This French start-up can convert your car into a hybrid EV in a day

A French company is working on a new retrofit kit that can convert your old vehicle into a hybrid electric one in just a day. 

Workers with Solution F, a subsidiary automotive company of Green Corp Konnection (GCK), a group of companies who say they are leading the French green energy transition, displayed their project at the Paris Motor Show last week. 

The Twin-E kit allows cars to run up to 50 km/h in “full electric mode” then switches to a hybrid power if it goes over that speed.

To do this, the company installs a 48V electric engine along with a planetary gearset, which replaces the car’s old manual gearbox. Then, a rechargeable battery is added to the floor in the boot of the car. 

A small electric motor is also installed next to the original internal combustion engine (ICE), which uses battery power to run the car when in full electric mode. 

‘A complimentary offer’ to new EVs

The French government defines retrofitting a car as converting its thermal engine, either petrol or diesel, into an electric one to give it a second life.  

“[Retrofitting]… constitutes a complementary offer to new electric vehicles, the purchase price of which still remains high for a large part of the population,” the French government wrote on its website. 

The Twin-E kit is not available yet, but GCK program director Eric Planchais said it should be ready by mid-2025 and it should cost roughly €8,500, or €4,000 if covered by a French government subsidy.

The average price of an electric vehicle in Europe sat at just under €46,000, according to the European Alternative Fuels Observatory. 

France legalised these electric retrofits in April 2020, starting a race between GCK and other European companies to meet the market.

Renault Group, one of France’s biggest auto manufacturers, announced a partnership with Tolv, a retrofitting expert in France, to convert over a thousand Renault Master vans in 2024 and 2025. 

Rev Mobilities, another start-up in Paris, reequips vintage cars like a 1957 Fiat 500 with electric parts.  

‘You’d really have to do the math’

The retrofit splurge is also happening in the wake of EU legislation passed in 2023 that is looking to make electric vehicles account for about 80 percent of all new sedan and SUV sales by 2030, and 100 percent by 2035 to meet climate targets. 

Not all automotive experts are convinced that retrofitting is the solution to meet the EU’s goals. 

For Patrick Poincelet, president of recycling company Mobilans, retrofitting is a “niche” solution for some vehicles, but not all of them. 

ADVERTISEMENT

That’s because the cost of the retrofit sometimes outpaces the value of the older car as it approaches the end of its average 20-year lifespan, Poincelet said.

“To get an economic balance, you’d really have to do the maths,” he added. 

Cléa Martinent, director of sustainable development with Renault, said her company is supporting start-ups working on the retrofit question but that the economic model isn’t quite there yet. 

“We can say, a bit naively, that changing a motor means that it’ll be all good, but in reality, if you really want to retrofit a vehicle, we’d have to dedicate alot of time to it,” Martinent said. 

ADVERTISEMENT

That’s because, she continued, you’d have to change the entire layout of the car, because “you can’t put a battery where there used to be a motor”. 

Expansion planned in other markets

Back at the Paris Motor Show, Planchais said they built the Twin-E kit with a Renault 1.5 engine in mind, which he says is the most common one used in French cars. It also can fit with Stellantis cars, so anything produced by Peugeot or Citroen. 

The kit can be used with most older French vehicles, dating back to roughly 2006. 

Planchais said during their regulation testing, they are looking to see whether the kit would work on other models outside of France. 

ADVERTISEMENT

“We plan to check it but normally it’s okay,” he said. “We plan to go in Africa, in India, in Asia, why not? It’s all possible”.