Golden Revolution: A Tesla-Powered 1980 Mercedes Benz

David Rosenstraus’ Tesla-Powered 1980 Mercedes 300CD

Conversions of diesel vehicles to electric are quite rare, especially in the U.S., but David Rosenstraus’ 1980 Mercedes 300CD is a spectacular way to make an entrance into the retrofit game. Based in Boca Raton, Florida , his 300CD has become a stunning example of what’s possible when old-world luxury (and bling) meets cutting-edge EV performance. With a Tesla Model S LDU in the back, a sleek AMG replica body kit, and plans for a brand-new battery upgrade, David has built something we’d all desire—despite never thinking we’d ever want a golden Mercedes!

A Project Born of Passion

David is no stranger to car enthusiasts, and his Tesla-powered 300CD has already turned heads across the EV and classic car communities over the past three years. The project began with a deep appreciation for the timeless design of the Mercedes W123 chassis, which is beloved for its durability and understated elegance. However, as a visionary with a love for innovation, David saw potential beyond its stock diesel engine. “I’ve always admired the design of the 300CD, but I wanted to take it to the next level—something sustainable and fast, but still true to the spirit of the car,” he says. “The idea was to keep the car’s classic look while giving it a modern electric drivetrain that could deliver on both power and efficiency.”

To bring this vision to life, David opted for a Tesla Model S LDU (Large Drive Unit), delivering the kind of acceleration that no one would expect from a car born in 1980. The swap was a challenging and meticulous process, requiring a skilled hand and a deep understanding of electric powertrains and classic car architecture. David started the year-long swap in 2020 in his shop in Pittsburgh, Pennsylvania. Enjoying the build process of the EV swap led David to join the team at Salvage 2 Savage as lead fabricator—the group behind Mike Rolleri’s twin Tesla-powered all-wheel-drive electric 1985 Chevy C10 truck that made waves at the 2021 SEMA show. “The Tesla swap was the key to making this project viable,” David explains. “You get that immediate power delivery, but it’s also smooth and quiet. It’s everything you’d want in a modern car but in a classic package.” Complementing the drivetrain is a cooling system upgrade that ensures the Tesla motor and battery systems remain at optimal temperatures. The new setup includes dual cooling reservoirs and fans, originally sourced from a Chevy Volt, ensuring the battery pack and the Tesla drive unit always perform at their best, even on hot Florida days. Additionally, a Chevy Volt DC-to-DC converter maintains the traditional 12-volt system, powering all accessories like lights, fans, and stereo components. David didn’t stop with just performance upgrades.

AMG Transformation

Along with new custom rims by Rotiform, taking inspiration from its  VCE-T design, provided by St. Paul Speed, which adds a modern twist while keeping the car’s period-correct appearance, David has also paid close attention to the car’s lines and aesthetics. One of the most significant visual transformations of David’s Mercedes comes from the addition of a custom-made AMG replica body kit. Originally, U.S.-imported Mercedes models from the 1980s came with large, ungainly bumpers to meet strict safety regulations. While functional, these bumpers detracted from the car’s sleek design. “I’ve always been a fan of the Euro-style bumpers,” David shares. “They’re smaller, more tucked in, and make the car look sharper. I wanted to bring back that original look but also give it a sportier edge.”

The AMG replica body kit, sourced from Classic Euro Parts, completely changes the character of the 300CD. Made from lightweight composite materials, the new bumpers and side skirts give the car a lowered, aggressive stance. Fitting the kit required painstaking attention to detail, including custom adjustments to ensure that every piece fit seamlessly against the factory body lines.

“Working with this kit was a challenge,” David admits. “It didn’t come with instructions, so we had to go off of old AMG photos and fit everything manually. But in the end, it was worth it. The car now has that iconic AMG look, and the body lines are spot on.” The result is a Mercedes that looks like it just rolled out of a high-end European tuning shop—complete with a blacked-out front grille, sleek side skirts, and a rear valance that ties everything together. Even the wheels have been carefully selected to maintain the balance between modern upgrades and classic design. David has carefully retained the original fuel filler location to house the electric J1772 charging port, keeping the car’s exterior design unaltered. What’s even more impressive is the custom setup that allows him to toggle between 115V and 220V charging profiles using a manual switch, enabling flexible charging options depending on the available infrastructure.

Upgrading the Heart: The Fellten Battery Pack

Despite the impressive performance of the Tesla motor, David knows that an EV is only as good as its battery performance. While the current Chevy Volt battery setup provides a reasonable range of approximately 80 miles, it’s clear that David is thinking ahead—especially as his plans for the car include longer drives and the addition of electric air conditioning. ‘‘These Volt batteries were easy to work with but required significant time to wire to an aftermarket BMS system. The first BMS system I used never fully functioned correctly and after a while, I updated to the Dilithium BMS. This meant I had to hand wire 96 cells per pack times two packs plus the grounds to six BMS satellites. They are good robust batteries but don’t have a great energy-to-weight ratio and on top of that are 12 years old and have a reduced capacity.” That’s why he recently ordered a new battery pack from Fellten, a leading manufacturer of custom EV battery solutions.

The Fellten FL10UBP55T battery pack system, specifically designed for electric vehicle conversions, will be a game-changer for the 300CD. This compact, T-shaped, 55 kWh pack is built to fit under the hood of classic vehicles, especially those with front independent suspension, and offers approximately 185 miles of range on a full charge, thanks to a satellite, two-module, secondary pack, to be fitted in the back of the vehicle – offering enhanced weight distribution.

The pack is designed for quick recharging, with a CCS DC fast-charging rate of 70 kW, which means David could recharge the Mercedes from 0 to 100% in well under an hour.

“The Fellten battery is exactly what I’ve been looking for,” David explains. “It’s not just about extending the range—it’s about future-proofing the car. With this pack, I’ll be able to add high-voltage electric air conditioning and fast charging, and I’ll have enough capacity to take the car on much longer drives. And I’ll be able to charge anywhere, which is perfect for road trips.”

The Fellten battery pack is designed with state-of-the-art thermal management and safety systems, ensuring seamless integration with David’s existing Tesla drivetrain and dual cooling system. It comes equipped with built-in contactor control, pre-charge, and battery management, along with three 25A auxiliary outputs for systems like HVAC, which will allow David to finally add high-voltage electric air conditioning. The pack’s nominal 350V and peak discharge rate of 330 kW mean it can power the rear drive unit with ease. With the new battery, David will also have the option to incorporate CCS fast charging for quick and efficient recharging or even opt for a NACS charge port upgrade.

About to Ride on Air

But David isn’t done yet. As a car enthusiast and tinkerer, he’s always thinking about the next step in the evolution of his beloved 300CD. One of the most exciting future plans for the car is the addition of air ride suspension, which will give the Mercedes even more versatility. “Right now, the stance is great, but I’d love to have the option to drop it lower when it’s parked. Air ride would let me adjust the suspension on the fly, so I can have a comfortable ride while driving and a show-stopping look when I’m parked. I’ve come a long way with this car, but there’s always something new to do. I love the process of building and improving—it’s part of what makes this car so special to me.”

As more car enthusiasts look for new base cars to bring unique vintage cars into the electric age, David’s build certainly shows how to do it right. His attention to detail and respect for the original design, with a touch of period-correct enhancement, has resulted in a car that’s truly one of a kind.

SPECS

David Rosenstraus’ 1980 Mercedes 300CD Tesla Swap
Make: Mercedes-Benz
Model: 300CD (W123)
Year: 1980
Original Engine: 3.0L inline 5-cylinder diesel
Conversion Type: Tesla Model S electric drivetrain swap

Powertrain

Electric Motor: Tesla Model S rear drive unit
Motor Power Output: 400 horsepower
Torque: Instant torque
Transmission: Tesla direct drive (single-speed)

Battery System

Current Battery: Chevy Volt battery packs
Battery Range (Est.): Approx. 80 miles (185 miles with upgraded battery pack)
Charging Type: J1772 charging port with plans for CCS fast-charging capability
Thermal Management: Dual cooling systems sourced from a Chevy Volt, with separate radiators and cooling fans for the battery and motor

Suspension:

Current Setup: Adjustable coilover suspension, AMG-style lowered stance
Planned Upgrade: Air ride suspension

Brakes

Braking System: Stock Mercedes braking system with a Volvo electric vacuum pump for power brake assistance. Full adjustable regen braking from Tesla motor

Cooling System:

Cooling Reservoir: Dual-chamber Chevy Volt reservoir
Radiators: Two separate radiators (one for the battery system, one for the Tesla drive unit)
Cooling Fans: Electric fans with automatic temperature control
DC-to-DC Converter Cooling: Chevy Volt DC-to-DC converter with a cooling fan for constant operation

Body and Exterior

Body Kit: Custom AMG replica body kit sourced from ClassicEuroParts.com
Bumpers: Euro-style composite bumpers (tucked design)
Color Matching: Paint and bodywork by Boca Paint & Body, perfectly matched to the original Mercedes factory color
Spoiler: Custom-mounted rear spoiler
Wheels: Custom 18-inch rims by St. Paul Speed wheels made by Rotiform (close to its  VCE-T model design)
Tires: 225/40R18 Hankook Optimo H426

Interior and Electronics:

Power Steering: Electric power steering pump (sourced from a Volvo) with a manual toggle switch for on-demand activation
Battery Management System (BMS): Dilithium BMS display unit installed in the dashboard
Pre-charge System: Zeva pre-charge controller connected to original glow plug light repurposed as a Tesla pre-charge indicator
Instrumentation: Custom shunt and ammeter gauge to monitor power draw and regenerative braking

Performance

0-60 Time (Est.): Approx. 4-5 seconds
Top Speed: Limited by Tesla motor configuration (est. 125-140 mph)

Additional Features

Rear Trunk Space: Slight reduction due to battery pack installation but retains practical storage capacity
Weight Distribution: Improved by the placement of the battery packs and motor, resulting in a lower center of gravity