Range anxiety is one of the biggest concerns for people considering buying a new EV. One of the most popular ways to completely get rid of it is with a hybrid range extender, which theoretically offers the benefits of EV propulsion with the convenience of filling a fuel tank. But can you home brew your own?
The Warped Perception YouTube channel decided to find out, and put a turbo diesel engine into a Tesla Model S P85D to help it complete a 2,500-mile (4,023 km) road trip while charging as little as possible.
While the setup looks pretty sleek, albeit partially external, one problem is immediately clear. Despite a muffler, the diesel engine is extremely loud. If one of the reasons you’re interested in an EV is the quiet luxury, you may not want to plant an engine on the back of your car.
“With that constant droning in the background the entire time, you either forget about it or want to open the door on the freeway and jump out… But it got me to where I needed to go,” he told Insider.
Read: Hybrids Remain The Preferred Electrified Choice For U.S. Car Shoppers
Another problem reveals itself over the course of the drive: cooling. Throughout the trip, the diesel engine is continuously overheating, preventing the roughly 25 hp (19 kW/25.3 PS) generator from charging the batteries as quickly as it possibly could.
Still, despite only ever managing to make the engine operate at 80 percent power (thanks to a massive roof scoop), the car eventually runs at 59 Wh/mile. The builder estimates that would allow the Model S to go 1,600 miles (2,575 km) on a single charge with a full tank of diesel.
Unfortunately, the car wasn’t running at peak efficiency the whole time, which meant that 77 gallons (291 liters) of fuel had to be used during the filming of this video. On the drive, that amounted to fuel efficiency of roughly 35 MPG (6.7 lt/100 km), which is about what a 2023 Honda Civic can manage on its engine alone.
While the Tesla is bigger, heavier, and more powerful than the Civic, it remains a rather disappointing fuel economy figure if you’re ecologically minded. The second iteration of this hybrid Model S concept, Warped Perception says it is now considering using a supercharged rotary engine to charge the batteries, in order to make the car even more efficient and sleek.