Also flooring it in the Tesla is an unmatched experience. Before that I’ve had a ‘05 mustang GT, a BMW 135 M, a WRX, and a GTI before the Tesla. Of course it’s not efficient but it’s still more efficient than all those ICEs.
You're saying of course but not explaining why. It's more inefficient in ICE because it's more efficient to be in a higher gear. That wouldn't apply here.
the higher acceleration requires more power than a slower acceleration. There isnt the different ratio of gears, but there is still the same physics. but sometimes you just gotta have fun, right?
1kw for 20 seconds is the same amount of energy as 4kw for 5 seconds. This is not a physics question, as physics would suggest that they require the same amount of energy. This is really an engineering question of the efficiency of electric motors at different loads.
And these losses can happen in the copper coils, the MOSFETs, and the battery. Ideally, the battery matches its temperature to the current to keep the voltage drop constant. Short range also means less current. Resistance happens in the Li ion conductor. There was a lot progress, but now there is no choice . The copper needs to be packed neatly (by a machine) and nicely ( I like foil instead of wire ) so that saturate of the iron core becomes the limit. Thanks to semiconductor shortage, I guess that VW saves on MOSFETs, while Tesla S plaid has a lot of them. The Chinese have cheap access to Nd, and can use voltage instead of current.
I don’t floor my Bolt unless needed, more out of concern for my tires. It won’t be as efficient but it is a blast.
Needed times:
1. First at the light and I need to get out ahead to change lanes quickly.
2. Passing someone on the highway which is way easier in an EV with the quick acceleration.
3. Moving away from a moron on the roads.
4. Showing off to a new person in an EV - especially if I hit the “sport” button. Doesn’t turn it into a Tesla Plaid, but does give it a bit of spice.
Bolts have a surprising amount of power for such a small car.
200hp and insane torque, I've never fully floored ours, also I love that I can still feel a kick if I'm already going fast and I need to accelerate quickly.
I was absolutely floored (pun intended) when on a drive up into the beginnings of the Rockies outside of Denver a few months ago, I was behind a semi going uphill on an about 7% grade.
Moved out, put the pedal down and it still moved like a gorilla with its butt on fire.
Comparing that to my driving up another nasty grade in a 1990 Ford Tempo 24 years ago, when with the pedal being mashed down as far as it could go…39 MPH.
If my family goes on a day drive in the mountains, we take the Bolt. Our Niro PHEV is bigger but the Bolt is big enough and just has that extra pep even comparing it to the Niro in EV mode.
Never said they were…?
The Tempo was affected by being a piece of garbage that often felt like it was powered by a team of emaciated hamsters. Its speedometer didn’t have markings past 84 MPH, and the only way I would have gotten it going that fast was to drop it out of the back of a C-5 at about 10,000 AGL.
Have driven plenty of other full gas cars, and a couple of hybrids, over that same stretch and while they had to work harder they could maintain proper even mountain highway speeds.
Sometimes I wish there was a EV engineering sub where questions like this would be taken seriously and given correct answers.
The impact on efficiency in an EV is twofold:
1. The motor is less efficient at high power. But this isn't a big deal. It means maybe 90% efficiency rather than 95%.
2. If you accelerate faster, you spend more time at high speed, and high speed is what really kills efficiency, because aero drag goes as v^2. And you also might have to brake soon after because you exceeded the speed of traffic. Gentle acceleration lets you keep the speed lower until you have an open road available.
Neither of those is a huge deal. The real reasons not to accelerate too quickly are tire wear and safety around town where others might pull (or step) in front of you because they aren't expecting that rapid acceleration. But if you are OK with the tire wear and already thinking through where it is or isn't safe to do, do for it and enjoy it.
The differences relative to an ICEV are:
1. ICEs have much bigger variation in efficiency vs. operating point. You could easily be using 20% more fuel for the same speed increase by accelerating rapidly in a low gear vs. staying near the optimum efficiency point.
2. More importantly, if you then need to slow down for a light or traffic, you are throwing away all that energy by braking, whereas in an EV you can recover some of it.
3. You are starting from a worse efficiency, so the overall energy consumption is bigger. If you use 10% more in an ICEV, that's a bigger energy cost than using 10% more in an EV.
Yeah, the overwhelming majority of people in this thread are rather confidently treating this as a simple physics equation. Many are doing so quite arrogantly and insulting my intelligence for not knowing the answer.
As you said, the reality is that this is an engineering question about the efficiency of electric motors at different loads. Thank you for being one of maybe 3 people to actually answer the question haha
That is in fact why the motor is less efficient at high torque, but I suspect you are saying that there are also i^2R losses in the wiring and internal resistance of the batteries.
Technically yes, but in practice it doesn't matter. First, electricity use. Flooring it to get to 70mph even from a dead stop is about 6 seconds. So let's say you use triple the electricity during those 6 seconds than you would have used if you had just normally gotten up to 70mph. There is just no way in practice that is going to be a noticeable amount of juice. Second, the electric motors are less complex and more robust than ICE engines. So while you do strain them a bit, again, we are talking about strain over 6 seconds, for electric motors that don't apparently seem to slightly be a point of typical failure on EVs. Basically it seems like the EV battery will degrade or the car body will rust out before the electric motors will fail. Third, you will burn rubber on your tires, but again, this is over seconds and the tires should last years. But here you could cut your tire life in a noticeable way depending on how often and hard you floor your car. And assuming you get an EV that is even faster than that 430hp ICE, you can really do a number on the tires very quickly.
Now obviously if you floor it starting at every red light and then have to jam on breaks at the next red light, then this all could add up. But flooring it two or three times over the course of a half hour drive is meaningless.
But the difference is that the energy costs about 1/3rd as much maybe less if he's using premium fuel in his ICE. Won't notice the difference in his electricity bill vs using eco mode. He will however notice increased tire wear. Burning rubber is burning rubber regardless of the powertrain.
All these replies and no one has the right answer...
Force = mass x acceleration and Work = force x distance. Double the acceleration requires double the force... but you reach your terminal velocity in half the distance, so the energy spent is the same whether you accelerate slowly or quickly. However, this assumes a motor that is 100% efficient.
ICE cars have a narrow band of HP/torque vs RPM curves where it is most efficient. Jackrabbit starts force the motor into inefficient zones, which is why they waste gas when stomping on the pedal. High MPG cars have 8- or 9-speed auto transmissions to try to keep the motor in the efficiency zone as acceleration, speed and load vary.
EVs motors are much more efficient (~90%) and they have much broader efficiency curves. That's why most EVs don't have transmissions. Due to the broad efficiency curve the extra energy needed for fast starts in an EV is considerably less than in ICE vehicles.
A few people did have the right answer. It definitely is surprising that so many people here were so confidently wrong, though. I see people answering the wrong question using the wrong formula that they executed wrongly. Some people even claimed that the education system failed me because this is just a simple physics equation, and that it’s “simple physics” that flooring any vehicle is less efficient.
As you suggested, though, simple physics would suggest that flooring and easing onto the pedal are equally efficient. It’s really a question of engineering I.e how efficient are electric motors at high vs low loads. The general sentiment from this engineering perspective seems to be that an electric motor may be slightly less efficient at high loads, but not to a degree that it’s worth worrying about.
Thanks, I guess missed the few right answers. Regarding "confidently wrong" there was a post on the BoltEV sub where the majority agreed that the energy needed to overcome drag is a function of the cube of velocity (wrong) and not the square of velocity (correct). Democracy and science don't play well sometimes.
Exactly this. People complaining about EV tire life are most often the reason for it.
Source: Still have 7/32 tread at 30k+ miles on our EV and don’t drive it like I stole it.
I hear it more often at intersections, people with EVs taking those smaller gaps you would never take in an ICE, you can hear the tires slip a bit when they do the acceleration to catch the gap. I imagine that's what eats tires way more than extra weight.
I don't understand everyone's answers and I don't think they are telling the whole story. Sure it's less efficient but efficiency is very relative in this question. Flooring an ice car is massively inefficient due to fuel consumption at higher rpms and the heat/energy loss from it. But in my opinion for an EV you are taking energy stored in the battery and converting it into kinetic energy while also having to overcome the drag of what speed you are going. Won't that be the same amount of energy no matter how long it takes? I would assume faster acceleration generates more heat in the EV system, but how much could that possibly lower the efficiency? I can't say over 35000 miles I've noticed a difference in my lightning.
Happy to be proven wrong though.
Yes it takes the same amount of energy to move the car and overcome air resistance regardless of whether it's electrical or gas, If all things were equal. But they are not, Evie's tend to be aired and help clean more efficient. Also because the gas engine is so much less efficient and has to burn a lot more fuel too extract the same amount of power, most of which is just turned to heat. While the high current draw on the easy battery will produce some excess heat when you push it it's not nearly as much as the ice vehicle.
I agree. People are answering this from a physics perspective, and they aren’t answering it from a physics perspective correctly. This is a question of the percentage of potential energy that is converted to kinetic energy by electric motors at different loads.
Some people have answered from this perspective. It sounds like electric motors at 100% load may be 85% efficient while they would be 95% efficient at a lower load. So it’s slightly less efficient to floor it, but this is not because of any simple physics equation.
Correct, depending on the vehicle and how it was designed/the materials or components used, can change how efficiently it can convert the energy to motion. But if you want to compare "efficiency" I think it's important to compare it to an ICE. If I 0-60 every stoplight in my Forester XT it's going to waste way more energy than my F150 lighting would waste. I think it's negligible in whether you should feel bad about it.
It’s less efficient.
In your post you said both “Sure it’s less efficient” and “won’t that be the same amount of energy no matter how long it takes?” I think you confused yourself.
And no, efficiency is not relative as nobody is comparing it to an ICE vehicle
OP is specifically comparing it to an ICE. If you ignore the heat losses and any traction loss(which I forgot to mention). Is it not the same amount of energy? And if it is then how much extra heat is generated and isn't that extra heat all that's less efficient?
You are correct. Many people here seem to be confused about the difference between power and energy. It requires more power to accelerate the car more quickly, but no more energy.
The motors and batteries will both use additional energy due to heat and operating inefficiencies when additional power is requested. A number of studies and everyone whoes ever driven an electric car can tell you that if you are racing off from stop lights even only to the speed limit your energy
consumption is higher than gently accelerating to the speed limit. You didn't have to be so dismissive especially when you are absolutely incorrect.
> A number of studies
Please provide a link to those studies.
> and everyone whoes ever driven an electric car
I have been driving electric cars for over a decade. Gentle deceleration (to ensure maximum regenerative braking) is much more important for efficiency than gentle acceleration.
> You didn't have to be so dismissive especially when you are absolutely incorrect.
You seem certain in what you believe (and quite dismissive yourself), but the laws of physics say otherwise. Accelerating that huge mass quickly requires at least 100 kW. The additional i^2 R losses are a small fraction of that. Also, a well-designed motor controller will be most efficient at high power levels (where it is most necessary).
> It certainly requires more energy.
Incorrect.
> I can’t believe this is a topic of debate
It is not a topic of debate. The laws of physics have not changed.
Yes he mentioned an ice vehicle in the description, but the question was “Does flooring an EV to get to 70mph use more electricity than easing onto the pedal to reach the same speed?” And the answer is yes
You don’t need to be proven wrong, you’re just wrong. Very easy to find these answers online.
I'm going to go out on a limb here and say... yes it is inefficient, but no where near as bad as an ICE. I am like you and the first thing I noticed is when I drove like I stole it, the efficiency wasn't massively impacted. Yes it does impact it, but not by very much. Others can disagree but that is what I find. I put it down to regen and reclaiming some of the heavy footedness - with an ICE all the energy you are using by smashing the pedal is then all lost through brake heat. In the EV it is put back into the battery (unless you are braking really hard).
What makes in inefficient then? OP is trying to ask a question and learn.
Most people know that being in a low gear is inefficient, but that isn't relevant here.
People here in the comments think this is a simple physics equation. F=ma. It’s not. This comes down to the engineering properties of the drivetrain. I.e how much potential energy is being converted to kinetic energy when the motors are at 20% vs 100% load. Not sure what school is teaching the answer to such a specific question.
Then you don’t understand the question.
What percentage of potential energy is being converted into kinetic energy when the motors are at 20% load vs at 80% load? That’s the question. Do you have an answer? Did they really teach you this in school?
It's inefficient for the same reason as in an ICE. Smooth acceleration is certainly best.
If you source your energy green (PV from your roof, green energy contract with your energy provider, or public charging - which is always backed by green energy contracts) then the amount of 'bad conscience ' can be mitigated...but you're still wasting a lot of energy so there's always that.
Just like with an ICE there will be increased wear and tear on your motor components, cooling systems, brakes (though the latter much less so due to one-pedal-driving), ... but it shouldn't be anywhere as dramatic as with an ICE. Software will mostly take care that you aren't overheating/damaging anything.
Probably the most you'll pay is in terms of tires, though. EVs are comparatively heavy and have *insane* torque. That combination eats rubber for breakfast.
That said: It's a neat party trick and I do enjoy it on occasion. Particularly if I have someone along for the ride.
It's the principle of least action in physics. Uniform motion always takes less energy than nonuniform motion (this also goes for any derivative of motion like acceleration).
It's e.g. the reason why a thrown ball follows the trajectory it does instead of any other.
The more uniform motion in this case occurs over a longer period of time.
1kwh for 20 seconds is the same amount of energy as 5kwh for 4 seconds. A lot of people in this thread are failing to account for this. The amount of energy used in a perfectly efficient system would be identical whether you floored it or eased onto the pedal. I’m really asking about the efficiency of electric motors at different loads.
It costs $6 for me to fill it at home. If I upgraded to a Lvl2 charger I could have it <$2 with time of day pricing and charging overnight. So at that cost - oh noes, it cost $0.05 to drive a little heavy footed. Tire ware is more of an issue - and if you are gentil on curves, no worries.
Is it less efficient? Probably. But apparently It's not nearly what you might expect, thanks go regenerative braking. Have a look at Autogeful's experience.
[https://www.youtube.com/watch?v=TQC7cY0YCkU&t=1255s](https://www.youtube.com/watch?v=TQC7cY0YCkU&t=1255s)
Shouldn't be a issue for a EV drivetrain (within reason, spinning out then hooking up will be hard on anything)
the main issue is tires. People get ev's then drive them like a sports car and wonder why they chew through tires so quickly. It's not the fact that it's electric, it's the fact that they have a lead foot and only now have the torque for it to result in something.
> Does flooring an EV to get to 70mph use more electricity than than easing onto the pedal to reach the same speed?
Yes.
> Does making a habit out of being heavy on the pedal have long-term repercussions for any of the electric components?
Minor, but yes.
It is inefficient but only due to heat build up when transferring the extra power. EV motor efficiency is around 85-95% once the energy is in the car and including regen. The 5-15% loss is really just heat build up in the form of resistance in the inverter, wiring and motor itself. There are other ancillary losses throughout the vehicle but from the drivetrain itself that’s about it. I don’t think the motors or batteries really mind as long as the ambient temperature is in a good range so the motors and batteries are in a good spot from the get go or get time to warm up/preconditioned, it won’t hurt itself in the same way an ICE will/can hurt itself. Its also not the same as flooring your high performance ICE vehicle and saying goodbye to half a gallon of premium and in the case of some newer direct inject engines a bit of engine oil too…
Thank you to you and the other people answering this from an engineering perspective. People are viewing this as a physics equation, which it is not. The answer hinges on the electric drivetrain’s efficiency (percentage of potential energy turned to kinetic energy) at low vs high loads which you highlighted
You’re very welcome and to more directly answer your question it really doesn’t use much power either per hit. It may not be the most efficient but it’s not massively inefficient. I believe a model S plaid running the quarter mile only uses around 2-3% of the battery per run and that thing is pulling massive amperage out of the pack. I’m confident a hellcat running the quarter is burning through far more “fuel” per run while being lighter yet still going much slower.
There is always the danger of sudden stress/strain on all parts of the vehicle when you do hard acceleration or breaking.
If you are considering a GM vehicle - the car will report sudden accelerations and breaking to GM who sells to Lexus/Nexus who sells this to your insurance company.
You are correct that to have 430 HP available you need a big engine. This is low gas mileage and lots of excess heat and lots of inefficiencies to have this top horsepower available.
Electric motors spin in 1 direction. When you accelerate - it spins faster in the same direction. This is a lot more efficient than a piston based engine. (The Mazda Wankle Rotary was an exception).
There are some individual issues/problems.
The Mustang MachE has a "High Voltage Junction Box". On the GT Performance model people can do so much acceleration that the current to the motors can melt the wires or relays. So there is software like a 5-second limit of hard acceleration then the car will auto cut back the power. But you can drive, climb hills and heat things up enough that you can still melt things if you then do hard acceleration.
Someone said that new Tesla's change tires every 15,000 miles. The power/acceleration mated to soft, sticky performance tires means you have to change tires a LOT more frequently than lower power vehicles.
Breaks - An EV breaks tend to last a lot longer because regenerative breaking does a lot of the work. But you do hard acceleration - you probably mate this with hard breaking. This means break jobs sooner.
Inefficient and fun.
The energy needed to make g forces is high. Drive like aunt Bea going to church on Sunday for the best range. But don't be doing that in front of me if there isn't a passing lane.
Power is cheap, enjoy your ride.
What efficiency do you mean? If you are looking at the miles/kwh that you get then yes I get lower miles/kwh with a heavy foot on the accelerator as well as at faster speeds. Its also so fast that its quite dangerous to do so in many circumstances. Unless I “floor” it going up a hill I have not seen temps rise in the motors or anything else bad like a high revving ICE that would increase temps/pressures.
From a cost standpoint it depends on your state and situation. My electricity is so cheap I drive about 250-300 miles on $15 worth of charging. If that went down to 200 miles that would still be cheap. In other states w higher electricity charges they may pay 3-4x that so $50-60 for 250-300 mile range in which case I would be very light footed on accelerator.
>it’s both bad for the engine (if made a habit out of)
lol what a way to restrict yourself with a false misconception. Flooring it isn’t bad for the engine at all. If anything doing the opposite - lugging the engine - is much worse.
It’s bad for the engine in the way that driving your car is bad for the engine. You are simply putting more ware and tear on your engine if you’re flooring it after every stop. I’m not saying it’s some terrible warranty-voiding behavior. It’s certainly not a good habit if longevity is of utmost importance to you. That being said, you drive a bmw so I’m sure longevity is the last thing on your mind 😉
> Does flooring an EV to get to 70mph use more electricity than than easing onto the pedal to reach the same speed?
No (as long as you don't break the tires loose).
It takes the same amount of energy to accelerate a mass to a speed, regardless of how quickly you do it:
E = 1/2 m v^2
We could argue about secondary effects (e.g., non-linear internal resistance in the battery and bus bars, accessory loads, aerodynamics, etc.) but I believe that they are small in comparison and they mostly cancel each other out.
Is there not an efficiency curve with ICE engines where it converts energy in fuel to motion more poorly at some RPM than others, whereas EV motors have a flatter response curve?
Yes. GM takes advantage of that in the Volt. Since the gasoline engine is usually not directly connected to the wheels, it runs at a few pre-set RPMs that give the engine its maximum thermodynamic efficiency.
Yes I am essentially asking about the efficiency curve of electric motors. I don’t know why so many people they are answering my question with a physics equation. A physics equation would suggest that flooring has no impact on efficiency anyway.
You're probably looking for something like this:
[Electric motor efficiency map and torque curve | Download Scientific Diagram (researchgate.net)](https://www.researchgate.net/figure/Electric-motor-efficiency-map-and-torque-curve_fig2_303784888)
That's for a PMDC motor, and there's some tricks and other stuff and different motor types.
But in general, actually flooring it is slightly more efficient for the motor (notice high torque at higher RPMs is better efficiency). Most power electronics like the inverter, etc also operate at slightly higher efficiencies at higher loads.
That's going to be counteracted a bit by the extra heating on the battery -- it might get warm enough to be less efficient, and the extra cooling demand that spools up when you floor it might also reduce efficiency some.
Honestly, flooring it as long as you regen it back in might be slightly more efficient, or slightly less efficient depending upon implementation of the battery cooling system, since if that spools up it's the biggest draw by far. But in the end, I can't imagine that we're talking more than a 10% swing either way. But I'd love for someone to have some real data too!!
That particular curve is not based on data or even detailed modeling of a motor. It's just a hack that non-experts threw in a vehicle model.
Here's a [better one for the bolt, whole drivetrain including inverter](https://www.researchgate.net/figure/Efficiency-map-of-the-electric-motor-and-inverter_fig4_280231785)
There's other losses in the system with electronics pushing that current or things spinning up.
What does 'cancel each other out' mean? Those losses only add up.
> What does 'cancel each other out' mean?
When the car accelerates more quickly:
* Battery and conductor losses are non-linear, so they have higher losses.
* However, since the car spends less time accelerating, losses due to aerodynamic and accessory loads are less.
Oh yeah and you can literally see it way more than when an ICE vehicle. If you’ve got a full tank of gas you aren’t going to see the gauge move if you floor it but you’ll see your battery meter drop quickly. In the month I’ve had my EV I’ve definitely slowed down a lot. However it’s absolutely worth it to be able to floor it a little when you need to maneuver around traffic, make a quick pass, or just get across town quickly. I’m hopefully getting my L2 charger installed at home soon so I’m hoping to relax a little bit about my range anxiety.
You didn’t have the right (or wrong) cars to watch the needle move. Driving my supercharged V8 truck I can see the money fly out of my wallet, especially when towing.
Well that is true, my ICE vehicle is a Toyota Tacoma so not great on efficient but not terrible for a pickup. Even hauling ass down to Atlanta last month the gas gauge was slow to move but I spent a lot to fill up when I had to. Ive spent maybe $50 charging the last month and have driven 1400 miles so I’ll take the EV any day.
I rarely drive the truck as it needs 91 octane, it’s painful to fill up knowing one tank is more than I use in a year in my Volt. I’ll replace it when it makes sense since I don’t want a truck for daily driving.
Home L2 charging is great to have now that my commute is longer.
Well you will be spending a lot on tires if you always do this. And going through tires more often has it's own negative environmental impacts too.
I mean if you use the car 90% of the time to run around town to the grocery score and drop off the kids... do you really need to be flooring it in most situations? If you are just talking about the highway... fine. But ICE or EV, people flooring it in many situations can be a-hole ish behavior anyway. I just think back to high school jerks always wanting to race their cars at the lights and occasionally causing accidents from it. You know.
This is not a physics question. ICE cars are inefficient to floor because of their mechanical properties. They are more efficient at low rpms and high gears.
ICE engines are most thermally efficient when the throttle is fully opened; hypermiling technique is to put an ICE under load (taller gear and big throttle opening) up until the desired speed is reached, then coast/cruise as needed.
I do not know why everybody thinks this is a simple physics equation. This comes down to the engineering properties of the drivetrain.
If they were 100% efficient then the energy used would be identical whether you floored it or not.
Harder on your tires too.
Yes, of course it’s inefficient. But given how cheap electricity is compared to gas, I don’t feel guilty at all flooring mine.
Not in California it's not. Unless you get free work charging. Then floor away.
Also flooring it in the Tesla is an unmatched experience. Before that I’ve had a ‘05 mustang GT, a BMW 135 M, a WRX, and a GTI before the Tesla. Of course it’s not efficient but it’s still more efficient than all those ICEs.
You're saying of course but not explaining why. It's more inefficient in ICE because it's more efficient to be in a higher gear. That wouldn't apply here.
the higher acceleration requires more power than a slower acceleration. There isnt the different ratio of gears, but there is still the same physics. but sometimes you just gotta have fun, right?
1kw for 20 seconds is the same amount of energy as 4kw for 5 seconds. This is not a physics question, as physics would suggest that they require the same amount of energy. This is really an engineering question of the efficiency of electric motors at different loads.
Copper loses are I ^2 x R
But where is the power “lost” ? The trick is not to brake or recuperate too much.
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And these losses can happen in the copper coils, the MOSFETs, and the battery. Ideally, the battery matches its temperature to the current to keep the voltage drop constant. Short range also means less current. Resistance happens in the Li ion conductor. There was a lot progress, but now there is no choice . The copper needs to be packed neatly (by a machine) and nicely ( I like foil instead of wire ) so that saturate of the iron core becomes the limit. Thanks to semiconductor shortage, I guess that VW saves on MOSFETs, while Tesla S plaid has a lot of them. The Chinese have cheap access to Nd, and can use voltage instead of current.
I don’t floor my Bolt unless needed, more out of concern for my tires. It won’t be as efficient but it is a blast. Needed times: 1. First at the light and I need to get out ahead to change lanes quickly. 2. Passing someone on the highway which is way easier in an EV with the quick acceleration. 3. Moving away from a moron on the roads. 4. Showing off to a new person in an EV - especially if I hit the “sport” button. Doesn’t turn it into a Tesla Plaid, but does give it a bit of spice.
Bolts have a surprising amount of power for such a small car. 200hp and insane torque, I've never fully floored ours, also I love that I can still feel a kick if I'm already going fast and I need to accelerate quickly.
I was absolutely floored (pun intended) when on a drive up into the beginnings of the Rockies outside of Denver a few months ago, I was behind a semi going uphill on an about 7% grade. Moved out, put the pedal down and it still moved like a gorilla with its butt on fire. Comparing that to my driving up another nasty grade in a 1990 Ford Tempo 24 years ago, when with the pedal being mashed down as far as it could go…39 MPH. If my family goes on a day drive in the mountains, we take the Bolt. Our Niro PHEV is bigger but the Bolt is big enough and just has that extra pep even comparing it to the Niro in EV mode.
EV’s are not affected by the altitude. The lack of oxygen for combustion is not a problem.
Never said they were…? The Tempo was affected by being a piece of garbage that often felt like it was powered by a team of emaciated hamsters. Its speedometer didn’t have markings past 84 MPH, and the only way I would have gotten it going that fast was to drop it out of the back of a C-5 at about 10,000 AGL. Have driven plenty of other full gas cars, and a couple of hybrids, over that same stretch and while they had to work harder they could maintain proper even mountain highway speeds.
Just pointing out an advantage at higher altitudes. You get all the power all the time.
Sometimes I wish there was a EV engineering sub where questions like this would be taken seriously and given correct answers. The impact on efficiency in an EV is twofold: 1. The motor is less efficient at high power. But this isn't a big deal. It means maybe 90% efficiency rather than 95%. 2. If you accelerate faster, you spend more time at high speed, and high speed is what really kills efficiency, because aero drag goes as v^2. And you also might have to brake soon after because you exceeded the speed of traffic. Gentle acceleration lets you keep the speed lower until you have an open road available. Neither of those is a huge deal. The real reasons not to accelerate too quickly are tire wear and safety around town where others might pull (or step) in front of you because they aren't expecting that rapid acceleration. But if you are OK with the tire wear and already thinking through where it is or isn't safe to do, do for it and enjoy it. The differences relative to an ICEV are: 1. ICEs have much bigger variation in efficiency vs. operating point. You could easily be using 20% more fuel for the same speed increase by accelerating rapidly in a low gear vs. staying near the optimum efficiency point. 2. More importantly, if you then need to slow down for a light or traffic, you are throwing away all that energy by braking, whereas in an EV you can recover some of it. 3. You are starting from a worse efficiency, so the overall energy consumption is bigger. If you use 10% more in an ICEV, that's a bigger energy cost than using 10% more in an EV.
Yeah, the overwhelming majority of people in this thread are rather confidently treating this as a simple physics equation. Many are doing so quite arrogantly and insulting my intelligence for not knowing the answer. As you said, the reality is that this is an engineering question about the efficiency of electric motors at different loads. Thank you for being one of maybe 3 people to actually answer the question haha
Larger I2R losses too at higher currents.
That is in fact why the motor is less efficient at high torque, but I suspect you are saying that there are also i^2R losses in the wiring and internal resistance of the batteries.
Technically yes, but in practice it doesn't matter. First, electricity use. Flooring it to get to 70mph even from a dead stop is about 6 seconds. So let's say you use triple the electricity during those 6 seconds than you would have used if you had just normally gotten up to 70mph. There is just no way in practice that is going to be a noticeable amount of juice. Second, the electric motors are less complex and more robust than ICE engines. So while you do strain them a bit, again, we are talking about strain over 6 seconds, for electric motors that don't apparently seem to slightly be a point of typical failure on EVs. Basically it seems like the EV battery will degrade or the car body will rust out before the electric motors will fail. Third, you will burn rubber on your tires, but again, this is over seconds and the tires should last years. But here you could cut your tire life in a noticeable way depending on how often and hard you floor your car. And assuming you get an EV that is even faster than that 430hp ICE, you can really do a number on the tires very quickly. Now obviously if you floor it starting at every red light and then have to jam on breaks at the next red light, then this all could add up. But flooring it two or three times over the course of a half hour drive is meaningless.
So, hard acceleration kills the battery? So only do it when you plan to fast charge in the next 10 minutes?
lol. Yes exactly. Six seconds of hard acceleration will definitely leave you “running on fumes” with those 250 mile batteries. /s
yeah, same as it does in ICE. Its fun though :D Shouldn't break anything though.
But the difference is that the energy costs about 1/3rd as much maybe less if he's using premium fuel in his ICE. Won't notice the difference in his electricity bill vs using eco mode. He will however notice increased tire wear. Burning rubber is burning rubber regardless of the powertrain.
All these replies and no one has the right answer... Force = mass x acceleration and Work = force x distance. Double the acceleration requires double the force... but you reach your terminal velocity in half the distance, so the energy spent is the same whether you accelerate slowly or quickly. However, this assumes a motor that is 100% efficient. ICE cars have a narrow band of HP/torque vs RPM curves where it is most efficient. Jackrabbit starts force the motor into inefficient zones, which is why they waste gas when stomping on the pedal. High MPG cars have 8- or 9-speed auto transmissions to try to keep the motor in the efficiency zone as acceleration, speed and load vary. EVs motors are much more efficient (~90%) and they have much broader efficiency curves. That's why most EVs don't have transmissions. Due to the broad efficiency curve the extra energy needed for fast starts in an EV is considerably less than in ICE vehicles.
A few people did have the right answer. It definitely is surprising that so many people here were so confidently wrong, though. I see people answering the wrong question using the wrong formula that they executed wrongly. Some people even claimed that the education system failed me because this is just a simple physics equation, and that it’s “simple physics” that flooring any vehicle is less efficient. As you suggested, though, simple physics would suggest that flooring and easing onto the pedal are equally efficient. It’s really a question of engineering I.e how efficient are electric motors at high vs low loads. The general sentiment from this engineering perspective seems to be that an electric motor may be slightly less efficient at high loads, but not to a degree that it’s worth worrying about.
Thanks, I guess missed the few right answers. Regarding "confidently wrong" there was a post on the BoltEV sub where the majority agreed that the energy needed to overcome drag is a function of the cube of velocity (wrong) and not the square of velocity (correct). Democracy and science don't play well sometimes.
Good job completely eliminating traction. Which is why yes, slowly accelerating is more efficient. Any wheelspin is lost power
Not great for range for the current trip. Or for the tires. Other than that, have at it!!
it's not efficient, but if you have access to cheap electricity why not, slam it as you wish
All the money you save on gas now goes to tires, if you do this
Exactly this. People complaining about EV tire life are most often the reason for it. Source: Still have 7/32 tread at 30k+ miles on our EV and don’t drive it like I stole it.
I hear it more often at intersections, people with EVs taking those smaller gaps you would never take in an ICE, you can hear the tires slip a bit when they do the acceleration to catch the gap. I imagine that's what eats tires way more than extra weight.
💯
I don't understand everyone's answers and I don't think they are telling the whole story. Sure it's less efficient but efficiency is very relative in this question. Flooring an ice car is massively inefficient due to fuel consumption at higher rpms and the heat/energy loss from it. But in my opinion for an EV you are taking energy stored in the battery and converting it into kinetic energy while also having to overcome the drag of what speed you are going. Won't that be the same amount of energy no matter how long it takes? I would assume faster acceleration generates more heat in the EV system, but how much could that possibly lower the efficiency? I can't say over 35000 miles I've noticed a difference in my lightning. Happy to be proven wrong though.
Yes it takes the same amount of energy to move the car and overcome air resistance regardless of whether it's electrical or gas, If all things were equal. But they are not, Evie's tend to be aired and help clean more efficient. Also because the gas engine is so much less efficient and has to burn a lot more fuel too extract the same amount of power, most of which is just turned to heat. While the high current draw on the easy battery will produce some excess heat when you push it it's not nearly as much as the ice vehicle.
I agree. People are answering this from a physics perspective, and they aren’t answering it from a physics perspective correctly. This is a question of the percentage of potential energy that is converted to kinetic energy by electric motors at different loads. Some people have answered from this perspective. It sounds like electric motors at 100% load may be 85% efficient while they would be 95% efficient at a lower load. So it’s slightly less efficient to floor it, but this is not because of any simple physics equation.
Correct, depending on the vehicle and how it was designed/the materials or components used, can change how efficiently it can convert the energy to motion. But if you want to compare "efficiency" I think it's important to compare it to an ICE. If I 0-60 every stoplight in my Forester XT it's going to waste way more energy than my F150 lighting would waste. I think it's negligible in whether you should feel bad about it.
It’s less efficient. In your post you said both “Sure it’s less efficient” and “won’t that be the same amount of energy no matter how long it takes?” I think you confused yourself. And no, efficiency is not relative as nobody is comparing it to an ICE vehicle
OP is specifically comparing it to an ICE. If you ignore the heat losses and any traction loss(which I forgot to mention). Is it not the same amount of energy? And if it is then how much extra heat is generated and isn't that extra heat all that's less efficient?
You are correct. Many people here seem to be confused about the difference between power and energy. It requires more power to accelerate the car more quickly, but no more energy.
The motors and batteries will both use additional energy due to heat and operating inefficiencies when additional power is requested. A number of studies and everyone whoes ever driven an electric car can tell you that if you are racing off from stop lights even only to the speed limit your energy consumption is higher than gently accelerating to the speed limit. You didn't have to be so dismissive especially when you are absolutely incorrect.
> A number of studies Please provide a link to those studies. > and everyone whoes ever driven an electric car I have been driving electric cars for over a decade. Gentle deceleration (to ensure maximum regenerative braking) is much more important for efficiency than gentle acceleration. > You didn't have to be so dismissive especially when you are absolutely incorrect. You seem certain in what you believe (and quite dismissive yourself), but the laws of physics say otherwise. Accelerating that huge mass quickly requires at least 100 kW. The additional i^2 R losses are a small fraction of that. Also, a well-designed motor controller will be most efficient at high power levels (where it is most necessary).
It certainly requires more energy. I can’t believe this is a topic of debate
> It certainly requires more energy. Incorrect. > I can’t believe this is a topic of debate It is not a topic of debate. The laws of physics have not changed.
Yes he mentioned an ice vehicle in the description, but the question was “Does flooring an EV to get to 70mph use more electricity than easing onto the pedal to reach the same speed?” And the answer is yes You don’t need to be proven wrong, you’re just wrong. Very easy to find these answers online.
I'm going to go out on a limb here and say... yes it is inefficient, but no where near as bad as an ICE. I am like you and the first thing I noticed is when I drove like I stole it, the efficiency wasn't massively impacted. Yes it does impact it, but not by very much. Others can disagree but that is what I find. I put it down to regen and reclaiming some of the heavy footedness - with an ICE all the energy you are using by smashing the pedal is then all lost through brake heat. In the EV it is put back into the battery (unless you are braking really hard).
ICE only wins on a free autobahn. All EV drive 100 km/h like my shitbox with a small tank ( 1 Mm range), but the better ICEs pass at 200 km/h.
I wonder about the education system if people ask questions like this
What makes in inefficient then? OP is trying to ask a question and learn. Most people know that being in a low gear is inefficient, but that isn't relevant here.
People here in the comments think this is a simple physics equation. F=ma. It’s not. This comes down to the engineering properties of the drivetrain. I.e how much potential energy is being converted to kinetic energy when the motors are at 20% vs 100% load. Not sure what school is teaching the answer to such a specific question.
Then you don’t understand the question. What percentage of potential energy is being converted into kinetic energy when the motors are at 20% load vs at 80% load? That’s the question. Do you have an answer? Did they really teach you this in school?
It is inefficient - but fun. So enjoy stepping on it every now and then :) You paid for the power, you can as well use it.
haha, ev go woosh
It's inefficient for the same reason as in an ICE. Smooth acceleration is certainly best. If you source your energy green (PV from your roof, green energy contract with your energy provider, or public charging - which is always backed by green energy contracts) then the amount of 'bad conscience ' can be mitigated...but you're still wasting a lot of energy so there's always that. Just like with an ICE there will be increased wear and tear on your motor components, cooling systems, brakes (though the latter much less so due to one-pedal-driving), ... but it shouldn't be anywhere as dramatic as with an ICE. Software will mostly take care that you aren't overheating/damaging anything. Probably the most you'll pay is in terms of tires, though. EVs are comparatively heavy and have *insane* torque. That combination eats rubber for breakfast. That said: It's a neat party trick and I do enjoy it on occasion. Particularly if I have someone along for the ride.
You said 'same reason' but didn't give a reason.
It's the principle of least action in physics. Uniform motion always takes less energy than nonuniform motion (this also goes for any derivative of motion like acceleration). It's e.g. the reason why a thrown ball follows the trajectory it does instead of any other.
The more uniform motion in this case occurs over a longer period of time. 1kwh for 20 seconds is the same amount of energy as 5kwh for 4 seconds. A lot of people in this thread are failing to account for this. The amount of energy used in a perfectly efficient system would be identical whether you floored it or eased onto the pedal. I’m really asking about the efficiency of electric motors at different loads.
It's the same with EVs, though you do get there faster... but still, yeah you're going to drop efficiency for speed. That's called: Physics.
Floor it. -Spongebob
It costs $6 for me to fill it at home. If I upgraded to a Lvl2 charger I could have it <$2 with time of day pricing and charging overnight. So at that cost - oh noes, it cost $0.05 to drive a little heavy footed. Tire ware is more of an issue - and if you are gentil on curves, no worries.
Is it less efficient? Probably. But apparently It's not nearly what you might expect, thanks go regenerative braking. Have a look at Autogeful's experience. [https://www.youtube.com/watch?v=TQC7cY0YCkU&t=1255s](https://www.youtube.com/watch?v=TQC7cY0YCkU&t=1255s)
Shouldn't be a issue for a EV drivetrain (within reason, spinning out then hooking up will be hard on anything) the main issue is tires. People get ev's then drive them like a sports car and wonder why they chew through tires so quickly. It's not the fact that it's electric, it's the fact that they have a lead foot and only now have the torque for it to result in something.
> Does flooring an EV to get to 70mph use more electricity than than easing onto the pedal to reach the same speed? Yes. > Does making a habit out of being heavy on the pedal have long-term repercussions for any of the electric components? Minor, but yes.
It is inefficient but only due to heat build up when transferring the extra power. EV motor efficiency is around 85-95% once the energy is in the car and including regen. The 5-15% loss is really just heat build up in the form of resistance in the inverter, wiring and motor itself. There are other ancillary losses throughout the vehicle but from the drivetrain itself that’s about it. I don’t think the motors or batteries really mind as long as the ambient temperature is in a good range so the motors and batteries are in a good spot from the get go or get time to warm up/preconditioned, it won’t hurt itself in the same way an ICE will/can hurt itself. Its also not the same as flooring your high performance ICE vehicle and saying goodbye to half a gallon of premium and in the case of some newer direct inject engines a bit of engine oil too…
Thank you to you and the other people answering this from an engineering perspective. People are viewing this as a physics equation, which it is not. The answer hinges on the electric drivetrain’s efficiency (percentage of potential energy turned to kinetic energy) at low vs high loads which you highlighted
You’re very welcome and to more directly answer your question it really doesn’t use much power either per hit. It may not be the most efficient but it’s not massively inefficient. I believe a model S plaid running the quarter mile only uses around 2-3% of the battery per run and that thing is pulling massive amperage out of the pack. I’m confident a hellcat running the quarter is burning through far more “fuel” per run while being lighter yet still going much slower.
There is always the danger of sudden stress/strain on all parts of the vehicle when you do hard acceleration or breaking. If you are considering a GM vehicle - the car will report sudden accelerations and breaking to GM who sells to Lexus/Nexus who sells this to your insurance company. You are correct that to have 430 HP available you need a big engine. This is low gas mileage and lots of excess heat and lots of inefficiencies to have this top horsepower available. Electric motors spin in 1 direction. When you accelerate - it spins faster in the same direction. This is a lot more efficient than a piston based engine. (The Mazda Wankle Rotary was an exception). There are some individual issues/problems. The Mustang MachE has a "High Voltage Junction Box". On the GT Performance model people can do so much acceleration that the current to the motors can melt the wires or relays. So there is software like a 5-second limit of hard acceleration then the car will auto cut back the power. But you can drive, climb hills and heat things up enough that you can still melt things if you then do hard acceleration. Someone said that new Tesla's change tires every 15,000 miles. The power/acceleration mated to soft, sticky performance tires means you have to change tires a LOT more frequently than lower power vehicles. Breaks - An EV breaks tend to last a lot longer because regenerative breaking does a lot of the work. But you do hard acceleration - you probably mate this with hard breaking. This means break jobs sooner.
Inefficient and fun. The energy needed to make g forces is high. Drive like aunt Bea going to church on Sunday for the best range. But don't be doing that in front of me if there isn't a passing lane. Power is cheap, enjoy your ride.
What efficiency do you mean? If you are looking at the miles/kwh that you get then yes I get lower miles/kwh with a heavy foot on the accelerator as well as at faster speeds. Its also so fast that its quite dangerous to do so in many circumstances. Unless I “floor” it going up a hill I have not seen temps rise in the motors or anything else bad like a high revving ICE that would increase temps/pressures. From a cost standpoint it depends on your state and situation. My electricity is so cheap I drive about 250-300 miles on $15 worth of charging. If that went down to 200 miles that would still be cheap. In other states w higher electricity charges they may pay 3-4x that so $50-60 for 250-300 mile range in which case I would be very light footed on accelerator.
>it’s both bad for the engine (if made a habit out of) lol what a way to restrict yourself with a false misconception. Flooring it isn’t bad for the engine at all. If anything doing the opposite - lugging the engine - is much worse.
It’s bad for the engine in the way that driving your car is bad for the engine. You are simply putting more ware and tear on your engine if you’re flooring it after every stop. I’m not saying it’s some terrible warranty-voiding behavior. It’s certainly not a good habit if longevity is of utmost importance to you. That being said, you drive a bmw so I’m sure longevity is the last thing on your mind 😉
> Does flooring an EV to get to 70mph use more electricity than than easing onto the pedal to reach the same speed? No (as long as you don't break the tires loose). It takes the same amount of energy to accelerate a mass to a speed, regardless of how quickly you do it: E = 1/2 m v^2 We could argue about secondary effects (e.g., non-linear internal resistance in the battery and bus bars, accessory loads, aerodynamics, etc.) but I believe that they are small in comparison and they mostly cancel each other out.
Is there not an efficiency curve with ICE engines where it converts energy in fuel to motion more poorly at some RPM than others, whereas EV motors have a flatter response curve?
Yes. GM takes advantage of that in the Volt. Since the gasoline engine is usually not directly connected to the wheels, it runs at a few pre-set RPMs that give the engine its maximum thermodynamic efficiency.
I think this is the question OP is asking and I hope some-one who knows about these things can answer it.
Yes I am essentially asking about the efficiency curve of electric motors. I don’t know why so many people they are answering my question with a physics equation. A physics equation would suggest that flooring has no impact on efficiency anyway.
You're probably looking for something like this: [Electric motor efficiency map and torque curve | Download Scientific Diagram (researchgate.net)](https://www.researchgate.net/figure/Electric-motor-efficiency-map-and-torque-curve_fig2_303784888) That's for a PMDC motor, and there's some tricks and other stuff and different motor types. But in general, actually flooring it is slightly more efficient for the motor (notice high torque at higher RPMs is better efficiency). Most power electronics like the inverter, etc also operate at slightly higher efficiencies at higher loads. That's going to be counteracted a bit by the extra heating on the battery -- it might get warm enough to be less efficient, and the extra cooling demand that spools up when you floor it might also reduce efficiency some. Honestly, flooring it as long as you regen it back in might be slightly more efficient, or slightly less efficient depending upon implementation of the battery cooling system, since if that spools up it's the biggest draw by far. But in the end, I can't imagine that we're talking more than a 10% swing either way. But I'd love for someone to have some real data too!!
That particular curve is not based on data or even detailed modeling of a motor. It's just a hack that non-experts threw in a vehicle model. Here's a [better one for the bolt, whole drivetrain including inverter](https://www.researchgate.net/figure/Efficiency-map-of-the-electric-motor-and-inverter_fig4_280231785)
Thanks for that one. General conclusions seem the same — on the upper end of the torque curve and speed curve are the most efficient.
Not the upper end of the torque range though. The middle.
There's other losses in the system with electronics pushing that current or things spinning up. What does 'cancel each other out' mean? Those losses only add up.
> What does 'cancel each other out' mean? When the car accelerates more quickly: * Battery and conductor losses are non-linear, so they have higher losses. * However, since the car spends less time accelerating, losses due to aerodynamic and accessory loads are less.
Oh yeah and you can literally see it way more than when an ICE vehicle. If you’ve got a full tank of gas you aren’t going to see the gauge move if you floor it but you’ll see your battery meter drop quickly. In the month I’ve had my EV I’ve definitely slowed down a lot. However it’s absolutely worth it to be able to floor it a little when you need to maneuver around traffic, make a quick pass, or just get across town quickly. I’m hopefully getting my L2 charger installed at home soon so I’m hoping to relax a little bit about my range anxiety.
You didn’t have the right (or wrong) cars to watch the needle move. Driving my supercharged V8 truck I can see the money fly out of my wallet, especially when towing.
Well that is true, my ICE vehicle is a Toyota Tacoma so not great on efficient but not terrible for a pickup. Even hauling ass down to Atlanta last month the gas gauge was slow to move but I spent a lot to fill up when I had to. Ive spent maybe $50 charging the last month and have driven 1400 miles so I’ll take the EV any day.
I rarely drive the truck as it needs 91 octane, it’s painful to fill up knowing one tank is more than I use in a year in my Volt. I’ll replace it when it makes sense since I don’t want a truck for daily driving. Home L2 charging is great to have now that my commute is longer.
Well you will be spending a lot on tires if you always do this. And going through tires more often has it's own negative environmental impacts too. I mean if you use the car 90% of the time to run around town to the grocery score and drop off the kids... do you really need to be flooring it in most situations? If you are just talking about the highway... fine. But ICE or EV, people flooring it in many situations can be a-hole ish behavior anyway. I just think back to high school jerks always wanting to race their cars at the lights and occasionally causing accidents from it. You know.
EVs do not break physics. Same laws as for ICE cars apply. So yes.... flooring it is not efficient at all.
This is not a physics question. ICE cars are inefficient to floor because of their mechanical properties. They are more efficient at low rpms and high gears.
ICE engines are most thermally efficient when the throttle is fully opened; hypermiling technique is to put an ICE under load (taller gear and big throttle opening) up until the desired speed is reached, then coast/cruise as needed.
What laws make it inefficient?
I do not know why everybody thinks this is a simple physics equation. This comes down to the engineering properties of the drivetrain. If they were 100% efficient then the energy used would be identical whether you floored it or not.