Driving technique? How much does a lead foot cost?

[plj]

How much does driving technique affect range (or miles per kWh)? Does hard acceleration hurt?

Physics says the energy used is just the change in velocity (KE=mv^2). But does the battery lose efficiency when we place large instantaneous demands for power, versus smaller, but longer duration power demands?

For some of us, an interesting part of the shift from ICE to EV is trying to understand the most efficient way to drive. 'Tis simpler when not factoring in the effect of a throttle butterfly, but I feel ignorant when trying to figure out the impact of the speed of acceleration on overall energy consumption. Does, say, accelerating from standstill to 50 mph over 5 seconds and then holding a steady speed for 25 seconds, use more energy than going 0-50 in 30 seconds? That ol' ingrained 'for economy, avoid jackrabbit starts', though I remember the Saab 9000 owner's manual saying for best economy in acceleration: use lots of throttle, short shift, and skip even-numbered gears until you get to cruising speed.

Maybe i'm just looking for justification to enjoy the sprightly acceleration, especially without a shift lever to keep me entertained...

 

[boltage]

A lead foot on the brake pedal will require braking beyond what the regenerative braking can do, forfeiting the opportunity to put some of the energy back into the battery.

Avoiding situations where a lead foot on the brake pedal is necessary reduces energy consumption and improves safety.

 

[LeftieBiker]

Hard acceleration will cost more energy if only because of efficiency-related losses. More heat is generated when the motor and controller are working at the higher end of their rated power. That energy gets radiated instead of propelling the car. Accelerating hard while carrying a passenger or other extra weight will of course increase those extra losses. Also, when you accelerate hard to X MPH and then maintain that speed you arrive at your destination earlier than if you had accelerated slowly to the same speed and then maintained it - you are trading power for a slightly shorter trip, at least in part because you are spending longer at the maximum speed driven, with its higher air resistance. There are also other factors like mechanical and tire friction, which aren't huge but add up, along with the other speed-related factors.

 

[user 1485]

How you drive certainly can affect efficiency, but so can heater use in the winter, and to a lesser extent a/c use in the summer. None of this is important, just like driving on eggs is not important in a gasoline car. Its just a matter of the range between charges, which is brilliantly predicted by the car, so all you have to do is plan accordingly. With my long distance driving in summer, using 238 miles of predicted range for all planning, I was comfortable with a 30-60 miles margin of range left between charges. I suspect if you drive with a heavy foot using lots of cabin conditioning the car will tell you the range left for your style of driving and you can charge more often to account for it. There are lots of ways to look at these situations, but the "range left" and "miles left to the next charger" are all you really need to think about when driving. The car does such a good job with the range left number that its highly unlikely you end up with a disastrous miscalculation, no matter how hard you drive. Now, an electric car is so economical, do the actual lead-foot $$ really matter?