Customers who want to buy an electric car face the dilemma of either paying more to have a big battery pack and a long range or being forced to charge up their EVs more often.
Paris-based start-up EP Tender believes it has eliminated the need to choose between cost and range. It's plan? Battery trailers.
"We are solving the issue of making EVs which are affordable convenient on long distances," CEO Jean-Baptiste Segard said.
EP Tender is named after small tender boats that service big ships. The company wants to locate compounds of rentable trailers on major holiday routes. EV drivers will pull up, wait for the trailer to autonomously hook to the back of the car, and then benefit from an extra 60 kilowatt-hours of battery power to take them to their destination or the next trailer compound.
The maximum rental cost would be 34 euros ($37) for one trailer, the company predicts.
EP Tender's initial idea was to put a combustion engine in the trailer to create hybrids out of electric cars and the company currently has 20 such trailers in use with customers, all of whom drive Renault Zoes or electric Kangoo vans. But the falling cost of batteries persuaded the company to make the switch.
"The combustion engine version is still used by our clients, but we are not developing it as we have a lot more traction on the battery tender. Batteries have progressed a lot," Hugo Basset, the team's data science and simulation engineer, told Automotive News Europe at the recent MOVE2020 mobility show in London.
Basset said the company is in talks with Renault and PSA Group in France to factory fit the tow bar and connectors to their EVs.
Right now, many EVs are not homologated for towing, but EP Tender says that will change from 2022. Until then it can retrofit a towbar and connectors for 600 euros.
Renault was an early pioneer in the quest to solve the problem of long-distance charging when it collaborated with Israel's Better Place in 2008 to introduce swappable batteries into its EVs, starting with the Fluence sedan.
The gamble failed however, and Better Place was dissolved in 2013.
A trailer carries far fewer risks, Basset argued "We're not spending millions on battery swap stations, for one thing," he said.
The company is working through potential downsides. The trailers for example are being redesigned so the aerodynamic penalty is minimal. The trailers also incorporate a second set of smaller wheels that drop down to make reversing easier.
There is another advantage. When not in use, the trailers can be linked to the grid to return energy at peak times.
The target cost for a trailer is 10,000 euros, and the company's business plan predicts it turning its first profit in 2024 with 60,000 customers renting 4,150 trailers.
In the still fluid world of EVs, range-extending trailers could be part of the armory that helps smooth the path from combustion engine to a more expensive electric vehicle.
It might look ungainly, but the upsides could more than compensate.