooling, and waterproof construction, the Sea Lion 120A delivers reliable, sustained power for demanding water sport builds.

Designed with top-quality electronic components for enhanced current endurance, the Sea Lion 120A features excellent start-up, acceleration, and linearity characteristics. Multiple protection systems — stall, low voltage, over-heat, and signal loss — keep your build safe. Program via LCD Program Card for precise tuning. Available as ESC only or bundled with the LCD Programming Card.

⚡ Key Features

• ✅ 120A Continuous / 240A Burst (10s) — high sustained current for eFoil and hydrofoil motor drives
• ✅ Active Water Cooling — 4.6mm water cooling pipe keeps ESC temperature stable under sustained load
• ✅ Waterproof structure — splash-proof construction with water-cooled heat sink for marine environments
• ✅ 5–12S LiPo Input — wide voltage range compatible with common eFoil battery configurations
• ✅ Bidirectional Forward/Backward — selectable forward-only or forward/reverse operation
• ✅ Multiple Protection Systems — stall protection, low voltage cutoff, over-heat protection, signal loss protection
• ✅ LCD Program Card — easy parameter tuning and firmware updates via multiple methods
• ✅ Excellent Start-up & Linearity — smooth throttle response optimized for RC boat and eFoil applications
• ✅ Compact Form Factor — 105×48×23mm, 230g — fits tight enclosure installations

📋 Full Specifications

📦 What's in the Box

• ESC variant: 1× Firduo Sea Lion 120A ESC
• LCD Programming Card variant: 1× LCD Programming Card (for parameter tuning without PC)

⚠️ No BEC — receiver/remote must be powered separately.ESC's waterproof rating is waterproof-Splash protection; it cannot be used underwater.

🔗 Compatible Builds & Recommended Pairings

• eFoil / Hydrofoil — 120A continuous suits 65111 motor builds at 10S–12S
• RC Boat / USV — bidirectional mode and excellent linearity for precision boat control
• Electric Surfboard — compact 105×48×23mm fits tight waterproof enclosures
• Recommended Motor (2KW): Firduo 65111 150KV IP68 Waterproof Motor — 2KW peak, 10mm shaft, matched for 120A ESC at 10S–12S
• Recommended Motor (6KW): Firduo 65162 120KV 6KW Waterproof Motor — for higher power builds; pair with Sea Lion 200A for full power
• Higher Current ESC: Firduo Sea Lion 200A Water-Cooled ESC — upgrade for 65162 motor builds requiring 200A continuous
• VESC Alternative: Firduo Manatee 100 75V 100A VESC — open-source VESC platform with full telemetry and UART remote support
• Recommended Remote: Firduo VX3 IP67 Waterproof Remote — PPM mode compatible with Sea Lion ESC signal input
• Recommended Connector: Firduo 120A Waterproof Power Connector  —for sealed battery-to-ESC connection.For ESC-to-motor, the Firduo 120A Waterproof Connector is recommended.
• LCD Programming Card: Available as a separate variant ($34) — select "Lcd programming card" above for parameter tuning without a PC

🛠️ Setup Guide

1. Verify voltage compatibility — confirm your battery is within 5S–12S LiPo (18.5V–44.4V). The Sea Lion 120A has no BEC — you must power your receiver/remote separately from a standalone BEC or receiver battery. Do not connect the ESC signal wire to a BEC output.
2. Connect motor phase wires — connect the 3× 12AWG motor wires (160mm) to your motor phase outputs. Rotation direction is set by swapping any two phase wires. Test rotation direction at low throttle before installing the propeller.
3. Connect water cooling — attach the 4.6mm water cooling inlet and outlet to your board's water circuit. Ensure water flows through the ESC before running at high current. Use appropriate barb fittings and secure with hose clamps to prevent leaks.
4. Connect battery — use a high-current connector rated for 120A+ (Firduo 120A–250A waterproof connector recommended). Use an anti-spark switch or pre-charge resistor to prevent connector arcing. Verify polarity before connecting.
5. Connect signal wire — connect the JR male signal wire (white/black, 300mm) to your receiver's throttle channel output. The Sea Lion uses standard PPM signal — compatible with most RC receivers and the VX3 remote in PPM mode.
6. Program the ESC — use the LCD Program Card (available as a separate variant) to set throttle range, drive direction (forward only or forward/reverse), low voltage cutoff, and other parameters. Calibrate throttle endpoints with your remote before first use.
7. Water test at low power — start at 20–30% throttle in calm water. Verify smooth motor operation, check water cooling flow (ESC should remain cool), and confirm all connections are sealed before increasing to full power.

❓ FAQ

Q1: What is the difference between the Sea Lion 120A and the Sea Lion 200A?
The Sea Lion 120A delivers 120A continuous / 240A burst and is suited for builds using the 65111 motor (2KW) at 10S–12S. The Sea Lion 200A delivers 200A continuous and is designed for higher-power builds using the 65162 motor (6KW) at 12S–16S. Choose 120A for lighter, lower-power builds; choose 200A for maximum performance with the 65162 motor.

Q2: Does the Sea Lion 120A have a BEC? How do I power my receiver?
No — the Sea Lion 120A has no BEC output. You must power your receiver or remote receiver separately using a standalone BEC (5V regulated) or a small receiver battery. Connect the BEC output to the receiver's power input, and connect the ESC signal wire (JR male) to the receiver's throttle channel. Do not attempt to draw receiver power from the ESC's signal wire.

Q3: How does the water cooling work, and is it required?
The Sea Lion 120A uses active water cooling via a 4.6mm cooling pipe. Water is drawn from your board's water intake, circulated through the ESC's internal cooling channel, and expelled. This is required for sustained high-current operation — without water cooling, the ESC will overheat at 120A loads. Brief low-power testing without cooling is acceptable, but always ensure water flow before full-power riding.

Q4: Can I use the Sea Lion 120A with a VESC-based remote like the VX3?
The Sea Lion 120A uses standard PPM signal input — it is not a VESC-based ESC and does not support UART communication. The VX3 remote supports PPM mode, making it compatible with the Sea Lion 120A in PPM mode. However, UART telemetry features (motor power, temperature display on VX3 screen) will not be available — only basic throttle control. For full UART telemetry, use a VESC-based ESC such as the Manatee 100.

Q5: How do I program the Sea Lion 120A without a PC?
Use the LCD Programming Card (available as a separate variant on this page for $34). Connect the programming card to the ESC's signal wire, power on the ESC, and navigate the card's menu to set throttle range, drive direction, low voltage cutoff, brake strength, and other parameters. This is the easiest method for field programming without a laptop. Alternatively, use the USB adapter with PC software for more advanced configuration and firmware updates.