Ray Magliozzi
Dear Car Talk:
I’ve always loved your radio show (now Car Talk podcast), and even visited your office in Cambridge, Massachusetts, once. You weren’t there. Your staff said you were busy with your second afternoon nap.
Anyway, as a driver, I have always tried to avoid jackrabbit starts to improve my fuel economy. I now drive an electric vehicle and wonder whether the laws of physics apply the same to how you accelerate with electric cars.
Am I saving range by accelerating more slowly? It’s more fun to step on it!
— Chris
It is fun, isn’t it? I have to admit that every electric car I’ve driven, I’ve floored, just for the thrill.
A theoretical physicist would tell you that in an electric vehicle, how quickly you accelerate makes no difference. Whether you take one second or 60 seconds to get up to 60 mph — you’d be using the same number of kW to move the car’s mass. End of story.
But there’s a reason the newspaper doesn’t hire theoretical physicists to answer your car questions. In the real world, there are losses and inefficiencies, even in a battery-electric propulsion system. They’re due primarily to things like heat and resistance.
You can experiment with this yourself, Chris. Top up the battery then drive the same route under the same temperature and weather conditions. On your first pass, do everything gently, and on the next, floor it each time you take off until you get to your traveling speed. Then see how much range you have left when you get home each time. I think you’ll see some difference. Not as much as if you were flooring a gas-powered car because electric motors are much more efficient, but I think you’ll see some loss of range.
Range aside, many of the other reasons why we advise against hard acceleration still stand — even if the car is electric. When you slam your foot on the accelerator, you start a chain reaction of force that stresses every connected part of the car, from the drivetrain right down to the screws that hold the dashboard together.
Now, it’s less injurious in an EV because the electric motor doesn’t care. It’s just magnets spinning on a shaft, rather than pistons and connecting rods flying up and down.
And there’s no transmission in most EVs, so that’s another thing you don’t have to worry about. But you still have axles, a suspension system, and hundreds of body welds that are stressed by hard acceleration.
I don’t want to be a buzzkill, Chris. The acceleration on even the most pedestrian EVs is pretty thrilling. And if that’s what tickles your berries, don’t let me stand in the way. But it’s still not 100% cost-free.
Got a question about cars? Write to Ray in care of King Features, 628 Virginia Drive, Orlando, FL 32803, or email by visiting the Car Talk website at www.cartalk.com.
