Frankenrunner (New!)

Page Last Modified On: May 6, 2022


Frankenunner ModelsThe Frankenunner is a field-oriented controller that Grin has introduced in 2022 as a stop-gap substitute for the popular Phaserunner device. It is based around a stock ASI BAC855 with all of our Phaserunner modifications tacked onto the end rather than embedded in a custom enclosure. While not quite as slick and compact, it still delivers the same punch, and boasts all the updated features that will be present in the V4 Phaserunner devices too. That includes all waterproof signal connectors, a 9 pin OEM main cable to support the use of certain 3rd party displays, support for motor temperature sensoers, and direct attachment of PAS or Torque sensors.

This controller was designed as a universal device that can fit on almost any bicycle frame and handle almost any motor system in the 500-2000 watt power range. 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 Frankenrunner_L10 has a cable exit for compatibility with all the motors supplied by Grin with the L1019 connector, while the Frankenunner_MT is connectorized for separate cable harnesses between the controller and motor. 



  • Wide Operating voltage range from 20V to 86V (20S Li-Ion, 24s LiFe)
  • Remote on/off switch compatible
  • Compatible with CA3-WP display and control device
  • 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
  • Virtual Electronics Freewheeling allows you to experience zero drag with direct drive motors
  • Higher motor efficiency than typical trapezoidal controllers
  • Torque based throttle command (no twitchy throttle with powerful system)
  • Automatic thermal rollback to prevent controller overheating

Cables and Connectors

Both models of the Frankenrunner use the same connectors for the Battery, Cycle Analyst, Throttle, and Communication plugs, but they differe in how they hook up to the motor. 


XT60 Battery Connector Battery - XT60: The hookup for the battery pack is with an embedded XT60 style male bullet connector. Each Phaserunner includes an 80cm battery cable terminated with an XT60 female plug at one end and Anderson Powerpoles on the other for hookup to your battery pack. We recommend not using the XT60 plug for making a live connection to the battery as the inrush current spark to the controller capacitors can damage the gold plated bullet plugs.  
  CA3 Display - WP8: The Frankerunner uses the waterproof WP8 Cycle Analyst plug standard which includes motor temperature and on/off power lines to the CA3. Please use the WP8->JST adapter for use with older models of Cycle Analyst using the 6-pin JST-SM plug. 
  Mains Connector: A 9 pin plug provides all the signals needed for conventional ebike wiring harness strategies where the throttle and ebrake connect to the motor controller and a 3rd party display has the on/off power and communicates the assist level.  For the controller to turn on, the key input on either the Mains or CA plugs must be shorted to V+. 
  PAS Connector: A 6 pin HiGo plug provides an input for the direct hookup of either PAS or Torque sensors to the motor controller. This is required for pedalec ebikes that don't use a Cycle Analyst. With a Cycle Analyst system this plug is not used as the PAS sensors, throttles, and all accessories plug into the CA3 instead.   
  Communications - TRRS:  The Phaserunner V3 uses a TRRS jack to support communication to computers and smart phones using our USB->TTL adapter cable. As shipped there is a rubber plug to seal this jack from water. Unlike the V2 and earlier Phaserunners which had a similar looking TRS jack, the TRRS in the Phaseurnner V3 also has 5V present to support the future release of powered serial to bluetooth adapters.


L10 Particulars

The only additional wire on the Frankenrunner_L10 is the motor cable, which is 40cm long and terminated with the female L1019 plug for a rugged connection to Grin motors that use this connector standard 

L1019 Connector Pinout Motor - L1019: The motor connection on the Phaserunner_L10  is through the locking and waterproof Higo L1019 plug or the Cusmade equivalent. The cable uses 3mm^2 (12 awg) wire for the 3 motor phase leads to support high amperage, and has a total of 7 smaller gauge signal connectors. Five of these are used for the hall signals and power, while the extra two serve for the motor temperature sensor (grey) and a wheel speed sensor (white).   

MT Particulars

On the Frankenrunner_MT, the hookup between the motor and the controller is done via 3 separate plugs rather than through a single cable with an overmolded connector. 


MT60 Plug for Motor Phase Wires on Phaserunner_MT Model  Motor Phase - MT60:  The 3 motor phases are terminated with a male MT60 bullet connector. This compact plug supports high phase amperages in a very small connector size. 
 Motor Hall Signals use 5 Pin JST-SM Motor Hall - JST-SM: The hall plug is a 5 pin female JST connector using the same pinout standard we adopted since 2008. 
 Motor Speed and Thermistor Pass-Thru Cable to CA3-WP Plug Speed/Thermistor Pass Thru - JST-SM:  The extra 2 pin female JST-SM plug is present in order to hook up additional motor signals. If the motor has a built in temperature sensor, this signal can be fed to JST Pin1 to show motor temp on the CA3 and enable thermal rollback. Geared motors that have an internal speed sensor should use Pin2 as a pass-thru of the speedometer signal line to get speed display on the CA3.  If a direct drive motor is used with no speed sensor, the setting at address 174 "HDQ Replicating Hall" should be checked for a speed reading to appear.  


With the Frankenrunner_MT, we provide the following optional motor cable harnesses for different motor applications. The Anderson terminated cable is compatible with our hub motors sold from 2019 and earlier and is recommended for 3rd party motors for which there isn't another compatible plug type

Phaserunner Stock Battery Cable Harness Battery Cable: Both Phaserunner models come stock with a 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 + 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 extended periods.
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 L10 Motor Harness L1019 Motor Harness: This cable harness can be used to connect the Phaserunner_MT controller to hub motors that use the L1019 plug standard. In general we recommend the Phaserunner_L10 model in this application, but we made this for customers who already have a Phaserunner_MT and now want to use it on a new motor with the L1019 connector.
Phaserunner to BBSHD Mid Motor Harness BBSHD Motor Harness: -ON PAUSE- The original BBSDH harness we had made up for the Phaserunner units is not as plug and play compatible with the Frankenrunner and the CA3-WP devices. We will be revisiting and revising this product and should have an updated cable harness assembly available in May. 

User Manual



CAD Files



Software Suite

Phaserunner Suite, Windows, Portable

Phaserunner Suite, Windows, Installer

Phaserunner Suite, macOS (Requires macOS 10.13 or newer)

Phaserunner Suite, Linux

There is also a version for Android that is in development, and available for beta testers on the Google Play Store. This requires the use of a USB OTG compatible device, as well as a USB OTG adapter to connect our USB->TTL programming cable to the micro USB or USB-C connector present on most smartphones.  

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




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. 

Controller Not Turning On:The most common reason for this is that the on/off switch wiring is not wired up to turn the device on. As mentioned in the V3 Phaserunner Updates document, by default now the on/off switch wires of the controller are not shorted together. In order for the Phaserunner to turn on when battery power is applied, either a CA3-WP device needs to be plugged in and the MFSwitch turned on, the on/off wires under the throttle heatshrink are hooked together, or the WP8->JST adapter is plugged in which shorts together the V+ and Key pins of the WP8 plug.

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 (noisy power supply instead of battery powering controller) 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 updating to the latest V1.3 release as that has fixed a number of potential communication problems. 

Instantaneous Phase Overcurrent Fault (2-2 Flash): 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. In some cases where this tuning along is not sufficient, then the currently regulator Ki and Kp terms can be adjusted inndependantly.  

POST Static Gate Fault (1-8 Flash): 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 is water ingress inside the motor causing paths for electrical connectivity with the phase wires. 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. 

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 degrees 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

Frankerunner controllers are available individually from our store page (both the L10 and MT models) or as part of the High Voltage and DIY conversion kit bundles. We are manufacturing the devices daily and there is currently a ~1-2 week order backlog before a unit purchased now will be complete and ready to ship.