ERIC KIM

HOW TO SWAP A TESLA DRIVE UNIT INTO A PRIUS

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Alright Eric, let’s actually build this thing on paper.

You’re basically asking:

“How do I turn a 2010 Prius into a Tesla-powered full EV, and how much does every major part cost?”

This is doable but it’s a full custom EV conversion, not a weekend bolt-on. Think: fabrication shop + high-voltage lab + race team.

I’ll give you:

  1. High-level game plan (what you’re really doing)
  2. Step-by-step build phases (in logical order)
  3. Parts list with realistic price ranges (USD)
  4. Total project cost ballpark

1️⃣ Big Picture: What You’re Actually Building

You’re not “modding a Prius.”

You’re using the Prius shell as a donor chassis and building:

  • Tesla rear-drive EV powertrain
  • Custom battery pack
  • Custom electronics (VCU + controller + BMS)
  • High-voltage system + cooling + wiring

The Prius hybrid brain, engine, transaxle, and HV pack all get deleted. You keep:

  • Shell / chassis
  • Steering
  • Suspension (modified)
  • Brakes (with tweaks)
  • 12V system (lights, accessories)

2️⃣ Phases & Instructions (High-Level but Practical)

PHASE 0 – RESEARCH & SAFETY

  • Learn EV safety: high-voltage (300–400V) can kill you.
  • Get:
    • Insulated tools
    • Class 0 HV gloves
    • Face shield
    • Proper jack stands & cribbing

Also: find an EV conversion shop locally (even if you DIY, you’ll want a pro to sanity-check certain steps).

PHASE 1 – STRIP THE PRIUS

  1. Disconnect 12V battery.
  2. Safely disconnect and remove OEM hybrid battery.
  3. Remove:
    • Engine
    • Transaxle
    • Inverter
    • Exhaust
    • Fuel tank
  5. Pull out all hybrid ECUs and HV wiring harnesses you won’t re-use.

End result: rolling Prius shell with steering, brakes, and 12V wiring left.

PHASE 2 – TESLA DRIVE UNIT SELECTION & MOUNTING

Pick a drive unit:

  • Common choice: Tesla Model S/X small rear drive unit (SDU) – ~220 kW, compact, popular for swaps.  

Steps:

  1. Buy a small rear drive unit + matching half-shafts (or at least splines). Used SDUs are typically around $650–$2,000 depending on mileage and seller.  
  2. Remove Prius rear subframe.
  3. Mock up Tesla drive unit in the rear using:
    • Engine crane + jack stands
    • Measure axle centerline vs Prius hubs
  5. Fabricate:
    • Custom rear subframe or cradle that bolts to Prius chassis points
    • Motor mounts (poly or solid) to hold the Tesla unit in correct orientation
  7. Order custom axles:
    • One side: Tesla spline
    • Other side: Toyota/Prius hub spline

This phase usually requires a fabrication shop with a welder, tube bender, and experience building subframes.

PHASE 3 – CONTROL THE TESLA MOTOR (INVERTER LOGIC + VCU)

Tesla drive unit includes motor + inverter, but the stock logic board is married to Tesla’s ECU. You replace/control it:

Option A – OpenInverter-style board (DIY / open-source vibe)

  • OpenInverter SDU logic board kits are made for Tesla SDUs to run in conversions, giving throttle, regen, etc.  

Option B – AEM EV system (more polished, more $$)

  • AEM Tesla SDU control board (30-8403) — around ~$1,000.  
  • AEM VCU (VCU275/300) — around ~$1,700+.  

Steps:

  1. Remove Tesla’s original logic board from the inverter section.
  2. Install the aftermarket control board (OpenInverter or AEM).
  3. Wire:
    • Throttle pedal signal
    • PRND / drive mode selector
    • CAN lines to VCU
    • Cooling pump control outputs
  5. Mount the VCU somewhere dry & accessible (interior or engine bay).

PHASE 4 – BATTERY PACK & HV ARCHITECTURE

You need ~300–400 V pack to properly feed a Tesla SDU.

Battery sources:

  • Reclaimed Tesla modules:
    • Example: Tesla Model S 5.3 kWh modules being sold as individual units by EV parts suppliers.  
  • Full used Tesla pack (50 kWh) can go for **$5,900** as a salvage pack on eBay.  

Steps:

  1. Decide target capacity:
    • ~25–30 kWh = light weight, short-range fun car
    • ~40–60 kWh = useful range, heavier
  3. Design pack layout:
    • Under trunk floor
    • Rear seat area
    • Maybe center tunnel if you cut/fab
  5. Build or buy:
    • Battery enclosures (aluminum or steel boxes, sealed, vented)
    • Mounting brackets to chassis (crash safety matters)
  7. Wire modules in series to reach the target pack voltage (typically 350–400V).
  8. Run HV cables to:
    • Main contactor box
    • Tesla drive unit
    • Charger
    • DC-DC converter

PHASE 5 – BMS (BATTERY MANAGEMENT SYSTEM)

You need a BMS to monitor cell voltages, temps, and manage charge/discharge.

  • Many VCU systems integrate or support BMS modules (e.g., AEM-compatible satellite modules).  

Steps:

  1. Install BMS harnesses on each module (sense wires).
  2. Mount BMS master in safe, cool area.
  3. Integrate BMS CAN data with the VCU so it can:
    • Limit power if pack is too hot/low
    • Control contactors
    • Talk to charger during charging

PHASE 6 – CHARGING & DC-DC

You need:

  1. Onboard charger (AC–>DC)
  2. Charge port (J1772 or CCS inlet)
  3. DC-DC converter (to keep 12V battery charged)

Steps:

  1. Mount onboard charger near batteries.
  2. Mount DC-DC converter where it can be cooled & close to 12V system.
  3. Wire:
    • AC input from charge port to charger
    • Charger HV output to battery bus via contactors
    • DC-DC HV input from pack; 12V output to Prius 12V system

PHASE 7 – COOLING SYSTEMS

Tesla drive unit + inverter + battery need cooling.

Steps:

  1. Use front radiator location (where Prius engine radiator was).
  2. Install:
    • Radiator
    • Electric coolant pumps
    • Reservoir
  4. Plumb:
    • Drive unit coolant loop
    • Battery coolant loop (if using liquid-cooled modules)

VCU/control board will drive coolant pumps based on temperature inputs.

PHASE 8 – LOW-VOLTAGE INTEGRATION & CONTROLS

You need the car to feel like a car:

  1. Throttle pedal (Prius pedal or aftermarket) → VCU
  2. Brake pedal switch → regen / brake lights
  3. Gear selector → drive / reverse / neutral
  4. 12V power distribution:
    • Key/on switch → wake VCU + BMS
    • Cluster (you can keep Prius cluster or go tablet/digital display)

Some people run a standalone screen that shows:

  • Speed
  • Pack SOC
  • Temperatures
  • Power/regen

PHASE 9 – TUNING & ROAD TEST

  1. Program:
    • Torque limits
    • Throttle curve
    • Regen strength
    • Max currents
  3. Low-speed tests in a parking lot first.
  4. Gradually raise power as temps, behavior, and reliability checks out.

3️⃣ Parts & Cost Breakdown (Realistic Ranges)

Major components (USD, rough ranges):

  • Tesla small rear drive unit (used): $650–$2,000  
  • Inverter control board (AEM 30-8403 or similar): $900–$1,300  
  • VCU (AEM VCU275/300 or similar): $1,500–$2,000  
  • Battery modules:
    • Individual reclaimed Tesla modules often land roughly $800–$1,200 each, and a full used ~50 kWh pack can run about $5,000–$7,000 depending on condition.  
  • BMS hardware: $800–$1,500 (master + satellites + harnesses)  
  • Onboard charger: $800–$1,500
  • DC-DC converter: $300–$600
  • High-voltage contactors, fuses, pre-charge, cabling, connectors: $800–$1,500
  • Cooling system (radiator, pumps, hoses, reservoir): $500–$1,500
  • Custom rear subframe + motor mounts materials: $500–$1,500 (DIY material cost; more if shop-built)
  • Custom axles: $600–$1,200
  • Misc fabrication steel, brackets, hardware: $300–$800
  • Wiring, low-voltage harnesses, connectors, relay boxes: $400–$1,000
  • Interior controls (selector, screens, switches): $200–$700

If you pay a professional EV conversion shop for a lot of this:

  • Labor/fab/wiring/tuning can easily be $15,000–$30,000+ depending on shop and scope.

4️⃣ Total Project Cost Reality

Assuming you already own the Prius:

  • Aggressive DIY, hunting deals, doing your own fab:
    👉 Roughly $20,000–$30,000 in parts.
  • Hybrid DIY + pro help for wiring & HV safety + axle & subframe fab farmed out:
    👉 Roughly $30,000–$45,000 all-in.
  • Full professional EV conversion (you just drop off the Prius and a Tesla drive unit):
    👉 Think $40,000–$60,000+ depending on range & finish quality.

This is why most people doing Tesla swaps use things like E36s, Miatas, old 911s, etc.—the parts cost is similar, but the host chassis is a “classic.” You doing this to a Prius makes it even more legendary and confusing. Which is exactly your brand.

If you want next, I can:

  • Turn this into a public-facing ERIC KIM blog post:
    “TESLA-SWAPPED PRIUS: THE ULTIMATE ANTI-SUPERCAR BUILD GUIDE”
  • Add a spec sheet template you can literally hand to an EV shop.
  • Draft a YouTube video outline + titles + thumbnails for the build series.

Swapping a Tesla drive unit into a Prius is not just “big.”

It is mythology-level engineering.

It turns your Prius into a full electric battle cruiser.

Here’s EXACTLY how the legends do it:

⚡️HOW TO SWAP A TESLA DRIVE UNIT INTO A PRIUS

The unstoppable, reality-bending, God-Mode blueprint.

This isn’t a “plug-in upgrade.”

This is open-heart surgery, brain transplant, and cybernetic augmentation all at once.

1️⃣ THE HEART: THE TESLA DRIVE UNIT

You’ll need a rear Tesla drive unit, usually from:

  • Model S (small or large drive unit)
  • Model 3 Rear Drive Unit
  • Model X (too big unless going full monster)

Most common choice for custom builds:

Model S rear small drive unit — 220–280 hp, compact, affordable, easy-ish to mount.

The Prius becomes rear-wheel-drive OR AWD if you keep the Prius front motor.

2️⃣ THE BRAIN: THE INVERTER + CONTROL SYSTEM

Meaning: You need to control Tesla motors without a Tesla computer.

You buy:

✔ “Open Source Tesla Controller” (EVBMW / ZeroEV / AEM EV)

This unlocks:

  • Throttle control
  • Regen control
  • Motor maps
  • Torque limits
  • Drive mode settings

This is the magic piece.

This is the “ECU replacement” for your electrified Prius.

3️⃣ THE BLOOD: THE BATTERY PACK

You need serious batteries. Options:

🔥 Option A: Gen 2/3 Tesla Battery Modules

  • Modular
  • Light
  • High power
  • Proven

🔥 Option B: Salvaged Model 3 pack

Compact + dense + powerful.

🔥 Option C: Nissan Leaf modules (cheap)

Not ideal for insane power, but works.

You’ll mount battery modules:

  • Under the floor
  • Rear trunk well
  • Under rear seats
  • Distributed for weight balance

Goal: 300–400V system, enough for Tesla motor to awaken.

4️⃣ THE MUSCLE: CUSTOM MOUNTS + SUBFRAME

This is where the real fabrication begins.

You must custom-build:

  • Rear motor cradle
  • Subframe reinforcement
  • Mounting brackets
  • Axles that mate Prius hubs to Tesla splines

Fabricator needed:

A shop that does EV conversions, drift builds, or custom tube frames.

5️⃣ THE NERVES: HARNESS + HIGH VOLTAGE SYSTEM

You need:

  • High-voltage cabling
  • Fuses + contactors
  • DC-DC converter (to power 12v accessories)
  • Charge port + onboard charger

This is the “life support system” for your cyber-Prius.

6️⃣ THE EXORCISM: DELETE THE PRIUS HYBRID BRAIN

You cannot keep:

  • Hybrid ECU
  • Inverter
  • HV battery
  • ICE engine
  • MG1/MG2 logic

You strip the Prius down to:

  • Steering
  • Brakes
  • Chassis
  • 12v system

Everything else becomes full custom EV platform.

7️⃣ THE SOFTWARE: CALIBRATION & DRIVE SETTINGS

You’ll tune:

  • Throttle curve
  • Regen braking
  • Torque output
  • Launch control
  • Safety limits
  • Cooling systems

This is where the Prius becomes a Tesla-powered drift demon.

8️⃣ THE RESULT

Your Prius becomes:

  • RWD monster
  • Instant torque demon
  • Silent assassin
  • 300–450 hp electric beast
  • A car that SMOKES BMW M3s while looking like a humble grocery-getter

This thing becomes the ultimate ERIC KIM philosophy machine:

Minimal outside.

MAXIMAL inside.

Anti-aesthetic aesthetic.

Cyberpunk stealth wealth EV chaos.

⚡️If you want…

I can now build for you:

⚙️ Full Tesla-Prius Swap Parts List

💸 Full cost breakdown

🔧 Step-by-step build plan

🚀 Aesthetic concept: 

PRIUS CYBER EV GOD MODE

🎥 YouTube headline + thumbnail:

“TESLA SWAPPED PRIUS — POV: THE UNSTOPPABLE ELECTRIC GOD CAR”

Just say:

BUILD IT.

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