Originally Posted By: JHZR2
Originally Posted By: Cujet
Also, cars such as the Tesla can be accelerated hard without any range penalty. The "work" done is the same, whether done slowly or rapidly. Because the Tesla uses elec power, there are no engine efficiency problems with high rates of acceleration. The Prius could stand to have more powerful electric motors to provide a better rate of acceleration.
Hogwash. Losses (heat) increases as the square of current. So if we're talking a 270V system, 270kW is 1000A. Given the mass and speed, I'm assuming that the car puts out something around there. So the losses are one hundred times higher than if it lightly accelerated and cruised, pulling 30kW.
Math is 270kW = 1000A X 270V and 27 kW = 100A X 270V, while I^2R losses mean that for constant R, the power dissipated as thermal losses is 100x higher at 270kW 1000^2=1000000 while 100^2=10000; 1000000/10000=100.
There is no question that resistive heat losses and battery heat losses at a 4C discharge rate are increased. We can even include the tire distortion frictional losses too. It matters not. The real world results are in. Rapid acceleration in battery powered vehicles does not appreciably affect range. The work done is the same and the energy consumed is, in effect, not significantly different.
There is also no question that the various drag forces are not independent of speed. I clearly understand this. So, rapidly getting to "Cruise speed" results in more time at the "high drag" velocity. Once again, it matters not, when the "cruise speed is fairly low, such as in a 30, 35 or even a 45 or 50 MPH zone. The increased time at the high drag speed is not enough to reduce range appreciably. This changes when out of the city and speeds increase markedly. I am unaware of any "stop n go" 70MPH zones.
Real world testing results from Tesla: Going flat out 0-60 mph uses less than 0.1 kWh of energy from your battery MORE than going very slowly 0-60 mph.