Software is winning (and losing) races in Formula E’s second season

Drivers matter, but so does code


Formula E heads to Argentina this weekend for the fourth race in the all-electric racing series’ second season. Last year, the cars were all essentially the same. But now, the series allows manufacturers to independently develop their own drivetrains. Basically everything behind the battery — the electric motor, the gearbox, and the rear suspension — is fair game.

The result, so far, is sort of predictable. The two teams still running last year’s package are having trouble keeping up, and the team with the most money invested — Renault e.Dams — is by far the strongest. Renault has the lightest car on the track (thanks to the purchase and inclusion of some exotic components) and what appears to be the most efficient drivetrain. Driver Sebastien Buemi has won two of the first three races, and looked strong in the race he didn’t win — right up until he ran into a software problem.

Buemi was leading halfway through the second race in Putrajaya, Malaysia, when his car slowed to a halt. At the same time he stopped on the track, his teammate Nico Prost pulled into the pits with a similar problem. In the blazing heat, it appeared both Renault drivers were struggling with Formula E’s critical balance: using as much of your battery’s energy as possible without causing it to overheat.

Buemi is a finesse driver, so it wasn’t that he pushed his car too hard. Renault’s team principal later confirmed that it was the software that manages the electrical systems that had given out. The team simply didn't factor in the right racing conditions when programming the car. Later in the race, Team Aguri driver Antonio Felix da Costa faced a similar problem. A few laps after that, Buemi’s car stopped again. And one race later, Virgin Racing’s Sam Bird was running fourth when his car shut off.

This is the battle that Dilbagh Gill, the team principal of Mahindra Racing, says is even more important right now than the differences in drivetrains.

“The two most important factors that we look at during a race is thermal management and energy management [of the battery],” Gill tells The Verge. “Last year, many times we finished the race with energy left over in the car which we couldn’t utilize because we had maxed out on temperature.”

Dilbagh Gill in the garage during pre-season testing. Photo courtesy of Mahindra Racing/Current E.

Formula E drivers manage this by lifting off the throttle and coasting into turns, but that only helps so much. A number of things factor into how the battery behaves over the race, all of it mitigated by software. Take, for example, the regenerative brakes on the back wheels. Drivers can use a brake bias dial on the wheel to tell the car how much mechanical or regenerative braking to use. More regenerative braking means more of the car’s momentum can be turned into energy during deceleration that goes back into the battery.

But the more you use the regen brake, the hotter the battery gets. On top of that, the different brakes change the feel of the car. “This is a bit of a challenge, because the car feels different from lap to lap,” Gill says. “Any driver is going to find it uncomfortable to come into a corner and not know exactly how the car will behave.”

This is where the software is most important according to Angus Lyon, who works for the Mahindra team as a consultant on the electronics, software, and drivetrain design. And not just software, but some low-level artificial intelligence systems, too. Yes, while Formula E has an autonomous racing series waiting in the wings, it’s also employing some autonomy in the main series — albeit on a much smaller scale.

The Formula E cars use some low-level AI, but too much can wreck the driver's feel of the car

“It’s certainly not about making the cars drive themselves,” Lyon says. “And it’s interesting because that’s very much where Roborace and Formula E are going to be two different extremes of similar technology.”

Rather, Lyon says, “it’s about allowing the car to make some level of decisions for itself as to what might be the best strategy, what might be the most efficient way of driving.”

This software helps deliver the same power from the driver’s point of view, but finds ways to consume less energy. The team is careful not to go too far with it, though. “A car that’s changing saps driver confidence,” Lyon says. “You may look at a new [software] strategy and say ‘that will gain us one- or two-tenths of a second per lap.’ But if it’s a system that makes the car less consistent to drive, you’ve instantly lost between a half a second to a second just because of driver confidence. So at that point you just park that strategy and move on to the next one.”

What’s even more fascinating about the work that Formula E teams are doing with software is that there are no standard programs issued by the series, or by its governing body, the FIA. It’s all up to the individual teams.

“All the tools are bespoke,” Lyon says. “We have some tools which are quite simple — Excel spreadsheets that will just allow us to quickly analyze data. Some of them are more complex strategic analysis tools where the data from the car will be taken into an application running on a PC, which crunches through the data and is looking at all sorts of things from the car dynamics.”


A Virgin Racing team member plugs into the car's electronic control unit during season one in Miami.

That’s a little easier than it sounds, if only because Formula E cars don’t produce the amount of data that Formula 1 cars do. F1 teams, Lyon says, get live telemetry in the form of hundreds or even thousands of channels coming off the car in real time. Formula E teams get very little live telemetry while the car is on the track — basically just water pressure, voltage, and battery temperature. Unlike Formula 1, Formula E teams have to wait for cars to return to the paddock before plugging right into the “brain” of the car, a series-issued electronic control unit (ECU). There, they download as much as 1.2GB of performance-critical data every race day.

That’s still a lot of data to manage, but Lyon isn’t worried about espionage between teams. He says the team takes “sensible” precautions to make sure the data is safe, particularly where it is transmitted wirelessly. “Luckily the Formula E paddock is a nice one,” Lyon says. “Everyone’s in the same situation, it’s all new, everybody’s learning. It’s not what I’d describe as ‘cutthroat.’”

Mahindra has been in the middle of the pack most of the year, well behind the leaders like Renault. Lyon thinks that the best chance the team has of improving on its finishes is at these crucial race day moments of data download and analysis.

In the end, though, the driver still has the most bearing on what happens during the race. “Since we get very minimal telemetry during the race, it’s up to the driver to sort of make some of these decisions,” Gill says. “And for that we have to go back to my favorite word: simulations.”

Gill says that for every hour of racing, the team is doing 140 hours of simulation. That includes actual seat time in a full-size simulator for the driver, as well as race simulations run on a computer. The driver will run a simulated race, then the team will use that data to simulate dozens of races on a computer, and then they use that data to inform the driver before his next simulated race, and so on. It’s a dizzying process that Gill says is necessary in part because their drivers come from more traditional motorsports backgrounds where you can drive the cars a lot harder.

The Mahindra team performs 140 hours of simulations for every one hour or racing

This is a lot to consider for what amounts to a 45-minute contest, so Gill breaks each contest down into two or three lap segments, and they use strategy software to plan out the race. If the first two laps go according to plan, and the driver is lifting enough to keep the battery charged and cool while still racing hard, the team moves onto the next two laps. If things continue to go well, he might be able to squeeze an extra lap out of the battery, meaning he can drive harder in the second car. (The batteries in Formula E only last about a half a race right now, so the drivers switch cars near the halfway point.) If the driver uses too much energy, or bumps up against the thermal limits of the battery, the team has a contingency plan ready for the next few laps that goes easier on the battery.

But, of course, we’re talking about open wheel racing on tight street circuits. Software can, in the end, only do so much. All this planning, bespoke computer programs, and advanced technology can mean nothing if your car slams into a wall or the suspension breaks. When that happens, “you’ve just got to tear up your original strategy,” Lyon laughs.

Formula E's fourth race of the season takes place Saturday in Buenos Aires, Argentina. Start time is 2:00PM ET. The race can be seen in the United States on Fox Sports 2 at 8:00PM ET. Global broadcast schedules and live streaming are available on the Formula E website.