Installation & Connector Pinout
This guide covers the physical installation, wiring, and safety requirements for ASI BAC motor controllers.
Low Power 24-Pin Connector
The primary connector for BAC355/555/855 controllers includes these signal assignments:
Hall Sensors (Pins 1-6)
| Pin | Function | Specification |
|---|---|---|
| 1-3 | Hall A, B, C | 5V Pulled-up, active low |
| 4-6 | Hall Ground | Withstand Voltage: 100V |
Power Outputs
| Pin | Function | Specification |
|---|---|---|
| 11 | 5V Supply | Polyfuse protected, 50mA max |
| 13 | 12V Supply | Polyfuse protected, 50mA max |
| 21-22 | Battery Enable | Up to 400mA current |
Communication Pins
| Pin | Function | Notes |
|---|---|---|
| 17-18 | TTL Serial | Direct serial communication |
| 19-20 | CAN Bus | Configurable 120Ω termination |
Input/Output Functions
- Cruise control input
- Brake inputs (Brake 1, Brake 2)
- Throttle (0-5V analog)
- Switchable lighting output
High-Power Connectors
6-Pin Molex MX150
- Hall sensor interface
- Brake input support
16-Pin Molex MX150
| Function | Specification |
|---|---|
| HDQ low-side switch | For BMS communication |
| Dual TTL channels | Serial communication |
| Analog inputs | 0-5V range |
| CAN communication | With termination option |
| Ground | 400mA max shared |
Motor Connector
Phase wiring follows U/V/W (or A/B/C) convention:
| Connection | Notes |
|---|---|
| Phase U (A) | Motor phase 1 |
| Phase V (B) | Motor phase 2 |
| Phase W (C) | Motor phase 3 |
| Hall signals | Dedicated sensor wiring |
| Brake input | Configurable 5V pull-up |
Wire Gauge
Wire gauge varies by controller model. Always verify ampacity requirements for your specific application and use appropriately rated cables.
EMC/EMI Compliance
Responsibility
Final responsibility for passing EMC/EMI compliance tests lies with the integrator. Performance depends on:
- Motor controller design
- Wiring and grounding
- Enclosure design
- Component selection
Standards Priority
When guidance conflicts, prioritize in this order:
- Industry Regulations (ISO, UL, CE, EN)
- Industry Standards (IEEE, ANSI)
- Application-Specific Guidelines
- General Engineering Judgment
Wiring Best Practices
Power Wiring
Size Cables Appropriately
Use cables rated for your maximum continuous current to minimize resistance and heat generation.
Minimize Wire Length
Keep wires short to reduce inductance and voltage spikes during switching.
Twist Battery Leads
Twist B+ and B- leads tightly together to reduce electromagnetic radiation.
Twist Motor Phase Wires
Twist U, V, W motor wires together to minimize magnetic field radiation.
Route Within Frame
Position wiring within the vehicle frame, preferably low and central.
Apply Ferrite Beads
Add ferrite beads to noisy or unshielded wires where EMI is a concern.
Signal Wiring
| Practice | Application |
|---|---|
| Use twisted pair | CAN-H/CAN-L differential signals |
| Twist with ground | Single-ended signals |
| Maintain separation | Keep power and signal wires apart |
| Cross at 90° | When power/signal must cross |
| Shield signal wires | Connect shield at controller end only |
| Terminate unused inputs | Prevent floating states |
Grounding Strategy
- Keep power ground (B-) and signal ground (GND) separate outside the controller
- Use galvanic isolation (opto-isolators) for noise-susceptible lines
- Bond chassis to B- using a Y-class safety capacitor
- Ensure shields and enclosures form electrically continuous systems
Protection & Fusing
Fuse Selection
| Fuse Type | Application |
|---|---|
| Blade fuses | Automotive, medium-current |
| Resettable PTCs | Low to mid-power, reusable |
| Fast-blow | Sensitive electronics |
| Slow-blow | Motor startup surge tolerance |
Critical: Ampere Interrupting Capacity (AIC)
The fuse's AIC must exceed the maximum potential fault current from your battery system.
Safety Warning
Inadequate AIC ratings risk fuse explosion or failure to clear faults safely. Always verify your fuse can interrupt the maximum available fault current.
Rating Guidelines
- Voltage rating: Must equal or exceed system voltage
- Current rating: 125-150% of maximum continuous current (verify against application specs)
Fuse Placement
- Primary fuse connects between battery positive terminal and controller input
- Do not fuse individual motor phases - partial operation can cause severe damage
Reverse Polarity Protection
ASI controllers support regenerative braking, meaning current must flow bidirectionally between controller and battery.
No Series Diodes
Simple series diodes are unsuitable as they block regenerative current, potentially causing overvoltage faults.
Recommended Solutions
- Ideal diode bridges using N-Channel MOSFETs
- Contactors with polarity detection
Capacitor Inrush Protection
Method 1: Pre-Charge Circuit (Recommended)
Uses a power resistor and contactor:
- Initial power flows through resistor, limiting inrush
- Capacitors charge gradually
- Main contactor bypasses resistor for normal operation
Method 2: NTC Thermistor
- High initial resistance decreases with heat
- Pair with bypass relay for higher-power systems
- Risk of overheating without bypass
Method 3: Soft-Start Circuit
Gradually ramps current using resistors, capacitors, and MOSFETs.
Battery Disconnection Warning
Critical Safety
Disconnecting the battery while the motor is actively regenerating can cause extremely high voltage spikes that may damage components.
Protection Methods
- Add bulk capacitors for temporary power during disconnection
- Implement undervoltage fault detection for graceful shutdown
- Use inrush limiting during reconnection
Software Protections
The controller protects against:
- Output instantaneous overcurrents
- Temperature-based power limiting
- Motor power and current limits
- Battery current and temperature constraints
- Motor temperature or I²T-based overload
Testing Requirements
Pre-Power Verification
- Verify polarity of all connections
- Confirm fuse installation
- Check for short circuits
Initial Startup
- Use current-limited bench supply
- Monitor inrush behavior
- Check temperature and voltage rails
Fault Simulation
Test the following scenarios:
- Short circuits
- Overcurrent conditions
- Thermal events
- Battery disconnection/reconnection
- OVP and UVLO trigger points
Safety Responsibility
Safety is the sole responsibility of the system integrator. Compliance with ISO, IEC standards, formal risk assessment (FMEA), and comprehensive validation testing is recommended for each application.
Next Steps
- Configure Battery Settings for your voltage and current limits
- Set up Protection Systems for safe operation
- Review Communication Protocols for network integration