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There's alot of greenwashing when it comes to electriv vehicles no doubt. One major point I noticed that seems to slip through the cracks is that they don't need to be as fast as they are. The faster they are, the more they consume right? couldn't we reduce the amount of batteries in an EV if it didn't go so fast? They have passenger seats too that probably go unused for the most part, couldn't we push for single passenger (driver only) EVs, then everyone could afford one and we could all be in our own bubble that uses alot less energy.

Why are EVs tagged as green when they are engineered or marketed for performance which consumes in excess of?

Edit: note i didn't mention fossil fuels because this question has nothing to do with them. If anything is to be compared it's the EV offerings vs capabilities, from an engineering or technological point of view. I tagged it with fuel-efficiency referring to the battery (fuel) cells. is there a more appropriate tag?

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    The goal of car manufacturers isn't to protect the environment (otherwise they wouldn't be car manufacturers) - their goal is to make money. If marketing EVs as fast, sporty, manly etc. makes them more money, that's what they'll do.
    – thosphor
    Feb 13 at 13:36
  • who put these people in charge. governments shouldn't be able to promote a better future and a throw away society at the same time. frustrating
    – yarns
    Feb 14 at 0:40
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    They're tagged as green compared to the similar fossil alternatives. Which all things considered is sort of correct. In a similar way, what you propose would be green compared to a larger EV, but for small distances a lot less against, for instance, an electric bicycle. Or for putting 50+ passengers in one electric bus, etc. For the exact same reasons you're stating.
    – stijn
    Feb 15 at 10:11
  • i agree we need to size EV fit for purpose but I've been looking at EVs on the road and they're almost always carrying no passengers. they could be more greener, if this is the intended use case then people should know that they're not helping us save the environment. I know it might be better but we are capable of alot more in EVs
    – yarns
    Feb 16 at 7:00

2 Answers 2

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The faster they are, the more they consume right?

No.

In conventional vehicles, especially those powered by a gasoline engine, this is true. Gasoline engines are very inefficient at part-load. So you want to load a gasoline engine at 50% of its power producing capacity or so. The trouble is, if you make a car with a big engine for fast driving and quick acceleration, and then don't choose the option of driving fast, it consumes maybe 10% of the maximum power production. This is very inefficient and has huge fuel consumption.

But electric vehicles make everything different. Electric vehicle speed is primarily determined by the ability for the battery to supply power, secondarily by the size of power electronics and motors.

Power electronics and motors aren't inefficient at part load, in fact they can perfectly well run at part load. There's some minimal power consumption for an idling inverter, but it isn't anywhere comparable to the fuel consumption of an idling engine.

Making the battery able to supply more power of course makes it heavier, so it is true to some degree that fast electric vehicles consume more power. However, most power is consumed in air resistance, and rolling/uphill/acceleration resistance determined by mass only comes in the second, third and fourth places (not necessarily in that order). The effect of uphill and acceleration resistance on electricity consumption is much reduced by the ability to do regenerative braking, which can't be done in internal combustion engine vehicles.

So basically the main worry is that to make a heavy EV, it will have more mass, which increases rolling resistance. But rolling resistance only makes about 20% of the total resistance, and battery mass makes about 25% of the weight of an EV, so that's not a major worry. If you increase battery mass by 50%, maybe you increase EV electricity consumption by few percent or so, not a major issue. And as a bonus, heavier batteries have more capacity so the range will be increased much.

couldn't we reduce the amount of batteries in an EV if it didn't go so fast?

No. EV battery weight is primarily determined by the ability to be quickly charged and ability to have enough range. Remember that in long trips, you don't charge to 100% because it's slow (you only charge to 100% at home then during the trip do fast charges to 80%). You never run the battery completely empty because that's a huge risk, you can be stranded on the side of the road. So you are using 20%-80% or only 60% of the battery capacity.

So an EV that has 350 km of real-world range in very cold or very hot conditions on the freeway (which would be 500 km ideal range at slower speeds), allows you to use 60% of it during long trips that include fast charging, or only 210 km.

Does 210 km sound great? It's only a couple of hours of freeway driving. Some people might want the ability to drive longer.

And if you charged every 105 km, which would allow halving the battery capacity, this would also halve the fast charging rate. So you would spend twice the time at fast chargers, not ideal.

So EV battery capacity is determined by fast charging speed and real-world range in the conditions you drive in, which dictates battery mass, which just happens to give the potential for a very fast acceleration and tremendously high speeds, because EVs aren't inefficient at part-load. So if an EV has the potential for a very fast acceleration and very high speeds, why not realize that potential and install good electric drivetrain on the car, since the battery is clearly capable of supporting a good powerful drivetrain?

They have passenger seats too that probably go unused for the most part, couldn't we push for single passenger (driver only) EVs, then everyone could afford one and we could all be in our own bubble that uses alot less energy.

I used to drive a car with five seats, Toyota Yaris. It was a bit crowded for hauling cargo.

When I have to transport only myself in good weather, I ride bike.

My car fulfills poor-weather transportation and hauling of goods. Hauling of goods requires a big car, bigger than Toyota Yaris which still had five seats.

I couldn't imagine how horrible it would be to own a car with just one seat.

Why are EVs tagged as green when they are engineered or marketed for performance which consumes in excess of?

Because they are green. Performance doesn't hurt EVs because they are efficient at part-load.

Reducing the length of car doesn't reduce its air resistance, in fact it increases it because it's a less aerodynamic design.

Reducing the height is not an option in many cases, since humans have a certain height and need space to sit in.

So reducing the width is the only option. You could make a two-seater car, with two seats (one in front, one in back), but it's less useful for hauling cargo than a five-seater car since wide cargo can't be transported. I don't think many people would buy such a car, even though it would have less air resistance.

It just happens that cars that are as wide as cars currently are, are optimal for their users.

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  • Congratulations for your well reasoned and realistic answer. Is not common at all to find this kind of answers in generic forums about cars.
    – jap1968
    Feb 15 at 21:59
  • @jap1968 did you do the amount of research required by this answer? i'm about to, doesnt seem realistic to provide % values without any actual voltages or references to current and capacitance or formulas.
    – yarns
    Feb 16 at 4:25
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Such vehicles do exist. There are slower, 1 or 2 person EVs with smaller batteries, such as the Citroen Ami, Silence S01, Renault Twizy, Electramechannica Solo, Arcimoto FUV. Unfortunately, they run up against a few problems that limit the size of the market. Although they may be cheaper than a full-size EV, they are not cheap compared to second-hand cars, or even the cheaper end of new petrol cars. Although a car owner may do 90%+ of journeys with just 1 person in the car, they still need an option for those occasions when they need to transport more people or stuff. One potential solution would be greater options for car sharing, where people can use a different cars depending on what they need to do that day. In answer to the second part of the question, EVs are tagged as green because changing behaviors to get people out of 5-seat cars is unpopular and difficult, and for a large section of the population, EVs are the probably the only alternative to to fossil fuel cars that would be palatable.

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  • yeah I drive a 5 seater station wagon loaded with tools I never use but I looked for a job close to home and have been working 3 minutes drive from my place for over a year now compared to average 1 hr trip. It's not in most peoples mindset yet the green slogan is everywhere
    – yarns
    Feb 14 at 0:35

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