Grin: Baserunner V4 Series


The new Baserunner V4 Series from Grin Technologies is a fully integrated, waterproof Controller for use with a variety of Hub Motor combinations, with/without the Cycle Analyst, handling up to 60V Max and 80A Peak Phase Currents (45-50A Continuous). This ensures compatibility with most eBike systems available today and programmable options for flexibility in future.

All of the new V4 models include the WP8 CA Plug, with either Hailong, Reention, Tube, Fork or Plate Mounts to match your bike’s arrangement and a 38cm cable length via Z910 HiGo 9 pin plugs or L1019 10 pin. Extension cables from Controller to Motor are available in 60cm and 90cm versions, so you can choose the best mounting point for any build.

Baserunner V4 with Z9 Connector (left) or L10 Connector (right)

The Baserunner V4 was designed to be run ‘Headless’, so a Throttle/PAS/Torque Sensor can be plugged-in via the integrated 6 pin HiGo Connector for a lightweight set-up (see the Manual for how to do it correctly). Additional features are available by adding a Cycle Analyst, including Proportional Regen if your Motor supports it. Software updates will continue to provide further refinements.

All Programming is handled via the Phaserunner Suite which also requires a computer for set-up to mate and configure, with a USB->TTL connector (sold separately and linked below). Core features are shared across Grin’s Controllers, so there is parity between Baserunner and Phaserunner.

Baserunner V4 Series Specifications:

• Dimensions (L x W x H, mm): 98 x 55 x 15mm
• Battery Range: 19-60V
• Waterproofing: Fully Potted Circuitry, IP rated signal plugs
• Phase Current Rollback Temp: 90°C Internal Temp (casing ~70°C)
• Matt finish
• Embedded communications jacks
• All versions require soldering to Power Source

Baserunner V4 L10 Specifications:

• Programmable up to 80A
• Weight: 0.26kg

Baserunner V4 Z9 Specifications:

• Programmable up to 55A
• Weight: 0.20kg

Baserunner V4 Series Features:

• Slim Profile fits in popular battery cradles, or fits discretely with other mount options
• New in V4 Model, all Waterproof plugs for CA3, PAS Sensor, and OEM Cables
• Ability to decode Combined Speed / Temperature signals in motor cable
• Proportional Regen available through throttle signal or stand alone wire
• Works both Sensored and Sensorless, and even with very high eRPMs
• Waterproof, 100% potted electronics
• Fully Programmable parameters (regen voltage, max phase and battery currents etc.)
• Field Weakening allows you to run motors faster than normal back-emf limit
• Embedded LED with comprehensive flash codes for troubleshooting
• Virtual Electronic Freewheeling for removing drag of regen capable hub motors
• Broad Operating Voltage range from 20V to 60V (14S Li-Ion, 24s LiFe)
• Automatic Thermal Rollback prevents mosfet damage from controller overheating

Identifying the correct Connectors and Mounts for your Baserunner V4:

With so many parts to consider within your build, it’s best to have a shortlist of what you are looking to combine: the photographs below show all of the options available today.

Compatible Hub Motor Cables are: Z9 (left) and L10 (right). AKA: Z910 HiGo 9 pin and L1019 10 pin

The Baserunner can be fitted inside your Battery’s Housing. The Hailong Battery Mounts fit: HL-03/HL-01 (left). The Reention Battery Mounts fit: DP-9C/DP-6C (right)

Here is a Baserunner installed under a Hailong Enclosure with L10 Connector

The Baserunner can also be installed externally for improved airflow with Tube, Fork and Plate Mounts (left to right), suiting eMTB, Brompton, Cargo and more.

Baserunner Version History:

V3 Device: The V3 update took place in 2020 and had the exact same connector standard as the V2 model, but featured an internal demux circuit to support combined temperature and speed signals in the Z910 motor plug. This demux circuit is backwards compatible and fully supports motors that use the white wire as just a speed sensor or just a temperature sensor.

V4 Devices: In late 2021 Grin released the V4 Baserunners with a substantial overhaul. The V4 units continue with the 8 pin CA-WP plug and also have a 9 pin Main signal plug to provide optional support for conventional ebike displays. The independent 3 pin JST throttle plug has been removed and replaced with a 6 pin HiGo connector that can be used for direct hookup of a throttle, a PAS sensor, or a Torque sensor, even without a CA3 device in the system.


V4 Baserunner User Manual

Phaserunner Software Suite from Grin Tech, Mac
Phaserunner Software Suite from Grin Tech, Linux
Phaserunner Software Suite from Grin Tech, Windows
Windows drivers for the FTDI chipset inside the USB-TTL adapter can be found through FTDI here

Connectors are sold separately! Click here to see what is available.



  • Card Payment
  • Klarna
  • PayPal Credit
  • PayPal Payment

Providers & Grants:

Halfords Cycle2Work Premium
GCI Employee
Bike2Work Scheme
Caboodle Cycle2Work Premium