acmotor wrote: Perhaps peak power needs to be something like 10 times average in a vehicle. So peak power needs to be 10 times the cruise at 100kmph power. That leaves 7.5kW motor out ? 10 to 15 kW seems more likely.

In an extreme sports high power vehicle perhaps; say 15 kW @ 100 km/h and 150 kW @ peak acceleration.

For a Barina class vehicle, it's more like 3:1; 16.5 kW @ 100 km/h and 50 kW to match the ICE acceleration. Conveniently, 3:1 is about the Tmax/Tnom ratio for induction motors. So if you size the motor for continuous power, it'll be about right for peak power. That's ignoring overvoltaging.

With overvoltaging, to take account of the higher iron losses, some derating is presumably needed of the continuous power. So that makes the ratio between maximum and continuous power higher, so the continuous power becomes more critical for a low performance vehicle.

For a high performance vehicle, you want a higher ratio anyway, so the peak power may be more important, depending on the ratio you want and the derating that is necessary.

With a 4x overvoltaging, if the new continuous power is 2.6 times the nominal, then a 7.5 kW cont / 25 kW peak becomes 19.5 kW continuous and 100 kW peak, enough for a quite sporty car. But while a non-overvoltaged 22 kW motor might be able to do a 1 minute burst of 100 kW with 4 minute rests (total guess), the overvoltaged 7.5 kW motor might need 5 or 8 minute rests between such burts, since the power ratio is a little higher for it (5.1:1 vs 4.5:1 peak verses continuous).

I think a lot of this will have to come from experience. Unfortunatley, I've decided I don't have the time and space at present to convert White Suzi; I'll have to get my electric kilometers hauling an Atkins cycle ICE around with me. So someone else will likely find out what the limits are.