Steve Matchett breaks down the complex systems behind all-electric Formula E vehicles

Video Details

Hear Steve Matchett explain exactly what goes into to powering an all-electric Formula E vehicle.

[MUSIC PLAYING] STEVE MATCHETT: Formula E cars are powered by battery-stored electricity. A 90-minute plug-in session is all that's necessary to charge the bulky lithium ion unit from zero to 100% capacity. With the completion of each racing lap, the 20 batteries of the 20 on-track cars begin to discharge their stored energy.

And it is a process of steady decline, around 5% a lap, an unavoidable condition and one meticulously monitored by the teams earnest engineers. And they have every reason to be concerned, too, for should a battery's capacity fall to zero, the car to which it belongs will choke to a thoroughly undignified halt.

And for those of us used to gasoline-powered race cars, a Formula One car, for example, we can think of this as, well, running out of fuel. Now, certainly, the net result is precisely the same-- game over.

To help prevent such a sorry happening, the graphics to the left of the television screen reveal the current state of charge for all cars touring the racetrack. And here, we discover more commonality between the engineering of Formula E and Formula One. For both of these FIA [INAUDIBLE] use kinetic energy recovery systems, known more simply by the acronym KERS.

But when a driver lifts his foot from the accelerator paddle, with or without pressing the brake, the car's control modules have the ability to reverse the direction of electrical energy working through the propulsion system. The freewheeling car, itself, now supplying the rotating kinetic energy back to the powerful motor for its rear wheels, its drive shafts, and transmission.

In this state, the car is recovering kinetic energy. And the electric motor changes its function, becomes a generator, flowing regenerated current back into the battery. If it helps to paint a picture of what's happening here, we can treat this as Formula E's equivalent of mid-race refueling. The KERS regeneration system is topping up the battery, increasing its power, and helping to extend the distance a car can cover before needing to pit.