The HEXEH electric bike controller and QS273 5000W motor conversion kit represents a significant step forward in high-performance electric motorcycle and e-bike conversions. Designed for enthusiasts seeking robust power delivery and refined control, this system combines a 17-inch hub motor with the advanced Far Driver ND72680 controller, offering a compelling solution for those prioritising torque, efficiency, and adaptability in their electric two-wheeled builds.
Technical Specifications and Core Features
At the heart of this conversion kit lies the QS273 5000W motor, a 17-inch radial flux hub motor engineered for demanding applications. With a nominal power rating of 5000W and peak output capabilities significantly higher, this motor is suited to both urban commuting and more aggressive off-road use. The 273mm stator diameter provides substantial surface area for heat dissipation, aligning with HEXEH’s emphasis on thermal management to extend range and component longevity.
Paired with this motor is the Far Driver ND72680 controller, a sine-wave unit operating at 72V nominal voltage with a 680A phase current capacity. This controller employs field-oriented control (FOC) algorithms, enabling precise torque management and smooth power delivery across the rev range. The integration of regenerative braking functionality adds value for riders seeking to maximise energy recuperation during deceleration.
Key technical parameters include:
- Motor Type: Radial flux hub motor with 0.35mm silicon steel laminations
- Continuous Power: 5000W @ 72V
- Peak Torque: 280Nm (calculated from phase current parameters)
- Controller Topology: 24 MOSFET design with aluminium nitride substrate
- Protection Rating: IP65 for motor, IP67 for controller
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Communication Protocol: CAN bus with Bluetooth module compatibility
Performance Characteristics
The system’s torque delivery profile merits particular attention. Users report immediate throttle response with minimal cogging torque at low speeds, a characteristic attributed to the controller’s current vector control implementation. This proves particularly advantageous in stop-start urban environments where smooth acceleration from standstill is critical. The motor’s 55Hz maximum frequency rating suggests suitability for applications requiring speeds up to 120km/h, though actual performance would depend on final drive ratios and battery configuration.
Thermal performance has been noted as a strong point, with the motor’s 150mm width providing ample surface area for convective cooling. Riders undertaking sustained hill climbs at 15-20% gradients report consistent power delivery without thermal derating, though ambient temperature and airflow conditions naturally affect this capability. The controller’s die-cast aluminium housing with internal thermal interface material appears effective, with no reported instances of thermal shutdown during typical use cases.
Integration and Compatibility
The 17-inch wheel configuration presents both opportunities and considerations for builders. While compatible with many motorcycle frames, bicycle applications may require careful assessment of fork clearance and dropout dimensions. The 40mm axle diameter and 150mm dropout spacing suggest this system targets heavier-duty applications rather than standard bicycle frames.
Controller programmability stands out as a significant advantage. Through the Far Driver mobile application, users can adjust parameters including:
- Battery current limits (10-680A resolution)
- Field weakening intensity (0-30% adjustment)
- Regen braking curves (linear/exponential profiles)
- Temperature derating thresholds
This level of customisation enables fine-tuning for specific use cases, from cargo hauling requiring conservative power delivery to performance applications demanding aggressive torque output.
User Experiences and Practical Applications
Feedback from installers highlights the system’s versatility in different vehicle configurations. One user successfully adapted the kit to a vintage motorcycle frame, noting the controller’s compact dimensions (220×110×65mm) facilitated installation in tight engine compartments. Another builder appreciated the motor’s dual Hall effect sensor configuration, which provided redundancy critical for reliability in extended touring scenarios.
In terms of ride quality, several users commend the absence of torque ripple typically associated with lower-end hub motors. The sinusoidal commutation implemented by the ND72680 controller reportedly delivers vibration-free operation even at partial throttle openings, enhancing comfort during prolonged rides. Regenerative braking effectiveness appears variable depending on battery state-of-charge, with users recommending customisation of regen curves through the app for optimal energy recovery.
The system’s noise profile deserves mention. Unlike some high-power hub motors that produce noticeable whine under load, the QS273 maintains acoustic discretion, with only minimal harmonic resonance detectable at peak power outputs. This characteristic makes the kit suitable for stealth-oriented builds where mechanical noise reduction is prioritised.
Safety and Protection Features
HEXEH’s implementation of multiple protection circuits addresses common concerns in high-power electric vehicle systems:
- Phase Short Protection: Automatic MOSFET shutdown upon detecting abnormal current flow
- Hall Sensor Fault Detection: Controller defaults to sensorless operation if Hall signals are lost
- Dynamic Voltage Matching: Prevents overvoltage conditions during regenerative events
- Temperature-Compensated Current Limiting: Gradually reduces output as component temps approach critical thresholds
These features provide multiple layers of system preservation without requiring manual intervention, particularly valuable in demanding operating environments.
Comparative Analysis
When benchmarked against similar offerings in the 5000W class, the HEXEH system differentiates itself through controller sophistication. The ND72680’s 32-bit DSP processor and 16kHz PWM frequency exceed the capabilities of many competing units still employing 8-bit MCUs and 8kHz switching frequencies. This translates to smoother partial load operation and more precise torque control, particularly noticeable in low-speed manoeuvres.
The motor’s 12N16P (12 stator slots, 16 rotor poles) configuration strikes a balance between torque density and high-speed capability. While some competitors opt for higher pole counts to maximise low-end torque, this design philosophy ensures competent performance across a broader RPM range without excessive iron losses.
Maintenance and Longevity Considerations
Durability features include the motor’s double-sealed labyrinth bearing configuration and controller conformal coating. Users operating in coastal environments report no degradation after 12 months of exposure to salt-laden air, though regular maintenance of axle interfaces remains advisable. The stainless steel spoke eyelets in the motor hub have drawn praise for resisting corrosion where cheaper galvanised components might fail.
Brushless design eliminates wear items associated with commutator systems, though periodic bearing inspections (recommended every 5,000km) help maintain optimal mechanical efficiency. The lack of user-serviceable parts within the motor itself aligns with industry trends towards sealed unit construction.
Environmental Considerations
The system’s efficiency profile contributes to its environmental credentials. Laboratory testing suggests peak efficiencies of 93% at the motor-controller interface when operating in the 20-80% load range. While final system efficiency depends on ancillary components like battery management systems and charging infrastructure, the core drivetrain’s performance compares favourably with industrial electric motor standards.
Conclusion
HEXEH’s QS273 motor and ND72680 controller combination establishes itself as a serious contender for high-performance electric vehicle conversions. Its technical sophistication balances raw power delivery with nuanced control capabilities, while robust construction addresses the demands of intensive use cases. The system particularly shines in applications requiring adaptable performance characteristics, from urban commuters prioritising range to off-road builds demanding instant torque.
While the 17-inch wheel format and substantial mass (15kg for motor alone) may limit compatibility with smaller bicycle frames, these characteristics prove advantageous in motorcycle-oriented applications where stability and power density are paramount. As electric conversion technology continues evolving, this kit demonstrates how advanced motor control algorithms can elevate both performance and refinement in aftermarket EV systems.
ASIN: B0DJSXDN59
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