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The Phaserunner is a compact state-of-the-art field oriented motor controller (FOC) from Grin Technologies based around the sophisticated control electronics from Accelerated Systems Inc. of Toronto. It is ideally suited for running brushless motors for electric vehicles in the 500-2000 watt power range, and once you have experienced the smooth response of a FOC with a torque throttle it's hard to go back to a the setup you had before.

This controller was designed as a universal device that can fit on almost any bicycle frame and handle almost any motor system. You can power it from a 24V battery or a 72V battery, and run your phase current to peaks of over 90 amps, though the continuous current capability without additional heatsinking is typically 45-50A. The wiring is pared down to the bare basics for a nice clutter-free installation; including a throttle plug, a Cycle Analyst plug, cable to your motor, and a cable to your battery pack.



  • Remote on/off switch compatible
  • Direct plug for both V2 and V3 Cycle Analysts
  • 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
  • Higher motor efficiency at low speeds / high torques
  • Torque based throttle command (no twitchy throttle with powerful system)
  • Operating voltage range from 20V to 90V (21S Li-Ion, 24s LiFe)
  • Automatic thermal rollback to prevent controller overheating

User Manual

Download Latest V2 Phaserunner User Manual with XT60-MT60 Plugs

V1.0 Phaserunner User Manual (Units produced Nov 2016 - Aug 2017) has internal on/off button, long battery and phase wires..

Phaserunner Dimensional Diagram


Software Suite

Phaserunner Software Suite from Grin Tech, Windows
Phaserunner Software Suite from Grin Tech, Linux
Phaserunner Software Suite from Grin Tech, MacOS (Requires Mac OS 10.12 or newer)


The drivers for the FTDI chipset inside the USB-TTL adapter can be found through FTDI here -

Cables and Connectors

V2 Phaserunner ConnectorsThe V2 Phaserunner is connectorized on the device itself with MT60 / XT60 plugs for the motor phase and battery leads, and JST-SM for the hall, Cycle Analyst, and throttle connectors. These are user installable connectors, but we offer pre-made cable harnesses for mating to common motor and battery standards. 

The original V1 Phaserunner (2016-2017) had the battery and motor leads emerge directly from the potting and so did not support interchangeable harnesses. 

Phaserunner Stock Battery Cable Harness Battery Cable: The Phaserunner comes stock with an 84cm long XT60 to Anderson battery cable for mating with batteries that use Anderson Powerpoles. 
Stock Anderson Motor Harness Stock Motor Harness: The standard motor cable has staggered MT60 and male JST-SM connectors on the controller end and Anderson + female JST-SM connectors for the motor. This is compatible with all of the medium to high power hub motors that Grin has sold since about 2009, and is available in both a short (45cm) and long (120cm) cable length option. Note that the Phaserunner is capable of delivering high enough continuous phase current to melt the anderson plugs, and we don't recommend using this connector in applications that will be sustaining more than 70 amps of phase current for long times.
Phaserunner Z910 HiGo Motor Cable Harness HiGo Z910 Motor Harness: This cable harness terminates at the motor end with the 9 pin waterproof HiGo motor plug popular in many lower power hub motors. We recommend limiting the phase current to no more than 50 amps with this connector harness and plug standard. Notice that if the motor has a speedometer sensor built in, that signal will not be connected to the Phaserunner's CA Plug and you will need to use a CA with an external speedo.;
Phaserunner to BBSHD Mid Motor Harness BBSHD Motor Harness: This cable harness supports upgrading the stock internal controller in a BBSHD mid-drive system with an external Phaserunner for improved handling and higher power levels. It has motor and hall terminals that mate with the plugs present in the central motor, and has a secondary cable harness to bring the PAS sensor and motor temperature signals up to the V3 Cycle Analyst on the handlebar. 


A Video by Grin Technologies

A Video by Grin Technologies


Most people are able to setup and tune the Phaserunner with relative ease using our software suite and following the direction in the user manual. Here are some of the more common troubleshooting issues that we have run into doing tech support. 

Motor Not Detected During Autotune:  The most common reason for this error is not that the motor is disconnected (though that will do it), but rather communication errors or delays between the software suite and the Phaserunner device. It will happen consistently if there are two instances of the Phaserunner suite open on the computer at the same time, and can also occur if there is significant electrical noise interference on the communications cable, or if the computer is running the wrong virtual COM port driver. MAC computers are especially prone to this latter problem. If you are experiencing these issues with the V1.0x software we recommend trying out the V1.1 beta software release to if that corrects the problems.

Instantaneous Phase Overcurrent Fault: This is a fault that typically occurs when there is a sudden change in the motor eRPM (such as hitting a pothole, or the motor transitioning from open loop to closed loop sensorless operation), and it usually means that the current regulator bandwidth and/or the PLL bandwidth are not high enough to track the dynamic motor response. Increasing both the PLL and Current Regulator in tandem will usually result in setting that doesn't result in phase overcurrent faults. 

POST Static Gate Fault: This fault occurs if there is some stray electrical conductivity detected between one of the phase wires and either the V+ or Gnd bus. It will occur if there is a blown mosfet, if the motor wire is nicked at the axle and is shorting a phase lead to the motor casing, or if for some reason there is some unexpected conductivity on one of the phases. If this message shows up, disconnect the Phaserunner from the motor, apply the throttle, and look at each of the phase open circuit voltages from the edit parameter menu. They should be around 0.5 Vnom. If you see a value of 0.00 or 1.00 Vnom, then it usually means there is a damaged mosfet. If there is a value more like 0.2 or 0.8 Vnom, then you can increase the open circuit test window from the default of 0.25 up to about 0.4 and then it will operate fine again. 

Damaged XT60 Connector: We've seen several instances with high power rigs where the XT60 plug for the battery cable has become badly damaged from arcing, sometimes even melting the contacts. The battery current draw on the Phaserunner is much lower than what the XT60 contacts are rated for, so we believe that this failure is mostly the result of mechanical stresses on the battery leads pulling the connector at an angle and causing interruptions and arcs in the power flow. It's possible to spread apart the 4 tongs of the male pin for a tighter mechanical contact, and we recommend ensuring that the battery cable is not being tugged (eg by cable ties) in such a way that it pulls the connector at an angle. Instead the battery connector/cable should float freely so that it stays aligned and in good contact. 

Default Parameter File

If you have messed around with deep settings in the Phaserunner or managed to corrupt the device from interrupted communications, we have this file available here that allows you to restore all the parameters to their default state. If your browser displays the file inline instead of downloading it, right click the link and select "Save Link As..." 

Download Defaults Parameter File

You will need to enable Level 3 Access from the advanced tab prior to loading and flashing with this XML file in order to change any deeper settings that may have been affected.

Level 3 Access Checkbox

Additional Details

We posted a fair amount of our test data in the endless-sphere forum during the development and initial pilot roll-out of the Phaserunner controller, and we've highlighted some of this data here:

  • Efficiency comparison: Here we did direct comparisons on our dyno of a standard Infineon trapezoidal controller versus the Phaserunner controller running the same hub motor with the same battery current. You can see upwards of a 5% improvement in motor efficiency with the Phaserunner hub, as well as a steeper drop off in torque vs RPM
  • Field Weakening: Here are some discussions of the field weakening capability of the Phaserunner and how that affects both the no-load current draw and the unloaded RPM.
  • eRPM Limit: Here we showed the Phaserunner controller running an RC outrunner motor at 72,000 eRPM's. However, ASI advised that beyond 60,000 eRPM the controller performance can suffer and we only did the testing unloaded.
  • Thermal Rollback Limits: While the Phaserunner can put out 96 amps of phase current for short periods, within several minutes the heatsink will reach over 80 ℃ and thermal rollback will kick in, automatically reducing the maximum phase amps. The maximum continuous phase current depends on installation details and air flow but is typically between 50-55A. The chart below shows the measure thermal rollback current when mounted with no additional heatsink to the downtube of a bicycle as a function of bicycle speed.
    Phaserunner Thermal Rollback Current
    The use of extra finned heatsinks thermally linked to the Phaserunner base can increase this continuous phase current to nearly 70 amps, while the current limit if placed inside an insulated cavity or bag with no airflow at all will be much lower, around 30A.

Where to Order