Building an EV from a Classic Car

Building an EV from a Classic Car: The Smart Architecture Behind Carmoddy

Introduction

Converting a 1992 Ford Escort into an electric vehicle sounds complex, but the Carmoddy project demonstrates elegant engineering: smart component reuse. Rather than inventing new solutions, this conversion leverages proven Nissan Leaf technology with millions of miles of real-world validation—offering green energy enthusiasts a practical blueprint for their first EV conversion.

Why Nissan Leaf Components?

The Carmoddy conversion uses complete Leaf systems (Motor EM57: 110 kW, 320 Nm torque; 24-30 kWh battery; integrated controller) rather than sourcing random parts. This delivers three critical advantages:

1. Complete System Integration: Components were engineered to work together, not cobbled from disparate sources

2. Mature Technology: Lithium-ion batteries are well-understood with established safety practices

3. Production Testing: 5+ million Leaf vehicles means failure modes are identified and eliminated

Mechanical Architecture: Elegant Simplicity

Motor Placement: Engine Bay

Mounting the Leaf motor in the original engine bay (rather than trunk) preserves:

- Structural foundation already engineered for heavy components

- Weight distribution (maintaining front-heavy classic car balance)

- Thermal management (factory radiator/fans prove over-engineered for efficient motors)

- Electrical routing (short high-voltage cable runs reduce losses)

Half-Shaft Design

The critical challenge: Leaf transmission outputs differ from Escort axle specifications. Solution: Commission professional driveline fabrication (~$800-$1,200) for custom half-shafts matching both systems with proper CV joints rated for 320 Nm. This single investment beats DIY attempts by ensuring perfect alignment permanently.

Battery: Distributed Design

Rather than one large pack, Carmoddy splits 650 lbs across two locations:

- Primary (18-24 kWh): Gas tank cavity—structurally reinforced, impact-protected

- Secondary (6-12 kWh): Trunk—extends range to 200+ miles, improves handling via lower center of gravity

Benefits: Load distribution for balanced handling, better thermal dissipation, modular expansion capability, redundancy if one enclosure is damaged.

Thermal & Electrical Systems

Cooling

Traditional engines waste 70% of fuel energy as heat. Electric motors (~95% efficient) need minimal cooling. Carmoddy reuses the original radiator plus adds:

- 12V electric pump (~$150)

- Thermostatic valve (~$75)

- Temperature monitoring (~$45)

Total cost: ~$300 vs. custom design ($1,000+).

Electrical Architecture

High-Voltage (360V DC): Redundant safety with multiple disconnection points:

- Service disconnect (manual emergency)

- Main contactor (automatic, ignition-controlled)

- BMS interlock (battery-condition triggered)

- Inertia switch (impact-triggered)

Low-Voltage (12V): Original Escort 12V system remains largely intact with DC-DC converter supplying power. This avoids redesigning every accessory—reducing complexity 80%.

Cost & Reliability Analysis

Cost Comparison

Component |Carmoddy | Custom |

Motor + Controller | $600-$1,800 | $13,000+ |

Battery | $2,000-$5,000 | $8,000-$15,000 |

Transmission | $300-$600 | $5,000+ |

Half-Shafts | $600-$1,200 | $2,000+ |

Total Drivetrain | $3,500-$8,600 | $28,000+ |

The math: Salvage approach costs ~70% less than custom engineering while maintaining superior reliability.

Reliability Advantage

Production Leaf vehicles provide tested baselines:

- Documented failure modes

- Mature supply chain for parts

- Community troubleshooting resources

Custom components offer none of these advantages.

Engineering Excellence

Reuse Strategy

Rather than reinventing, Carmoddy:

- Maintains original 13" wheels/suspension geometry

- Adapts existing brake system (adds electric vacuum pump)

- Keeps power steering hardware (adds 12V pump)

- Preserves interior electrical systems

Modular Battery Architecture

48 individual modules allow:

- Phased installation (start partial, expand later)

- Individual failure isolation (BMS monitors each module)

- Module-level redundancy (system survives single failures)

- Simple maintenance (replace one failed module, not entire pack)

Multi-Layer Safety

Multiple disconnects aren't redundant—each serves specific functions:

- Human control (service disconnect)

- Automatic distribution (main contactor)

- Condition monitoring (BMS interlock)

- Accident protection (inertia switch)

Failure of any single component still allows emergency shutdown via others.

Performance Reality

- Range: 60-90 miles (realistic for 24 kWh pack at 60-90 Wh/mile efficiency)

- Acceleration: 0-60 in ~10 seconds (320 Nm torque feels quick for 2,400 lb car)

- Efficiency: 30+ MPGe equivalent ($0.03-$0.05/mile fuel cost vs. $0.10-$0.15 for gas)

- Charging: Level 2 (240V) charges in 4-6 hours for $2-$3

Beginner-Friendly Approach

This conversion succeeds for new builders because:

1. Proven components with documented failure modes

2. Community expertise from thousands of Leaf/EV owners

3. Modular testing (test subsystems independently before integration)

4. Professional fallbacks (driveline, welding, electrical work are standard services)

5. Scalability (start simple, add features incrementally)

Sustainability Impact

Circular economy benefits:

- Salvage Leaf components (extend vehicle lifespan)

- Reuse 15+ year old Escort body (avoid new manufacturing)

- Preserve interior (no waste from gutting)

Lifetime carbon analysis:

- Avoided manufacturing emissions: ~15 tons CO₂

- EV operation reduces emissions 50-70% vs. gas

- 20+ year extended vehicle life vs. 5-10 years typical

Carbon payback: 2-3 years of driving.

Challenges & Reality Check

- Salvage availability: Nissan Leaf supply won't last forever

- Limited spares**: Replacement components may become scarce as Leafs age

- No OEM warranty: All repairs are self-funded

- Effort required: Real fabrication/welding/electrical integration needed

- Regulatory uncertainty: Vehicle conversion laws vary by location

The Bottom Line

Carmoddy succeeds through engineering pragmatism: leverage proven components rather than invent new ones.

Results:

- ✅ 70% cost savings vs. custom engineering

- ✅ Proven reliability over untested design

- ✅ Beginner-friendly modular architecture

- ✅ True sustainability (circular economy)

- ✅ 60-90 mile range at $0.03-$0.05/mile

For green energy enthusiasts, this approach proves: don't redesign what's already working. Build on proven foundation.