Why it's time to get over your EV range anxiety [Arstechnica]

[fishbert]

https://arstechnica.com/cars/2023/03/why-its-time-to-officially-get-over-your-ev-range-anxiety/

“Smaller batteries have all kinds of advantages,” [U of Delaware professor William Kempton] said, among them cost and weight, not to mention smaller carbon footprints because they require less electricity and fewer metals like lithium. And Kempton added another benefit—“you’re reducing pedestrian injuries”—because the cars weigh much less than models with large batteries, which diminishes the severity of collisions with people and other vehicles.

About the only time that the longer range is essential is for cross-country trips, when a vehicle with a larger battery is going to need fewer stops. But cross-country driving trips are rare for most drivers.

“It’s cheaper to rent a car for two days (per year) than to spend 10 grand on a much bigger battery,” Kempton said.

The co-authors, who also included researchers from Dalhousie University in Nova Scotia and Georgia Tech, looked at scenarios involving EVs with various sizes of batteries and charging systems. They found that longer-range vehicles would rarely, and, for some drivers, never, need to use the upper reaches of their range.

The paper helps to confirm some things we knew or at least strongly suspected. Much like drivers don’t need gigantic pickup trucks to get groceries, drivers don’t need 300 miles of range when the large majority of their trips are 20 miles or less.

“A lot of the news lately has been around EV range getting longer and longer, but the fact is, if a lower-range car will do, it’s going to be better for the customer’s wallet and for the environment,” [Stephanie Searle of the International Council on Clean Transportation] said in an email. “Lower range means smaller batteries, and that reduces the upstream environmental impact from mining and battery production. Smaller batteries also means more efficient EVs that cause lower (greenhouse gas) emissions from electricity production.”​

 

[pictsidhe]

https://arstechnica.com/cars/2023/03/why-its-time-to-officially-get-over-your-ev-range-anxiety/

“Smaller batteries have all kinds of advantages,” [U of Delaware professor William Kempton] said, among them cost and weight, not to mention smaller carbon footprints because they require less electricity and fewer metals like lithium. And Kempton added another benefit—“you’re reducing pedestrian injuries”—because the cars weigh much less than models with large batteries, which diminishes the severity of collisions with people and other vehicles.

About the only time that the longer range is essential is for cross-country trips, when a vehicle with a larger battery is going to need fewer stops. But cross-country driving trips are rare for most drivers.

“It’s cheaper to rent a car for two days (per year) than to spend 10 grand on a much bigger battery,” Kempton said.

The co-authors, who also included researchers from Dalhousie University in Nova Scotia and Georgia Tech, looked at scenarios involving EVs with various sizes of batteries and charging systems. They found that longer-range vehicles would rarely, and, for some drivers, never, need to use the upper reaches of their range.

The paper helps to confirm some things we knew or at least strongly suspected. Much like drivers don’t need gigantic pickup trucks to get groceries, drivers don’t need 300 miles of range when the large majority of their trips are 20 miles or less.

“A lot of the news lately has been around EV range getting longer and longer, but the fact is, if a lower-range car will do, it’s going to be better for the customer’s wallet and for the environment,” [Stephanie Searle of the International Council on Clean Transportation] said in an email. “Lower range means smaller batteries, and that reduces the upstream environmental impact from mining and battery production. Smaller batteries also means more efficient EVs that cause lower (greenhouse gas) emissions from electricity production.”​

For 95% of my driving, the SE range is fine. For that other 5%, it gets tedious. Fast chargers being sparse is a major factor, but improving. With their reliability, you really need to have some kind of charging plan B. That often results in leg lengths of under 100 miles for me. The longer legs need to hit a higher %, which is slow. The upcoming J01 with around 50% more range, will dramatically improve that, with legs over 50% longer.

 

[CoachCookie]

While I agree there's no need for huge battery 8000+ lb EV trucks to be driven daily, the same argument can be made for sports cars that get either poor fuel mileage or offer very little practicality...and that's when I'd have to tuck my tail and walk away.

 

[AndysComputer]

While I agree there's no need for huge battery 8000+ lb EV trucks to be driven daily, the same argument can be made for sports cars that get either poor fuel mileage or offer very little practicality...and that's when I'd have to tuck my tail and walk away.

I live in hope that pickup trucks will become a less popular choice when people find their price (due to battery size), long charging time (due to battery size) and public charging cost (due to battery size) are not worth living with. I can dream anyway…

As for sports cars, we’ll, almost every EV is a performance these days so no need to feel guilty, lol!

 

[sacharama]

I knew what I was getting into and what to expect when I got the SE. But a couple of things that the authors stated are not quite true.

1. I don't think a lighter car would make it safer when it's involved in a collision in regards to pedestrians safety. A 3000 lbs car crashing into a pedestrian would not cause less injury than a 5000 lbs car crashing into a pedestrian.

2. It is not just a cross country road trip that a longer range would make a significant difference in the driving experience as well as the practical application. Some part of country that is within 100 miles of urban/suburban area don't have any public DC chargers, therefore a short range EV like the SE would encounter a challenge if you need to make a round trip to such location. So in those instances, a longer range EV would not have such issue.

 

[Puppethead]

1. I don't think a lighter car would make it safer when it's involved in a collision in regards to pedestrians safety. A 3000 lbs car crashing into a pedestrian would not cause less injury than a 5000 lbs car crashing into a pedestrian.

Studies may indicate otherwise: Increases in vehicle weight cause a spike in the rate of fatalities, studies show

 

[sacharama]

Studies may indicate otherwise: Increases in vehicle weight cause a spike in the rate of fatalities, studies show

Studies are not created equally. Just because there are studies published does not mean they are prudent. So let's take a look at some of the information in this particular article that you cited.

[The problems for the pedestrians are two-fold: "First, the additional weight means the vehicle will take longer to come to a stop and will strike with more force as compared to a lighter vehicle. Second, large vehicles have higher front ends, affecting the point of impact on a pedestrian."]

With regenerative braking on the EV, one would argue that the vehicle would actually begin to stop sooner based on the reaction time of the driver. By the time the driver becomes aware of a situation that requires braking, they would release their foot from the accelerator and then move over to the brake pedal and apply pressure onto the brake pedal to stop the vehicle. With the regenerative braking on the EV, the vehicle begins to decelerate as soon as the driver's foot is off of the accelerator which leads to a shorter braking distance due to a sooner braking initiation, which then in turns increase the chance of an accident avoidance in this particular scenario.

The higher front end point is not relevant because I am arguing about the extra weight claim. Plus if the higher front end is the culprit, then it's not about EV, it's about SUV both ICE and BEV.

The authors of these studies didn't assert a causation but instead suggest a correlation. Correlation is not a reliable indicator for cause and effect, it's simply an association.

Then there are counterargument offered by an engineer from the consumer report in the same article that you cited:

["Electric cars tend to have better weight distribution and lower centers of gravity than gas-powered cars, thanks to the ponderous battery sealed under the floor of the machine, so braking power is spread more evenly among the four wheels and the tires have more friction with the road. “It all counteracts the additional momentum,” Jake Fisher, an engineer who leads auto testing at Consumer Reports, told Bloomberg. “In a physics equation, it cancels out.”].

 

[Quiet Mini]

But you never know when you will have to take a piece of plywood with you while off roading to your office job! Seriously though, people buy way way more vehicle than they need. After 16,000 miles I have very very few cases where the Mini isn’t a perfect fit. Even if it’s your only car and you need to carry more, spend a few bucks to get a uhaul truck for an afternoon. If you need to go cross country, rent a Tesla for a weekend.

 

[Carsten Haase]

This study seems to be proving the opposite point to me:

They took a sample from a metropolitan area (shorter trips), used an assumed 3.6mi/kWh (too high for most crossovers), didn't include weather/temperature effects, and ONLY 37.9% of drivers would have been able to make all of their trips with a 140mi range EV.

Including charging would definitely make that go up but that seems very low for pretty much an ideal case for a short range EV.

They also didn't look at other external factors that effect range:

• Strap a bike, kayak, ski box, or other thing to your roof? Knock 20-50% off your range.
• Unexpected headwind on the highway? -20%
• Need to tow something? -50%

Those will be a relatively small fraction of trips but are also the ones that you'd typically be driving farther and actually need the full range. Hard to tell from their graph but looks like 150mi+ trips are ~3% (about once a month on average but would be more frequent for the majority since 37.9% don't drive very far.)

The general public doesn't want to have to think about all these details to plan trips and IMO, if you're spending tens of thousands of dollars on something it should be able to handle everything you need to do.

Quoting the "average" trip distance is also just dumb. Daily short commutes with a long trip on the weekend still averages out to a short distance. The 95th percentile value for trip distance would give a much more accurate estimate of necessary range but I've yet to see someone present that value. The study text did make this point but also didn't provide any distance statistics for the data they gathered.

There is obviously a place for short range EVs (like in my case as a 2nd car) but I'm pretty tired of all these studies claiming short range is fine without actually looking at the details of when/why that longer range is necessary.

 

[Tommm]

Please, let me get this straight:

• Smaller batteries don't have range, but "add lightness."
• Lighter cars are more nimble.
• Nimble cars are more fun to drive.
• Since the SE has a smaller battery it is lighter than other EVs. Therefore it is more nimble. That means it is more fun to drive.

Thanks Captain Obvious. It takes a clown car to point out a clown of a writer.

 

[insightman]

Please, let me get this straight:

• Smaller batteries don't have range, but "add lightness."
• Lighter cars are more nimble.
• Nimble cars are more fun to drive.
• Since the SE has a smaller battery it is lighter than other EVs. Therefore it is more nimble. That means it is more fun to drive.

Thanks Captain Obvious. It takes a clown car to point out a clown of a writer.

I may be missing the point of your post, but I believe it's the basic design of the F56 as much as the SE's "added lightness" that makes it nimble and fun to drive. A Nissan Leaf weighs about the same as an SE, but is nowhere near as much fun to drive.

 

[fishbert]

...ONLY 37.9% of drivers would have been able to make all of their trips with a 140mi range EV.

Including charging would definitely make that go up but that seems very low for pretty much an ideal case for a short range EV.
...
Quoting the "average" trip distance is also just dumb.

Hang on... you can't criticize a metric reflecting 100% of trips, then also criticize citing average trip distance.

38% might sound small at first, but that's the bar for satisfying ALL trips without making ANY adaptations; if you look at their data, even EVs with 300+ mile range only hit around 50% on that metric. So, another way of putting it could be "~80% of households whose travel needs are met by a 300-mile EV would do just as well with a smaller-battery, 140-mile EV."

They took a sample from a metropolitan area (shorter trips), used an assumed 3.6mi/kWh (too high for most crossovers)...

Of the 10 vehicles I found on ev-database.org with ~140-mile range (200-250 km) and 40kWh or smaller batteries, all of them had efficiencies listed between 3.6-4.0 mi/kWh (156-174 Wh/km), and 4 of the 10 could be considered 'crossovers' (Hyundai Kona Electric 39 kWh, Renault Megane E-Tech EV40 130hp, Kia e-Soul 39.2 kWh, and JAC iEV7s). The assumed 3.6 mi/kWh figure seem perfectly reasonable for a small-battery EV, and if "most crossovers" are less efficient than that, perhaps it's because they're heavier not-small-battery EVs.

80% of the US population lives in urban areas. Half the US population lives in metropolitan areas larger than 2 million people (think Nashville and higher). And, according to a 2013 paper cited by the study, "in terms of vehicle miles travelled, and trips per day, the people of Atlanta are slightly more reliant on personal vehicles than the American population as a whole, indicating that if there is a bias in the data used, it is a ‘conservative’ bias, producing results less favorable to the adoption of EVs."

Of course it's not going to reflect people living in rural Wyoming; it doesn't pretend to. But the sample is representative of a significant enough portion of the US population to be relevant and interesting.

 

[F14Scott]

“It’s cheaper to rent a car for two days (per year) than to spend 10 grand on a much bigger battery,” Kempton said.​

My wife and I took a southwestern national park road trip a couple of years ago. My MINI would not have made it, and her Tesla would have required a lot of thought and charging pain. We rented a new BMW SUV for the week, and we hauled a lot of stuff all over BFE Texas and New Mexico, at 90 MPH, for $500 rental and $150 in gas: 2300 miles for about $0.30 per mile.

Renting for road trips is the way to go, with or without an EV, but especially with.

 

[fishbert]

Studies may indicate otherwise: Increases in vehicle weight cause a spike in the rate of fatalities, studies show

While this is admittedly only tangentially on-topic when discussing heavier/lighter EVs, I found this new video from Not Just Bikes pretty interesting (click-baity thumbnail aside), and I assume there’s some cross-appeal with MINI owners.

 

[revorg]

Yet another reason for my rants against "trucks". Not only do they use too much carbon fuel, have too many unnecessary bright lights, and drive recklessly, but they run over little children! Oh, did I mention that people probably buy these behemoths to assuage their feelings of inadequacy? :')

 

[vader]

The old saying "horses for courses" applies here. Nobody buys a city car for road tripping - ok nobody *should* buy a cty car...... Following on, why would you drive a road trip car in the city. The obvious answer is you only have one car and compromised. From a physics point of view, the energy used to propel the car from a weight point of view (ignoring hills) is constant, proportional to weight. By this I mean it doesn't matter how fast you drive, you use X kWhs per 100 (miles/km) depending on weight. With the same tyres, a 2t car uses twice the energy of a 1t car. In town, with slow speeds, air friction is negligible in comparison to RR (rolling resistance). A light car will be more efficient than a heavy car all other things being equal. In this regard the MINI shines. Purely around town it is easy to get 10.5kWh/100km (6mi / kWh). At high speeds, air friction dominates due to its exponential nature. Double the speed, quadruple the energy used to push through the air.

Around town, you want a light weight car for efficiency. Light weight normally means light battery, hence small battery, hence low range. For city slickers, that is fine - nobody who doesn't drive for uber does 150 miles per day *in town*. As far as pedestrian safety, a light car is normally smaller, and has less chance of hitting a pedestrian. Stopping distance is determined by tyres, surface and weight distribution predominantly. The weight of the car only comes in to play if the weight transfers significantly to the front, or if the tyres can't handle the energy transfer - for example very small tyres can, for use of a better word, melt which causes skidding. Most EVs will stop in around the same distance give or take. If you are twice the size, you have a better chance of not avoiding the accident. A 500kg car hurts a person just as much as a 2000kg car. Ok, very slightly less, due to Newtons laws of conservation of momentum, but not enough to write home about.

For people (like me) who rarely go on road trips above 250km, a city car is all you need and is far better than carrying around batteries that are never needed. They are more efficient and cheaper. Small cars can avoid an accident better than a large car - the corollary is that cars with larger batteries are normally larger, so have more chance of being involved in an accident. Weight isn't a factor other than making the car larger.

 

[Carsten Haase]

Hang on... you can't criticize a metric reflecting 100% of trips, then also criticize citing average trip distance.

Why not? They both seem like relatively useless metrics to me. I agree that 100% with no adaptations is unnecessarily restrictive and not a very meaningful statistic (especially since, as you pointed out, even EVs with ICE level range can't meet the goal).

Also, I missed it the first look through but that 37.9% of households figure was assuming "intra-house substitution" aka a 2nd gas car. If you assume charging only at home and work with a single car it drops to 12.6% of households. They were also assuming people would drive down to 0% which is not exactly reasonable.

Of the 10 vehicles I found on ev-database.org with ~140-mile range (200-250 km) and 40kWh or smaller batteries, all of them had efficiencies listed between 3.6-4.0 mi/kWh (156-174 Wh/km), and 4 of the 10 could be considered 'crossovers' (Hyundai Kona Electric 39 kWh, Renault Megane E-Tech EV40 130hp, Kia e-Soul 39.2 kWh, and JAC iEV7s). The assumed 3.6 mi/kWh figure seem perfectly reasonable for a small-battery EV, and if "most crossovers" are less efficient than that, perhaps it's because they're heavier not-small-battery EVs.

That's sort of biased though because all of the small battery EVs need to be efficient to get decent range. And while I personally disagree, the general public doesn't like small, aerodynamic vehicles. Mach E, ID4, and Audi SUVs seem to be around 3.0-3.2 mi/kWh.

My main point is that efficiency is the average and the average data doesn't reflect real world needs. My MINIs long term average is 3.9mi/kWh but I frequently get around 3.0mi/kWh going slightly uphill with a breeze or with my bike on the back and multiple times a year get as bad as 2.4mi/kWh when it's cold with a headwind on the highway. Change in efficiency is completely ignored in the study but has a huge effect on the result.

Range need should be determined by the ~5% of trips that require the most energy (either due to distance or external effects or both)

 

[fishbert]

That's sort of biased though because all of the small battery EVs need to be efficient to get decent range. ... Mach E, ID4, and Audi SUVs seem to be around 3.0-3.2 mi/kWh.

Riiiiiight... small-battery EVs are more efficient because they need to be. There's no other explanation. Nope, none at all.

Ford Mach E: 4,318 - 4,838 lbs
Volkswagen ID4: 4,559 - 4,665 lbs
Audi Q4 e-tron: 4,167 - 4,707 lbs
Audi Q8 e-tron: 5,699 lbs

Hyundai Kona Electric: 3,715 - 3,836 lbs
Renault Megane E-Tech: 3,389 lbs
Kia e-Soul: 3,289 - 3,366 lbs
JAC iEV7s: 3,219 lbs
MINI Cooper SE: 3,143 lbs​

The whole point of this thread is that small-battery EVs have certain inherent advantages over large-battery EVs. It's not "sort of biased"; it's the fundamental thesis!

My MINIs long term average is 3.9mi/kWh but I frequently get around 3.0mi/kWh going slightly uphill with a breeze or with my bike on the back and multiple times a year get as bad as 2.4mi/kWh when it's cold with a headwind on the highway.

"When I drive my EV to work, it's uphill both ways in the snow!"

 

[insightman]

"When I drive my EV to work, it's uphill both ways in the snow!"

That's what my Dad used to tell me!

 

[Carsten Haase]

Riiiiiight... small-battery EVs are more efficient because they need to be. There's no other explanation. Nope, none at all.

Ford Mach E: 4,318 - 4,838 lbs
Volkswagen ID4: 4,559 - 4,665 lbs
Audi Q4 e-tron: 4,167 - 4,707 lbs
Audi Q8 e-tron: 5,699 lbs

Hyundai Kona Electric: 3,715 - 3,836 lbs
Renault Megane E-Tech: 3,389 lbs
Kia e-Soul: 3,289 - 3,366 lbs
JAC iEV7s: 3,219 lbs
MINI Cooper SE: 3,143 lbs​

Lucid air: 4,630 lb (and 3.9mi/kWh)
EV6: 4,431 lb (and 3.9 mi/kWh)
Model S: 4,784 lb (and 3.7 mi/kWh)

All just as heavy as your list but as efficient as the MINI?

There is in fact another explanation to your thesis: aerodynamics. Many heavy vehicles happen to also be larger meaning more frontal area and more drag. They're also frequently styled like a brick making their drag even worse.

The advantage of small battery EVs is cost and less wasted resources (obviously still a huge benefit). Battery size and weight have a small effect on efficiency, rolling resistance is roughly 15%-20% of total drag at highway speeds (from epa road load coefficients), and a significant fraction of that percentage is due to the drivetrain (compare the RWD vs AWD versions of the same cars).

"When I drive my EV to work, it's uphill both ways in the snow!"

Here's my round trip efficiency for the past year+. My point was not that I live in some hell where everything is uphill, it was that there is very clearly a large variance in efficiency vs the 3.9mi/kWh average. That variance requires some amount of "wasted" battery buffer to make the same trip in all conditions.