The Rapide sedan is Aston Martin's oldest car, but the brand's future might just rest on its wheels. Aston Martin plans to convert the Rapide to a limited-edition electric vehicle to learn how to deliver EVs to customers addicted to its trademark gasoline growl.

"It's not just a car. It's about Aston Martin as a box. Here is electrification — go put that inside a company that has a great history of making V-12 and V-8 engines," John Caress, vehicle line director for the Rapide E, told Automotive News.

Aston Martin plans to revive its Lagonda badge in 2021 as a standalone, ultraluxury electric brand, previewed in March by a limousine concept at the Geneva auto show. "We had people throwing money at us as deposits," CEO Andy Palmer said after the event.

But that's not the hard part. The Rapide E is essentially a prototype for Aston Martin's ability to deliver its Geneva promise.

The battery pack uses the same 18650 cylindrical lithium ion cells used by Tesla, but don't read anything into that.

They were chosen because they're small enough individually to let Aston Martin package 5,600 of them into the same dumbbell-shaped space vacated by the Rapide's V-12 engine, gearbox and driveline.

"We can get as much energy as possible without getting into a massive crash-test program," Caress said. He wouldn't name the cell maker.

The pack, developed by Williams Advanced Engineering, the customer division of the Formula One racing team, even fits into the chassis on the production line the same way as the V-12 drivetrain.

At 65-kilowatt-hours, the Rapide E's battery capacity when it goes on sale at the end of next year will be much lower than that of, say, the Audi e-tron at 96 kWh or the Jaguar I-Pace with 90 kWh. That affects its range, estimated at 200 miles.

On the other hand, it will have an 800-volt charging system, of which so far only the upcoming Porsche Taycan can boast. "If we want to sell the first luxury EV, we have to have something different," Caress said.

The advantage is fast charging (up to 80 percent in 30 minutes) and no "de-rating," or power restricting to avoid overheating. Aston Martin also promises the equivalent of 602 hp and a 0-to-60 mph sprint in less than 4 seconds — helped by its comparatively light battery pack, although no overall weight has been given.

The team seeks to eliminate unwanted noise that had been masked by the V-12, in part by using noise-canceling Pirelli tires.

Electric noises are a no-no. "Electric machines have a certain frequency, but it's very hard to tune them. You get into augmented noises and that's not what this car is about," Caress said.

Aston Martin is looking for input from buyers so the company is encouraging dealership visits instead of over-the-air updates. "If there is an update, we want to talk to you about it," Caress said.

The car will retail for around 200,000 pounds ($265,000) Palmer has said. Aston Martin's goal is to make a small profit with the Rapide E, but that's not the driving force. Said Caress: "It's not just about delivering a car with a business case. It's about delivering electrification into Aston Martin."

Aston plans to build 155 versions of the Rapide E when it opens a new factory in St. Athan, near Cardiff in Wales, next year.