A little-known technical alteration to the management of power and energy in Formula E this season is adding to the complexity of how teams and drivers will run races as a whole.
Formula E Notebook can exclusively reveal that a new rolling four-minute average power implementation could affect drivers races this season and effectively see derating scenarios for those that have not perfected their average power strategy in races via software shared by battery supplier Fortescue Zero. This will include the drivers and teams having to adhere to the suppliers (Fortescue Zero) user manual for each race.
The new process has been introduced to help the duty cycles of the spec batteries that are provided and serviced by the Fortescue Zero company.
Nissan Formula E team director Dorian Boisdron told FEN that the new challenge is in addition to Fortescue Zero “playing with the (RESS) parameter, but (the rolling average) comes on top (too).
“Basically, how it works, it’s like the battery is calculating live a rolling average of power delivered to the rear axle only,” added Boisdron.
“If that power over four minutes is above a certain limit, the battery starts to degrade, so it reduces the power delivered to the rear axle. So, it’s just a question of an extra protection for the battery.
“That can be an extra constraint in typical situations, such as Attack Mode, during Free Practice also, if you want to, or when we did the test, for example, in Madrid, if you are doing too many 350 kW push laps in a row, you can end up in a situation where the battery starts to degrade.
“The threshold is quite high, it’s decently high, so most of the time it’s transparent, but this is something we must manage on top of everything else from a team perspective.”
“The championship is moving more towards that rather than dishing out penalties,” confirmed DS Penske’s tech chief, Phil Charles.
“They (FIA) are saying, ‘we don’t really want to be dishing out penalties afterwards, we want the systems to look after themselves.’
“So, we’d rather not put a straight line and say you need to observe the straight line. They’d rather have the (average) system, the battery cut you at that point, that’s what this does.”
Charles described the management of the average power being discharged as “you push like crazy for four minutes and you’ll effectively get a derate. And it’s not just performance because it’s a rolling average. It depends on how you’ve built up to that push barrier.”
“The driver may have to do something, but the real trick to it is to build software into your car that says, ‘oh, hang on, you’re building up’ and ‘we’re starting to climb up to this derate, so it (the software)gives you a warning.
The FIA confirmed to FEN the framework for the measures, with its Formula E technical manager Vincent Gaillardot saying that “I think as you know we have a car with a certain specification and obviously going to Gen3 Evo we have improved performance, we have improved everything.”
“So, all together we have to take care to stay within our (battery) duty cycle. It’s true for the battery, it’s true for the FPK, it’s true for everything. To protect itself we put in place, like we have already some thermal derating for cell temperature or for FPK temperature, we put in place a rolling average of the power which means on a race if you have a normal race scenario it will never happen.
“Obviously, what we have learned as well from the two last years is this peloton (pack racing) effect races and the fact you finish flat out and the risk with this car is to finish flat out with high performance and this could create some drama.
“To keep equity versus everybody we put in place this rolling average measurement.”
Driver Reaction on Rolling Average
Drivers have confessed to FEN that they see the new procedures as being potential instrumental in latter stages of some races this season.
“You generally lose power, and you will lose positions (if the average is gone over), Envision’s Robin Frijns told FEN.
“The problem with that is, if you are in the pack, meaning P10 to P15, the slipstream is huge with these cars.
“So, you can regen a lot more and if you have a good car, and you have a bad qualifying, and you start P10-P15, what you’re doing is you’re regenning a lot, which causes this number to go up, and you are in a spiral going down all the time, because you can’t move forward.
“Then it’s difficult to overtake properly. You’re using more energy, you’re getting more energy in the battery, and this (average) number is going up and at one point, you’re dead.
“So, it’s more important, I believe, to be somewhere in the top eight and to not have this potential issue.”
Jaguar TCS Racing’s Mitch Evans broadly agreed with Frijns, saying that “going over the rolling four minutes you will get the power derate.”
“We’ve not really experienced that yet, or how severe that could be,” added the Kiwi.
“And obviously, when the target goes up at the end of the race, you’re more at risk of getting that (derate) especially when you’re on attack mode. So, the attack mode is going to be more usable, but you’ll have to be smart with how you use that, with managing all these new variables, new curveballs that we’ve got to deal with.
“On top of that, you have battery temperature to consider this weekend and it should be pretty hot. There is a lot for us to manage, which was already a lot beforehand anyway.”
