It's not the speed of the EVs that is the problem. It's the range and charge speed. Formula 1 and NASCAR include multiple pit stops in a typical race. Formula 1 pit stops are between 2 and 3 seconds. NASCAR stops are between 9 and 12 seconds. You can't recharge batteries fast enough.
And range. Formula E races are between 60 and 100km. 1/3 of the F1 ICE/hybrid race distances.
A road EV, which may have a
cruising range of 400km+, would probably have that range sharply compromised if it was driven
flat out for the 45mins of a Formula E race.
Cruising the highway, I can get less than 6litres/100km out of my current Subaru XV(Crosstrek) and expect 4.5 from the RAV4 hybrid we're about to take possession of, but put the foot down and you can guarantee that that fuel consumption will be doubled.
It would certainly sap the battery in a road EV in
race mode. It would not surprise me if it emptied the battery before completion of a Formula E race as their batteries aren't built for rapid discharger. Even when designed to, initially in FE, the drivers had to swap cars 1/2 way through a race and jump into a different, fully charged car, to complete race distance.
There is currently a pit-stop recharge option - but it will cost you a minimum 30 second stop.
They have come a long way, but road EV cars (and especially batteries) were not meant to discharge under race performance conditions.
In fact,
this article comparing an Audi EV to an Audi V8 claims that,
... the GT was chewing through 30 to 40km of range per lap, and Phillip Island is only 4.5km long. This gives you a useful track time of optimistically 12 laps before you need to recharge...
The BYD mentioned upthread probably has a battery designed to cope with fast discharge, but even then it is not designed for constant high speed discharge and it's advertised range is estimated from controlled cruise-speed, not sustained track racing speeds.
