Hey there,
I recently acquired my first EV and have been having fun trying to get the best efficiency numbers out of it. I was at ~3.5mi/kWh (5.6km/kWh), but by slowing down and taking the other road not the highway to work I got it up to 4.4mi/kWh (7.08km/kWh). Part of that was accelerating relatively slowly as this is one tip that I heard. But I’ve been thinking about it and from a simple physics calculation it should take basically the same amount of energy to accelerate an object to highway speed whether you do it very quickly or if you spread that energy over a longer period of time.
Does anyone have any insight? I don’t mind granny accelerating but if I can have the zippy fun of accelerating an EV while still staying efficient that would be awesome too :)
Thanks!
Your physics instinct is right in a vacuum.
Same speed should be the same kinetic energy.
But the real world adds losses, and those punish hard acceleration:
Electrical losses scale roughly with current², so flooring it wastes more as heat
Motor/inverter efficiency drops at very high power
Tires waste more energy under high torque (slip)
Drag starts biting earlier if you hit high speeds sooner (ever ride a bicycle?)
Moderate, steady acceleration is most efficient. Not crawling, not flooring it. Use ~30–60% pedal (middle way). Smooth, continuous push.
You can still have quick launches occasionally without wrecking your efficiency. Just don’t make it your default mode.
Pushing the batteries and motors harder results in more waste heat. So the harder you accelerate, the less useful energy you get, i.e. lower range.
Not to mention the tire wear
Does it or is it the same heat over a shorter period of time?
This graph shows 40C is optimal. So accelerating harder on a cold day could improve range.
Better to pre condition the battery before driving then, while plugged in.
but that uses energy you should account for, even if you don’t see it in your EV dash.
In cold conditions using the battery to heat itself is more efficient than not.
Sure, and I can see that being a difference between accelerating very slowly vs flooring it and flooding the motor with 150kw. But I still wonder if it’s significant between holding 20-25kw for several seconds vs 50-60kw for only a couple seconds.
The efficiency peaks in the middle.
In electrical terms you’d be pulling more power from the batteries and over any cables, P=I^2R which would technically result in more losses in the conductor at higher currents. Also depends on the efficiency of the batteries and motor.
I can only speak anecdotally, but the anecdote comes from years of driving an ev. When I’m driving, the first ~8 miles I have to drive to get anywhere involves a long sequence of stop and go lights. I’ve experimented with both aggressive and very conservative acceleration in this, and what I’ve found, is that it really, really doesn’t matter.
Its practically the same. My thinking is basically that energy = energy. As long as I’m not overshooting the target speed, the rate of acceleration isn’t relevant. It takes the same amount of energy either way (in terms of observed, battery based kwh). Basically, if your target speed is the same, it doesn’t matter if you are getting to that target speed faster or slower. It takes the same kwh to get the big lump of mass from rest to that speed.
Now where I do find efficiencies is in what that target speed is. Even a bit of traffic massively increases my battery efficiency.
The bigger impact is shedding that speed I think. If you jackrabbit then brake for the next light, it’ll kill the battery even with regen.
absolutely. ideally you don’t use any brake whatsoever. breaking is absolutely the enemy of efficiency.
and jackrabbiting works if it allows you to stay in rhythm with the green lights not having to use the brakes. but you should imagine braking as basically “throwing away” energy, even with regen.
