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.

A Paris-based startup called 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 told Automotive News Europe .

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 ($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 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.

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.