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A50S V2.1

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0.10 KGS
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New V2.1 now here, includes power connectors to make swapping ESCs easier and a huge 20 pin logic connector for Hall sensors, UART, CANBus, etc.


The A50S was designed specifically for use in Beatleweight and Featherweight combat robots. It runs the extremely popular VESC®*-Project firmware. We use it for drive on our FW Elevate and weapon/drive on our BW Uplift.

Our biggest problem with the BLHeli_32 ESCs that are very popular for BW weapons, is the lack of a sensible programming interface. So we have a standard microUSB connector for connection to a PC for tuning with VESC®* Tool.

Additionally by using VESC® firmware they have excellent current control so you are less likely to melt your motors!


The A50S can be used for both Brushed and Brushless motors.


Quick tips on setup

Please attach included capacitor as close to the unit as possible.

!!ONLY USE 1 BEC, do not connect the 5v wire on all but one or the BEC can be damaged!!

Please be careful when programming settings. 

We recommend detecting motors using the FOC motor setup wizard. This will automatically find the correct settings for your motor. 

LiPo batteries are extremely dangerous if handled incorrectly.

ALWAYS run with a fuse. 


Current Handling

6S (30V FETs)

22A continuous with no additional cooling

35A continuous with light airflow

50A burst 

12S (80V FETS, 65V MAX)

15A continuous with no additional cooling

25A continuous with light airflow

40A burst

Mechanical Features

  • Dimensions: 35.5 x 21 x 13.8mm without wires
  • Weight ~8g

 Electrical Connections

  • XT30 Battery input
  • MR30 Motor output
  • 20 Pin Pico-Clasp connector for IO
    Hall, Motor temp, 5v, 3.3v, SWD, External ADCs, SPI, I2C, PPM, CANBus, Power enable


Motor Commutation Modes

  • FOC - Sensorless, Hall Sensors, HFI
  • BLDC - Sensorless, Hall Sensors
  • DC - For driving brushed DC motors on outputs A and C.


Motor Control Modes

  • Current - Controls current to motor irrespective of duty cycle
  • Duty Cycle - Controls duty cycle sent to motor irrespective of current
  • PID RPM control - Controls motor RPM using a PID loop, gives high torque even at low rpm.


Control Interfaces

  • PPM
  • UART
  • CANBus (UAVCANv0)


Voltage Rating

  • 6S Model:    4-27v, 2-6S LiPo
  • 12S Model:  4-52v, 2-12S LiPo

Limited by DCDC at 65V MAX

MOSFETs are 80V.


Safety Features

  • Active current limiting - actively limits motor current to stay below programmed limit
  • Software over current protection - stops motor running if the current exceeds programmed limit
  • Slow temperature cutoff - ramps down motor current when approaching programmed max temperature
  • Battery voltage cutoff - ramps down motor current when approaching programmed voltage cutoff
  • Under / Over Voltage cutoff - stops motor running if the voltage goes outside the programmed range


Programming features - using VESC®* Tool

  • Adjustable current limits, Battery and Motor current are independently controlled
  • Adjustable voltage limits
  • Adjustable RPM limits
  • Adjustable Power limits
  • Adjustable duty cycle limits
  • Adjustable regenerative braking
  • Adjustable throttle curves and ramping time
  • Real time and Sampled Data monitoring and graphing
  • Automatic motor detection and tuning


Motors tested and tuned to work, (Config files available here

  • 1806 - 2300kv (OPBox motor)
  • TP2040 - 3Y 6050kv
  • SK3 4250
  • NTM4248 - 650kv
  • 5065


The A50S runs the popular VESC®*-Project firmware by Benjamin Vedder. 

* VESC is a registered TM, owned by Benjamin Vedder 

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  • 5
    ESC Performance

    Posted by josue on 18th Dec 2020

    These ESC are great, I use the option speed control to drive the motor. I t was necessary to put a small capacitor in order to drive my motor. I would be helpful to have only one ESC to control 2 motors, looking for simplicity and for reducing weight.

  • 5
    Brushed/Brushless configuration and performance

    Posted by Isaak A Malers on 2nd Dec 2020

    - One of the things I like the most about the A50S is its ability to drive DC motors above their voltage rating safely. In Brushed mode, with a duty cycle limit of 65% and a current limit of 1.8amps per motor, I am able to run Silver Sparks (Mabuchi 050) motors on 24 volts. Connecting them directly to a 24 volt source would destroy the motor extremely quickly. This opens up a LOT of options for beetles, that previously were difficult because you pretty much had to run 3s or 4s batteries to avoid destroying drive motors. The A50S is my favorite brushed drive solution for 3lbs, and even 12lbs robots for this reason.

    - As far as brushless performance goes, the A50s has a lot of options available for tuning that no other product can match. By setting current controls and using FOC mode, you can control how much heat gets put into a motor and ensure nothing burns up. The high voltage capacity and current limiting enables some interesting design choices. I'm able to run a "3s max, 25 amp max" motor on 6s, with a 17 amp current limit in the A50s. This solution runs cooler, pushes more power, and with a gear ratio adjustment has the same top speed. The result is a huge spin-up improvement, with a system that runs stone cold. I've also tested a Prop drive 5050 on the A50S, with a 55 amp current limit. Predictably, the system overheated. However: the A50s gracefully protected itself by providing less and less current as it got too hot. I wanted to see how big of a motor I could get good performance out of. Its possible to get 10x the rated amperage through some of the bigger vescs for very short bursts, enabling a Fesc6.6 to power a 300amp stall motor. For the A50s I was seeing 55 amp short term bursts before the A50s started to really struggle with delivering more current, and the motor performance suffered. Overall: for brushless motors the A50S is a compelling choice for beetles that want to push a lot of volts instead of a lot of current. It enables designs using a 1200w motor at 6s, which is much more manageable than a 1200w motor at 3s.