BeeLatch ships October 18BeeDash for Android — APK available now: text 415.341.2281
EMGElectric Moto GarageConnected motorcycle tech
BeeDashBeeLatchDemoReviverChargerServicesGuidesPartsShopGet the BeeDash app
Service in setup · pricing TBD

SURRON Ultra Bee · controller service

Ultra Bee OEM controller flashing

Unlock the stock Ultra Bee controller with custom firmware: much more power and speed, and far more again with an aftermarket battery. Firmware by Aleksandr Valov, flashing done by Electric Moto Garage in San Francisco.

Register interestHow it works

A collaboration

The firmware is written by Aleksandr Valov (Александр Валов), who spent a long time getting a custom firmware for the stock UB25 controller right. Because of his location, Electric Moto Garage will offer the flashing service. Licensing and cost are still being worked out between us.

What you get

  • No built-in power or speed limit: the ceiling becomes your battery and the controller’s hardware
  • Much more power with an aftermarket battery
  • Reworked throttle and ride modes
  • Tune and monitor with VESC Tool; BeeDash support for VESC is planned
The numbers

What the developer reports

These are the developer’s figures, not ours, and we have not independently verified them. Temperature is still one factor that limits power.

StockCustom firmware
Peak powerabout 21 kWabout 50–52 kW
Continuous powerabout 18 kWabout 32 kW
Top speedabout 95 km/hup to 140 km/h (bench-tested only so far)
Phase current limit—800 A, set below the 920 A (868 A at 100 °C) the manufacturer lists for the power switches

On the stock battery, the developer says the practical ceiling is about 27–28 kW with brief peaks of 30–32 kW. The highest figures need an aftermarket battery. His approach was to check the controller’s hardware limits first (power switches, capacitors and other parts) and leave a safety margin, rather than only raising numbers.

How it works

Not an easy modification.

I built a special jig that connects straight to the controller’s circuit board. To reach it, the heat sink is carefully removed and the thermal potting is cleared from a few areas.

  1. Send in your controller

    Contact us first. You ship the controller to our San Francisco lab.

  2. Read its UUID

    Each controller has its own UUID. It is sent to the firmware developer, who compiles firmware for that exact controller.

  3. Open it up

    Heat sink off, potting cleared where needed, jig attached to the board.

  4. Flash and test

    The custom firmware is loaded and checked.

  5. Back to you

    Turnaround is 1–3 days once your controller reaches the San Francisco lab. Shipping time is extra.

Read this first. This is for off-road use only. More power means more heat and more wear, and flashing may void your warranty. It is a risky modification that can damage the controller or the bike, and results are not guaranteed. Riding fast is dangerous: wear proper protective gear and ride within your ability. Licensing, cost and terms are still to be agreed.
Behind the scenes

From the bench

Photos and notes from the development work.

Cover off: the stock controller’s power section, with the main capacitors, under thermal potting.
Cover off: the stock controller’s power section, with the main capacitors, under thermal potting.
The stock Ultra Bee controller, with its finned cover lifted off the board.
The stock Ultra Bee controller, with its finned cover lifted off the board.
Close-up of the stock control board and its microcontroller.
Close-up of the stock control board and its microcontroller.
Bench setup: the board with wires attached for programming and testing.
Bench setup: the board with wires attached for programming and testing.
Two ICs on the control board, highlighted for reference.
Two ICs on the control board, highlighted for reference.
Reverse-engineering notes: the phase-current and over-voltage comparator circuit (LM339 and 4048 logic).
Reverse-engineering notes: the phase-current and over-voltage comparator circuit (LM339 and 4048 logic).
Oscilloscope capture during bench testing.
Oscilloscope capture during bench testing.
Microcontroller pin-out reference with handwritten notes (S32K142, LQFP-64).
Microcontroller pin-out reference with handwritten notes (S32K142, LQFP-64).
Several controllers on the bench.
Several controllers on the bench.
An example VESC Tool real-time data screen: the kind of tool you can use with the flashed controller.
An example VESC Tool real-time data screen: the kind of tool you can use with the flashed controller.
Interest list

Want your controller flashed?

Leave your email and you’ll hear when pricing and terms are set and the service opens.

Electric Moto Garage is independent and is not affiliated with, sponsored by, or endorsed by SURRON / Qiulong Technology. SURRON is a trademark of its owner. The custom firmware is the work of its developer.

BeeDashBeeLatchBee ChargerGuides