Electric Power Steering (EPS) is standard on almost every new car today. But when you convert an older vehicle to electric, the aftermarket EPS kit you choose determines whether your steering feels light and responsive or heavy and dangerous. Here's how to pick the right system for your build.
3 Types of EPS for EV Conversion
| Type | How It Works | Best For | Power Draw | Torque Output |
|---|---|---|---|---|
| C-EPS (Column Assist) | Motor mounted on the steering column inside the cabin | Light vehicles under 1,200 kg (Beetle, Miata, classic cars) | ~180W | Low — suitable for light front axle load |
| R-EPS (Rack Assist) | Motor mounted directly on the steering rack | Medium vehicles 1,200-2,200 kg (Tacoma, Explorer, SUVs) | ~360W | High — handles heavy front axle load |
| EHPS (Electric Hydraulic) | Electric pump pressurizes hydraulic fluid to assist the rack | Heavy vehicles over 2,200 kg (trucks, buses, commercial) | 500W - 3kW | Highest — designed for commercial duty |
C-EPS vs R-EPS vs EHPS: Which One Does Your Conversion Need?
C-EPS — Column Assist
The motor is integrated into the steering column, usually below the dashboard. It's the simplest to install in an EV conversion because it doesn't require modifying the steering rack or hydraulic lines.
- CMVTE part: 12V 180W EPS kit — plug-and-play, torque sensor integrated, CAN bus optional
- Installation: 3-5 hours — column-mounted, no rack modification needed
- Cost: $350-$600
- Best donor vehicles: VW Beetle, Mazda Miata, classic Mini, Porsche 914, any lightweight car
R-EPS — Rack Assist
The motor is mounted directly on the steering rack, providing higher assist torque. Required for heavier vehicles where column assist isn't strong enough.
- CMVTE part: 12V 360W EPS kit — higher torque output, includes rack mounting hardware
- Installation: 6-10 hours — requires removing and modifying the steering rack
- Cost: $600-$1,200
- Best donor vehicles: Toyota Tacoma, Ford Explorer, Jeep Wrangler, SUVs and light trucks
EHPS — Electric Hydraulic
Uses an electric pump to push hydraulic fluid, giving the feel of traditional hydraulic steering without the engine-driven belt pump. Best for heavy vehicles where electric motors can't generate enough torque.
- CMVTE part: EHPS pump + controller kit — 12V or 540V options
- Installation: 4-8 hours — mount pump, run hydraulic lines to existing rack
- Cost: $500-$2,000 depending on voltage and pump size
- Best donor vehicles: Heavy trucks, buses, commercial EVs, full-size SUVs over 2,500 kg
EPS Selection by Vehicle Weight
| Front Axle Weight | Recommended EPS Type | CMVTE Kit |
|---|---|---|
| Under 600 kg | C-EPS (Column) | 180W kit |
| 600-900 kg | C-EPS or R-EPS | 180W or 360W kit |
| 900-1,300 kg | R-EPS (Rack) | 360W kit |
| Over 1,300 kg | EHPS | EHPS pump + controller |
Why EPS Matters More in an EV Conversion
In a gas car, the engine provides a stable 12V power source through the alternator. In an EV conversion, your 12V system runs off a DC-DC converter. If your EPS draws too much current for your DC-DC, you'll get voltage sag that affects your controller, BMS, and lights.
Rule of thumb: Size your DC-DC converter to handle the EPS peak current plus all other 12V loads. A 1 kW DC-DC is sufficient for C-EPS systems; 1.5-2 kW is recommended for R-EPS or EHPS.
EPS Installation Tips for EV Conversions
- Mount the control module away from heat — the EPS controller generates heat; keep it away from the motor controller and radiator
- Use a dedicated relay — the EPS motor draws high inrush current; wire it through a 40A relay triggered by ignition power
- Torque sensor calibration — after installation, center the steering wheel and run the auto-calibration routine per the manual
- CAN bus integration (optional) — CMVTE's EPS kits support CAN bus communication with our motor controller and display for speed-sensitive steering
Get the Right EPS for Your Build
Tell us your vehicle weight, steering column type (collapsible or solid), and whether you need CAN bus integration. We'll send the correct EPS kit with wiring diagram and installation guide.
WhatsApp / Phone: +86 181 2358 8272
Email: [email protected]
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