60V or 72V Sur Ron ASI BAC 4000 Controller 55MPH Full loom, Display Plug n Play


60V or 72V Sur Ron ASI BAC 4000 Controller 55MPH Full loom, Display Plug n Play

Out of stock



60V or 72V Sur Ron ASI BAC 4000 Controller 55MPH Full loom, Display Plug n Play


The same controller can be set for a milder standard battery tune (55 mph and much harder acceleration than a std Sur Ron) or a  much more powerful 72v (20) tune (your will need an upgrade battery for this)

Please state which tune state you want.


  • Plug and Play and Easy to Install
  • Plugs into the OEM harness and connectors, everything bolts on for a true play and plug install.
  • Keeps Original Throttle
  • Controller mounting bracket, bolts onto frame without modifications
  • Eco / Sport mode selector is now at: 2500W / 6000W respectively
  • Retains factory functions (Key Switch, lighting, USB charger, etc)


  • FOC (Field Oriented Control) for smooth throttle control and response, high efficiency,
  • Regenative braking that is variable using a second throttle for precise regen braking control, saves significantly on brake pad wear, and increases range by converting braking force and sending energy back into the battery.
  • Much more aggressive power, higher peak motor current compared to stock Sur Ron, improved starting torque and acceleration.
  • Higher top speed due to field weakening. Original controller would slow down nearing top speed, where as Field Weakening allows the motor to gain additional 1000rpm.
  • Controller operates in Hybrid mode (Uses hall sensors for smooth starting, then transitions to sensorless, increasing efficiency and gain in top speed)
  • Sensorless fallback mode in case the hall sensors were to fail
  • Can fully utilize regen (Sur Ron BMS will cut at full charge, however ERT has found a solution for this by limiting regen power at full charge and gradually increasing then restoring full regen power at battery % reaches 95%.
  • Controller is highly water resistant as is the high quality harness that has been designed in house by ERT to be reliable under all terrain environments.
  • Controller has automatic thermal rollback protection for the controller and the motor.
  • Motor RPM has increased from 5500rpm to 7000rpm.

                 Color Display

  • Color TFT Display is avaliable, with additional 3 mode power selection. Speedometer, ODO, Voltage, Wattage, Clock, etc
  • Eggrider Display with Bluetooth to smart phone giving option of power levels and accurate fuel range.

Eggrider Features:

  • Lightweight and compact design keeping your handlebar clean
  • Small enough to avoid unwanted attention
  • Dust and water resistant – IP65 protection
  • Voltage reading between 20V up to 60V
  • First to detect real battery capacity and tracking stats of up to 3 batteries
  • Android and iOS mobile apps for more statistics and configurations
  • Providing flexibility to comply with road e-bike laws worldwide
  • Ability to use the EggRider app as a larger display
  • In-depth charts capability for your rides
  • One button switch between two profiles
    • Throttle yes/no
    • Pedal assist yes/no
    • Power level


  • Size: 75mm x 47mm x 35mm
  • Weight: 31g
  • Cable length: 30cm
  • Handlebar mounting bracket: standard 22.2mm diameter
  • Physical buttons: Power On/Off, Level Up/Down and popular Road/OffRoad mode switch
  • Connector: Higo/Julet waterproof 5 pin male/female (see image)
  • Bluetooth low energy (BLE)
  • Compatible with e-bikes based on Bafang motors (including Sondors), Lishui and Kunteng controllers and many other brands we keep discovering
  • Hex bolt: M3
  • Mounting clamp pin: 2.0mm diameter and around 15mm length

Help and instructions:



Install videos:

Part 1,   https://youtu.be/D8_FVStCBHs

Part 2, https://youtu.be/RAMU6XfNkrI


UK distributor for ERT,

Photos and limitings courtesy of ERT