Fat Tad Electric Conversion System – 48V 15Ah Battery

• Designed specifically for the Sun Fat-Tad CXS
• Complete SINET™ rear-wheel electric conversion system with 48V 15Ah battery included
• 750W nominal rear hub motor
• 20" x 4" fat-tire rear wheel configuration
• Choose Cadence Sensor or Bottom Bracket Torque Sensor
• 3.5" full-color SINET™ LCD with USB charging port, diagnostics, and programming
• Topeak handlebar extender included for LCD mounting
• Fat-Tad-specific battery mounting hardware included

A purpose-built electric conversion system engineered specifically for the Sun Fat-Tad CXS, combining strong rear-wheel drive, smooth SINET™ motor control, and model-specific mounting hardware for a clean, integrated installation.

Fat Tad Electric Conversion System – 48V 15Ah Battery

The current-generation E-BikeKit™ Fat-Tad Conversion System uses the latest SINET™ platform with a 750W nominal rear hub motor, integrated sine-wave controller, full-color LCD, throttle-on-demand, locking e-brake levers, and your choice of cadence or torque-sensing pedal assist.

The motor is built into a USA hand-built 20" x 4" fat-tire rear wheel configured for the Fat-Tad CXS and its wide rear dropout spacing. Rear-wheel drive provides strong traction and dependable assist for pavement, gravel, and mixed-terrain use.

The included 48V 15Ah lithium-ion battery slides into the SINET™ battery/controller cradle. Fat-Tad-specific mounting hardware positions the battery securely on the trike while maintaining balanced handling and a finished installation.

A Topeak handlebar extender is included to provide a practical mounting location for the SINET™ LCD on the Fat-Tad cockpit.

Who is this system for? Fat-Tad riders who want strong electric assist, confident fat-tire handling, and a complete model-specific system for recreation and mixed-terrain riding. The total system load limit is 300 lbs.

• USA hand-built 20" x 4" Fat-Tad rear motor wheel
• 750W nominal rear hub motor
• 48V 15Ah lithium-ion battery
• Integrated SINET™ sine-wave controller housed in the battery cradle
• SINET™ battery/controller cradle
• 3A smart charger
• SINET™ 3.5" full-color LCD with USB charging port
• Topeak handlebar extender for LCD mounting
• SINET™ component wiring harness
• Thumb throttle
• Left and right locking e-brake levers with motor cutoff
• Short motor cable optimized for tadpole-trike routing
• Fat-Tad-specific battery mounting hardware
• Torque arm(s), washers, zip ties, and required conversion-system hardware

Your pedal-assist selection determines the sensor included:

• Cadence Sensor: External cadence sensor and magnet disc for straightforward pedal-assist operation
• Bottom Bracket Torque Sensor: SINET™ 68 mm square-taper torque-sensing bottom bracket with required SINET™ extension cable

Cadence Sensor

The cadence sensor detects crank rotation and activates pedal assistance according to the assist level selected on the LCD. It is the simpler installation option for most conversions.

• External cadence-sensing system
• Detects crank rotation
• Does not measure rider force
• Simpler installation

Bottom Bracket Torque Sensor

The optional SINET™ bottom bracket torque sensor measures rider effort and provides motor assistance in proportion to how hard you pedal, creating a smoother and more natural riding feel.

• 68 mm square-taper bottom bracket
• Required SINET™ extension cable included
• Measures rider pedaling force
• Provides smooth, proportional assistance
• Requires compatible 68 mm square-taper bottom bracket fitment
• Installation requires a protected 3/8-inch cable-routing hole through the bottom bracket shell

Which should you choose? Cadence sensing is simpler to install and provides dependable traditional pedal assist. Torque sensing provides a more natural, proportional response but requires compatible bottom-bracket fitment and a more involved installation.

The SINET™ Bottom Bracket Torque Sensor provides smooth, proportional pedal assist by measuring how much force you apply to the pedals. It provides a more natural riding feel than traditional cadence-only pedal assist, but installation is more involved.

Before selecting the torque sensor, please understand the installation requirements:

• Your bicycle or tricycle must have a compatible 68 mm bottom bracket shell
• The torque sensor is designed for use with square-taper cranks
• Both crank arms and the existing bottom bracket must be removed
• A 3/8-inch cable-routing hole must be drilled through the bottom bracket shell
• The torque-sensor cable is routed through the 3/8-inch opening
• The supplied rubber grommet seats in the opening to protect the cable and provide a clean finished installation
• Proper crank and bottom-bracket removal tools are required

Can I install the torque sensor myself?
Yes. If you are comfortable removing crank arms and a bicycle bottom bracket, installing a replacement bottom bracket, drilling the required 3/8-inch cable-routing hole, and completing the rest of the conversion, this installation can be performed by an experienced DIY installer.

We recommend reviewing the installation requirements and watching the installation video below before choosing the torque-sensor option so you can decide whether this is a job you are comfortable performing yourself.

Torque Sensor Installation Video

Watch the complete installation process for the SINET™ 68 mm square-taper bottom bracket torque sensor, including crank and bottom-bracket removal, drilling the 3/8-inch cable-routing hole, routing the sensor cable, installing the torque sensor, and seating the protective grommet.

Watch the SINET™ Torque Sensor Installation Video on YouTube →

Important: This video demonstrates installation on a compatible 68 mm square-taper bottom bracket. Some traditional upright tricycles use a one-piece crank and require additional crank-conversion components before the SINET™ torque sensor can be installed.

Prefer a simpler DIY installation?
Choose the Cadence Sensor. It provides dependable pedal assist without replacing the bottom bracket or drilling a cable-routing hole.

Want a Shop to Handle the Installation?

If you would rather have the conversion professionally installed, start with the E-BikeKit Dealer Locator. Enter your ZIP code to find participating dealers near you, then contact the shop directly to confirm installation availability.

Find an E-BikeKit Dealer Near You →

No E-BikeKit dealer nearby? Contact a local bicycle shop and ask whether they are willing to install an electric bike conversion system. Give the shop our contact information and have them call us directly. We can quickly help them get set up as an E-BikeKit dealer, review the system with them, and provide technical support for your conversion.

If you find a local shop that is interested but would prefer that we contact them, contact E-BikeKit and provide the shop's information. We can reach out and help get the process started.

Questions before ordering? Call E-BikeKit at 1-866-882-3245, Monday–Friday, 9am–5pm EST, or email support@ebikekit.com.

• Quiet, efficient sine-wave motor control
• Integrated controller housed in the battery cradle
• 3.5" full-color LCD with USB charging port
• Matched waterproof electrical connectors
• Cadence and torque-sensing pedal-assist compatibility
• Throttle-on-demand
• Motor cutoff through both locking e-brake levers
• Cleaner installation with fewer external components

The included SINET™ 3.5" full-color LCD provides ride information, system setup, diagnostics, and programming controls. A Topeak handlebar extender is included with the Fat-Tad system to provide a practical display mounting location.

• 3.5" full-color display
• USB charging port
• Battery voltage and level display
• Current speed
• Trip meter and odometer
• Pedal-assist level selection
• Walk-assist mode
• Error diagnostics
• Advanced programming menu

Watch the video below for an overview of the SINET™ LCD, including initial setup, programming, display operation, and commonly used system settings.

Watch the SINET™ LCD Programming Guide on YouTube

Download the SINET™ LCD Quick-Start Guide (PDF)

• Application: Sun Fat-Tad CXS
• System Type: Model-specific rear-wheel electric conversion system
• Nominal Motor Power: 750W
• System Voltage: 48V
• Motor Type: Brushless rear hub motor
• Rear Wheel: 20" x 4" fat-tire configuration
• Rear Dropout Spacing: 170–190 mm
• Controller: Integrated SINET™ sine-wave controller housed in battery cradle
• Battery: 48V 15Ah lithium-ion battery included
• Charger: 3A smart charger included
• Display: SINET™ 3.5" full-color LCD with USB charging port
• Display Mount: Topeak handlebar extender included
• Throttle: Thumb throttle included
• Pedal Assist: Cadence Sensor or 68 mm Bottom Bracket Torque Sensor
• Total Load Limit: 300 lbs
• Wheel Build: USA hand-built
• Spokes: Heavy-duty stainless steel

This system includes the current E-BikeKit 48V 15Ah lithium-ion battery, integrated SINET™ controller cradle, matching 3A charger, and the Fat-Tad-specific battery mounting hardware shown in the product photos.

• Nominal Voltage: 48V
• Capacity: 15Ah
• Energy: Approximately 720Wh
• Cell Configuration: 21700 cells, 13S3P
• Maximum Continuous Discharge: 30A
• BMS Protection Current: 30A
• Maximum Charge Voltage: 54.6V
• BMS Low-Voltage Protection: 36V
• Battery-to-Cradle Interface: Four-blade contact system
• Controller: Integrated into battery cradle
• Estimated Range: Approximately 20–40 miles depending on rider weight, terrain, speed, pedal input, assist level, temperature, and total load
• Charger: 3A smart charger included
• Charge Time: Approximately 5 hours
• Expected Life: Approximately 400–500 charge cycles

The supplied mounting hardware is configured for the Fat-Tad frame and allows the SINET™ battery/controller cradle to be mounted securely while maintaining balanced handling and a clean installation.

No additional universal battery mounting hardware is required when using the supplied Fat-Tad mounting system as intended.

View the 48V 15Ah Battery Dimensional Drawing (PDF)

This conversion system is configured specifically for the Sun Fat-Tad CXS. The supplied rear motor wheel, display-mounting solution, battery mounting hardware, and conversion components are selected around the Fat-Tad platform.

Before ordering, confirm:

• You have the compatible Sun Fat-Tad CXS configuration
• The rear dropouts and frame are in safe operating condition
• The rear dropout spacing is compatible with the supplied Fat-Tad motor wheel
• The intended battery mounting location is available for the supplied mounting hardware
• You have a compatible 68 mm square-taper bottom bracket if selecting the torque sensor

If you are unsure whether your Fat-Tad configuration is compatible, contact E-BikeKit before ordering.

This is a model-specific conversion system, but installation still requires mechanical bicycle work and proper electrical-component mounting and routing.

• Install the Fat-Tad-specific rear motor wheel
• Install and properly secure the supplied axle hardware and torque arm(s) as required
• Install the Fat-Tad-specific battery mounting hardware
• Secure the SINET™ battery/controller cradle to the mounting system
• Install the 48V 15Ah battery into the cradle
• Install the Topeak handlebar extender and SINET™ LCD
• Install the thumb throttle and locking e-brake levers
• Install the selected pedal-assist sensor
• Route all wiring away from steering components, tires, chain, and other moving parts
• Verify brake cutoffs, throttle operation, pedal assist, wheel clearance, steering movement, and display settings before riding

Professional bicycle-shop installation is recommended if you are not experienced with cranksets, bottom brackets, rear wheels, battery mounting, and electric conversion systems.

Learn more: Top 25 Frequently Asked Questions

Questions? Call us toll-free at 1-866-882-3245, Monday–Friday, 9am–5pm EST, or email support@ebikekit.com.

Battery shipping: Lithium-ion batteries ship separately via FedEx Hazmat and may require a delivery signature. It is normal for the conversion system, battery, charger, or mounting hardware to arrive in multiple shipments or on different days.