The ASI BAC555 motor controller is an ultra-compact AC motor controller (inverter) built for high-power electric bikes and light electric motorcycles. It suits Sur-Ron Light Bee and Talaria class machines. In addition, it works well in powerful electric scooters. The unit runs on a 24-52 V battery system and delivers 55 A continuous current with a 75 A peak.
This is a power electronics module, not a motor. It converts battery direct current into three-phase current and spins a brushless motor. It is not a battery, a charger or a display. Control comes from field-oriented control (FOC) running without position sensors, so Hall sensor wiring is not required.
The BAC555 sits at the top of the compact ASI BAC5xx family. Accelerated Systems Inc. (ASI), a Canadian electronics company based in Waterloo, Ontario, develops these controllers for light electric vehicles. Consequently, the BAC555 targets the highest commercial e-bike tier and pushes more power in demanding systems.
Key Benefits
- Sensorless vector control – the adaptive ASI algorithm works without Hall position sensors, which simplifies installation.
- Up to 120 % torque – the controller reaches up to 120 % of the motor rated peak stall torque.
- Automatic tuning – the controller identifies motor parameters on its own, so setup takes less time.
- 75 A peak current – a short-term power reserve supports acceleration and standing starts.
- Wide 24-52 V range – it accepts different battery configurations from 24 V through 52 V.
- IP65 sealing – the standard ingress rating is IP65, and sealed connectors raise it to IP67.
- TTL and Bluetooth protocols – both communication protocols are available for setup and data.
- 100 % factory testing – every controller is load-tested at the end of the production line.
Who Is This Controller For?
The ASI BAC555 is aimed at high-power electric bicycles and light electric motorcycles. It is widely used in Sur-Ron Light Bee, Talaria and similar light electric vehicle builds. Furthermore, it fits powerful electric scooters and utility light electric vehicles.
This controller is intended for experienced builders and workshops. Your system needs a compatible brushless motor plus a 24-52 V battery pack. A matching ASI BAC555 wiring harness is also required, and that harness is sold separately.
Before use, the controller must be configured with ASI BACDoor software. BACDoor app login credentials are not supplied, so a remote programming session has to be purchased. For that reason, this is not a universal plug-and-ride part.
Technical Specifications
| Model | ASI BAC555 |
| Manufacturer | Accelerated Systems Inc. (ASI), Canada |
| Type | Compact AC motor controller / inverter |
| Rated voltage | 24-52 V |
| Rated current | 55 A |
| Maximum (peak) current | 75 A |
| Control method | Field-oriented control (FOC) |
| Position sensors | Not required – adaptive sensorless control |
| Sensorless start | Adaptive |
| Automatic tuning | Yes |
| Torque | Up to 120 % of motor rated stall torque |
| TTL | Yes |
| Additional protocols | TTL + Bluetooth |
| Ingress protection | IP65 (IP67 with sealed connectors) |
| Quality control | 100 % factory load test |
| Configuration | ASI BACDoor software (login credentials not supplied) |
| Wiring harness | Sold separately |
Why Choose the ASI BAC555?
The BAC555 is the flagship of the compact BAC5xx line. It stands above the BAC500 and the BAC501. ASI developed it for the top commercial e-bike tier, so it delivers more power than the base versions in the same size class.
Instead of conventional Hall sensor control, the BAC555 relies on an adaptive sensorless algorithm. As a result, strong torque from zero rpm arrives without extra sensor cabling. Automatic motor parameter identification then shortens the tuning process for builders.
Sealing matters on light electric vehicles that see rain and dust. The IP65 housing covers standard riding conditions, while sealed connectors take the assembly to IP67. Moreover, every unit leaves the factory after a full load test.
Frequently Asked Questions
Does the BAC555 fit a Sur-Ron Light Bee?
- Yes, the BAC555 is designed for Sur-Ron Light Bee class machines.
- You still need a compatible brushless motor and a 24-52 V battery.
Can I use it on a Talaria or a powerful electric scooter?
- Yes, Talaria class light electric motorcycles are within its intended scope.
- High-power electric scooters and utility light electric vehicles also suit this controller.
Do I need Hall sensors on my motor?
- No, the adaptive sensorless algorithm runs without position sensors.
- This removes sensor wiring from the installation.
Is the wiring harness included?
- No, the ASI BAC555 wiring harness is sold separately.
- Order the harness together with the controller to complete the build.
How do I configure the controller?
- Configuration runs through ASI BACDoor software.
- BACDoor login credentials are not supplied with the unit.
- A remote programming session is therefore required before riding.
How much current does it deliver?
- Rated current is 55 A on a 24-52 V system.
- Peak current reaches 75 A for acceleration and standing starts.
How weatherproof is it?
- The standard rating is IP65.
- With sealed connectors, the assembly reaches IP67.
How does it compare with the BAC500 and BAC501?
- The BAC555 is the top model of the compact BAC5xx family.
- It supplies more power than those base versions in the same size class.
The ASI BAC555 gives experienced builders a compact, factory-tested vector controller for Sur-Ron Light Bee, Talaria and similar high-power light electric vehicles. Plan for the separate wiring harness and a BACDoor programming session, and this controller becomes the core of a serious 24-52 V drivetrain.
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