The issue with this type of motor is that it is part of the unsprung weight since it is inside the wheel. This is probably why savings here matter a lot more (or at least in a very different way) than the battery weight.
Ok, now I understand why this motor is only used in supercars - installing four (or even only two - according to https://www.mercedes-benz.de/passengercars/technology/concep..., even the AMG GT-XX has "only" three of them) hub motors with twice the power of a Tesla Model 3 in any other car would be ridiculous. So, the actual challenge is to make this motor even smaller while keeping the same power to weight ratio, so it can also be used for regular cars? That is, if they want to build something for the mass market, not only for an exclusive clientele?
I don't think their motors are axial flux, they're just large and narrow to fit inside wheels. Or at least all the images on their website depict radial flux designs.
Do e-bikes really need significantly more power than they have? They already run arguably dangerously fast for their application. Is efficiency not the primary target there?
e-bikes don't necessarily need more power but they could benefit from a smaller and lighter motor. If it becomes small enough to "disappear" in the pedal assembly for example, it would allow more design/parts commonality with normal bikes and fit more people's aesthetic criteria.
The lower weight would be definitely welcome, my ebike is comically heavy compared to a normal one and sometimes I have to carry it up flights of stairs (some German railway overpasses, grr).
Also in scooters it could fit in the wheel (since the wheel is tiny and has to spin quite quickly - no reduction gear needed vs a bike with 26-28" rims) allowing a simpler design and cost savings. But maybe in scooters they're already using in-wheel motors, I'm a bit ignorant there.
There are some advantages to hub motors in an e-bike, and if the motor and an appropriate gearing system could be made light enough the disadvantages would be reduced.
Oddly, a very large majority of current fully suspended e-bikes with rear cargo racks have those racks unsprung, which suggests that most e-bike manufacturers don’t actually care about the handling of anything other than their pure e-MTBs.
While more power may not make sense, less weight is an easy way to get more efficiency. And if you can keep the same power at a lower weight, that's a win.
Hmm. I am NOT an expert (though I ride and have owned 3 traditional motorcycles). IIUC, reducing unsprung weight is really crucial for handling -- which is why so-called "inverted" forks / front shock absorbers became basically the standard.
They don’t need this motor, but if it can be scaled down… at over 10kW/kg sustained, one could wish/hope to get 200W at 50g (disclaimer: I have no idea how this scales with size). Combine that with 1kg of a 600Wh/kg battery (https://news.ycombinator.com/item?id=45797452. Again, I have no idea how realistic that is), and you have a bicycle that’s only a little heavier than a non-electric one, but gives you a boost for 3 hours (more if you use it sparingly. If you’re cycling at leisure, 100W already is a lot of power)
Yeah, you kind of shouldn't use a Raspberry Pi to blink an LED, though. Great "Hello World" project. But there are so many ways that are cheaper, lighter, smaller and more reliable (and don't require a lengthy boot-up).
Ah not to worry we can make it a web service and host it on the cloud and of course you wouldn't want to run without a authentication so you'd need that and also a database and what if you want to blink the led securely so you'll need to use a homorphic database which is very computationally expensive so just need a couple of VMs and anyway you should start with https://www.npmjs.com/package/blinking and go from there.
From Wikipedia on Axial Flux Motors:
>"Mercedes-Benz subsidiary YASA (Yokeless and Segmented Armature) makes AFMs that have powered various concept (Jaguar C-X75), prototype, and racing vehicles. It was also used in the Koenigsegg Regera, the Ferrari SF90 Stradale and S96GTB, Lamborghini Revuelto hybrid and the Lola-Drayson.[9] The company is investigating the potential for placing motors inside wheels, given that AFM's low mass does not excessively increase a vehicle's unsprung mass.[10] "
I think they misspoke when they said "in" the wheel, but supercars can have a separate motor for each wheel, and the closer they are to the wheel the better the torque as it's not also driving a longer shaft. The smaller the motor, the closer you can get.
I guess if you can make the motor and a suitable reduction box lighter than the equivalent bearing and driveshaft combination you could make the suspension arms mechanically simpler.
By using motors at each wheel you'd eliminate the need for a differential, saving a good 40-50kg or so. Of course, if you kept the drive shafts and put the motor and reduction box in the middle, you'd be able to use inboard brakes and save a lot of unsprung weight!
There are cars with inboard brakes, although not recently. From a packaging point of view putting them out at the wheel makes sense, since there's a lot of space you're not using otherwise.
It's hard to fit inboard brakes to front wheel drive cars because there's so little space but Citroën managed it with the 2CV and various derivatives, and the GS/GSA/Birotor family. They had an inline engine with a very compact gearbox behind, with the brake discs (drums, on very early 2CVs) right on the side of the gearbox.
You got lower unsprung weight and possibly more usefully the kingpin was aligned with the centre of the tyre, so when you steered the tyre turned "on the spot" rather than rotating through a curve.
Some old Jags and Alfas had inboard discs on the rear axle, which was of course rear wheel drive. They were a bit of a pain to get at.
I’ve generally assumed that brakes are in the wheel because they’re not all that massive, they get decent cooling airflow in the wheel, and they can produce enormous amounts of torque.
it would be really interesting if it became possible to do electronic only breaks. I'm sure the regulatory system isn't there yet, but it would let you shave a whole bunch more parts and complexity
YASA doesn't call it a hub motor specifically but that's one place where it helps to save as much weight as possible. And for the cars most likely to have 1000+HP weight matters too. A Tesla motor weighs 100-200lbs, so saving that much weight down to 28lbs on a supercar is highly desirable.
I think large drones will be another place where a downsized version of this motor will make a huge difference, assuming the power scales nicely with size.
I might be wrong, but I don’t think these motors are intended to be used inside the wheel. That would add a ton of additional requirements in terms of physical durability as well as constrain optimal torque and RPM of the motor design.
I believe the Aptera was originally going to have motors in the wheels... My understanding is the the first version will forego that, as there were challenges i guess, but i think they still to eventually do that.
> This is probably why savings here matter a lot more (or at least in a very different way) than the battery weight.
Wouldn't that make it worse or just ... different. Before this the unsprung weight wouldn't have had a motor in there and now it does. Increasing the unsprung weight doesn't seem a like a good thing.
What current mass production EVs use hub motors? It seems a lot more sensible to have the motors inboard, mounted to the chassis, and drive the wheel(s) with axle shafts. It seems in my searching this is how nearly all EVs are currently designed and produced.
See also the Saab Emily GT project. Even with an older, heavier gen of these axial flux motors they found significant performance gains by controlling each wheel via its own motor.
I didn't want to put the usability of the motor into question or go into a complete evaluation of advantages/disadvantages :) This was just an explanation that weight trimming the motor might be very much worth the effort - even if it somewhat "insignificant" compared with savings that are possible in battery weight.
In-wheel application is possible, but it's important to understand that the pancake shape is only a consequence of the axial flux design and Yasa doesn't make motors in other "formats". Yasa motors shaped like this have been used in several supercars and all of them have been in-board on the axles, not in-wheel.
It compounds. If you have a lighter more efficient motor you need a smaller battery for the same range, that combined weight loss means you meed lighter brakes etc etc, and because the car is now lighter you size of your motor you need is less.....
They claim, this compounding effect works out to basically double the effective weight saving from battery and motor.
ie if you start with saving 50kg on motor, and 50kg on battery, you end up saving 200kg over all. Still only about 10% of a typical electric car.
> If you have a lighter more efficient motor you need a smaller battery for the same range
Nitpick: You can have a lighter motor, but you're never going to have a significantly more efficient motor because existing EV motor systems are already 95% efficient or better. The electric motor is an old and refined technology.
I'm not an expert - but the axial flux design while old is been largely ignored due to manufacturing problems that have now been overcome ( so most of the dev has been on the radial flux variety ).
And apparently axial flux motors have shorter magnetic flux paths which reduces losses.
ie the efficiency gain is due to the switch from radial to axial flux - not some incremental gain on radial flux.
Having said that the efficiency gains are relatively small - 1-2%.
However again there is a compounding effect, in that the reduction of loss of energy as heat, leads to requiring less cooling - and/or the motor is able to operate a full efficiency over a wider power output range ( as heating the copper increases the electrical resistance ).
Suppose you go from a 95% efficient electric motor to a 99% efficient motor. How much more efficient is it? You might say 1.04x (or actually 99/95 efficient). Except, that's not the whole story - electric motors need cooling, and you've just dropped the heat output five-fold (going from 5% heat to 1% heat). Lower heat output means less venting needed and thus better aerodynamics.
What's a bit of a shame is they are no longer an independent company ( ie wholly owned owned by Mercedes ) - so that might mean we are less likely to see these motors combined with solid state batteries any time soon.
Yea that's the thing right, the battery is so very much of the weight that optimizing the other parts are "meh" at this point. What is cool is that the 600Wh/kg solid state batteries seems like they are really finally here soon :) i.e removing 200-300kg from a car in one go will be a game changer.
Range being worse with a fully loaded car than with a lightly loaded car isn't exactly news, and not exactly limited to electric cars. I can clearly feel my old diesel struggling more when I'm driving 3 friends and with loads of heavy stuff in the back than when I'm alone. That makes the gas bill more expensive.
You probably know already, but ICE cars only convert about 20–30% of fuel energy into motion, while EVs are often +90% efficient. So when an EV has to work harder (extra battery weight or colder weather), you notice the drop in range more.
In an ICE, the same load is less visible because most energy gets wasted as heat. This is also why cold weather seems to affect EV range more.
> You probably know already, but ICE cars only convert about 20–30% of fuel energy into motion, while EVs are often +90% efficient. So when an EV has to work harder (extra battery weight or colder weather), you notice the drop in range more.
There's a kernel of truth here in that Otto engines suffer lower efficiency at part load, however I suspect the real reason is that gas car range is "good enough" and refilling is fast, so one doesn't tend to obsess about remaining range.
> This is also why cold weather seems to affect EV range more.
That's because a) some batteries suffer degraded performance at low temperature, and b) ICE cars use the plentiful waste heat for cabin heating whereas an EV needs a heat pump or even resistive heating of the cabin air.
> That's because a) some batteries suffer degraded performance at low temperature, and b) ICE cars use the plentiful waste heat for cabin heating whereas an EV needs a heat pump or even resistive heating of the cabin air.
You are making my point here actually. Combustion engines suffer from the exact same, but because they waste so much energy as heat already, less “extra” energy needs to be spent on that.
I don't think there's a contradiction here. Electric cars suffer degraded range when it's cold (in part) because they're so much more efficient that they don't produce enough waste heat to heat the cabin. And batteries are so much less energy dense than diesel and gasoline that the extra power draw reduces their range to a meaningful degree.
Yes heating impacts range in an EV, but it's not really an efficiency thing, it's because you can't get it "free". If an ICE didn't let you harness the heat, you'd see a similar percent drop in range.
And for extra weight, it's just not true. Making a motor work 10% harder at 90% efficiency, compared to making an engine work 10% harder at 20% efficiency, both of these are going to reduce your range by 9%.
The unexpected benefit which I've noticed when switching from a small, light car to a heavier, medium EV car is that the latter doesn't drive/feel any worse when fully loaded. Makes the trips that much more pleasant.
True! If only grandma wouldn't insist on bringing 250kg of weapons and ammunition with her everywhere I'd get much better range in my EV, but alas this is the USA.
Instead of technological advancements of EV motors, we can immediately use existing pharmaceutical tech (Ozempic, GLP-1) to immediately deliver weight reduction to cars. However, this will be immediately offset by the increase in weight of weapons carried, thanks to Jevons Paradox.
Manufacturers may just keep the battery size and market the improved range instead? Smaller cars in urban and suburban environments have always had lots of benefits, but since many of them are collective in nature, it has largely fallen on tragedy of the commons, and we got larger cars with larger hoods instead.
They might, but so far they don't. Manufacturers are largely switching to LFP (although to be fair they tend to offer a long-range option which ships NMC instead) and the main benefit of LFP is cost. The range of electric cars on the market is largely capped at 500KM/300miles. They could offer more, but they don't.
Not true. Tesla themselves said the way they got the Model 3 to be so efficient was by optimising every single part exhaustively. It’s expensive at design stage but results in the most efficiency gains across the fleet - so worth it (especially something like the motors)
The issue with this type of motor is that it is part of the unsprung weight since it is inside the wheel. This is probably why savings here matter a lot more (or at least in a very different way) than the battery weight.
Ok, now I understand why this motor is only used in supercars - installing four (or even only two - according to https://www.mercedes-benz.de/passengercars/technology/concep..., even the AMG GT-XX has "only" three of them) hub motors with twice the power of a Tesla Model 3 in any other car would be ridiculous. So, the actual challenge is to make this motor even smaller while keeping the same power to weight ratio, so it can also be used for regular cars? That is, if they want to build something for the mass market, not only for an exclusive clientele?
But why limit only to cars? Can this be used for motorcycles, e-bikes, electric buses, train wheels, e-unicycles, electric golf carts, etc?
There are probably a range of application where in-wheel makes perfect sense.
Donut Labs markets a whole suite of axial flux motors. Sized from scooters through to large trucks. But no public pricing.
And thrusters for boats as well, IIRC.
I don't think their motors are axial flux, they're just large and narrow to fit inside wheels. Or at least all the images on their website depict radial flux designs.
Motorcycles I could imagine.
Do e-bikes really need significantly more power than they have? They already run arguably dangerously fast for their application. Is efficiency not the primary target there?
e-bikes don't necessarily need more power but they could benefit from a smaller and lighter motor. If it becomes small enough to "disappear" in the pedal assembly for example, it would allow more design/parts commonality with normal bikes and fit more people's aesthetic criteria.
The lower weight would be definitely welcome, my ebike is comically heavy compared to a normal one and sometimes I have to carry it up flights of stairs (some German railway overpasses, grr).
Also in scooters it could fit in the wheel (since the wheel is tiny and has to spin quite quickly - no reduction gear needed vs a bike with 26-28" rims) allowing a simpler design and cost savings. But maybe in scooters they're already using in-wheel motors, I'm a bit ignorant there.
There are some advantages to hub motors in an e-bike, and if the motor and an appropriate gearing system could be made light enough the disadvantages would be reduced.
Oddly, a very large majority of current fully suspended e-bikes with rear cargo racks have those racks unsprung, which suggests that most e-bike manufacturers don’t actually care about the handling of anything other than their pure e-MTBs.
While more power may not make sense, less weight is an easy way to get more efficiency. And if you can keep the same power at a lower weight, that's a win.
Hmm. I am NOT an expert (though I ride and have owned 3 traditional motorcycles). IIUC, reducing unsprung weight is really crucial for handling -- which is why so-called "inverted" forks / front shock absorbers became basically the standard.
bicycle weight ratios are completely different from even motorcycles. a bike wheel can quickly become heavier than the frame for example.
The motor to battery weight ratio on e-bike is much more than for cars. Having a lighter motor would improve the efficiency.
They don’t need this motor, but if it can be scaled down… at over 10kW/kg sustained, one could wish/hope to get 200W at 50g (disclaimer: I have no idea how this scales with size). Combine that with 1kg of a 600Wh/kg battery (https://news.ycombinator.com/item?id=45797452. Again, I have no idea how realistic that is), and you have a bicycle that’s only a little heavier than a non-electric one, but gives you a boost for 3 hours (more if you use it sparingly. If you’re cycling at leisure, 100W already is a lot of power)
For reference, an average commuter cyclist has a power output of about 200W, a world-class racer can do about 600W.
Ref: https://www.cyclinganalytics.com/blog/2018/06/how-does-your-...
Yes, all else equal, we want lighter motors in vehicles.
I'm always interested to hear about the latest in lighter and possibly more powerful and torque-y e-bike motors.
If engine can be produced cheaply, can it be limited "in software"? It's like saying people shouldn't use Rasberry Pi to blink an LED.
Yeah, you kind of shouldn't use a Raspberry Pi to blink an LED, though. Great "Hello World" project. But there are so many ways that are cheaper, lighter, smaller and more reliable (and don't require a lengthy boot-up).
Ah not to worry we can make it a web service and host it on the cloud and of course you wouldn't want to run without a authentication so you'd need that and also a database and what if you want to blink the led securely so you'll need to use a homorphic database which is very computationally expensive so just need a couple of VMs and anyway you should start with https://www.npmjs.com/package/blinking and go from there.
Yeah, my first thought was racing EUC’s, lol….
End User Credentials ? Everyone Uses Cars ? Engineered Universal Conscience? (Since you seem to assume we all share your thoughts & context...)
E-UniCycles are mentioned in gp. It’s a common initialism for them.
Electric UniCycles
I don’t see anything inside the article that says it’s designed to be inside the wheel. I’m not sure where they got that from.
From Wikipedia on Axial Flux Motors: >"Mercedes-Benz subsidiary YASA (Yokeless and Segmented Armature) makes AFMs that have powered various concept (Jaguar C-X75), prototype, and racing vehicles. It was also used in the Koenigsegg Regera, the Ferrari SF90 Stradale and S96GTB, Lamborghini Revuelto hybrid and the Lola-Drayson.[9] The company is investigating the potential for placing motors inside wheels, given that AFM's low mass does not excessively increase a vehicle's unsprung mass.[10] "
The fact that you CAN put it in the wheel doesn't mean it MUST to go in the wheel.
Yes but the wikipedia article is referencing YASA, the company in the featured article.
They’re investigating the potential for them to be placed inside wheels, but they aren’t at the moment, so my point stands.
I think they misspoke when they said "in" the wheel, but supercars can have a separate motor for each wheel, and the closer they are to the wheel the better the torque as it's not also driving a longer shaft. The smaller the motor, the closer you can get.
I guess if you can make the motor and a suitable reduction box lighter than the equivalent bearing and driveshaft combination you could make the suspension arms mechanically simpler.
By using motors at each wheel you'd eliminate the need for a differential, saving a good 40-50kg or so. Of course, if you kept the drive shafts and put the motor and reduction box in the middle, you'd be able to use inboard brakes and save a lot of unsprung weight!
I wonder if that would be legal, or if there is a regulation about where you can put your brakes?
There are cars with inboard brakes, although not recently. From a packaging point of view putting them out at the wheel makes sense, since there's a lot of space you're not using otherwise.
It's hard to fit inboard brakes to front wheel drive cars because there's so little space but Citroën managed it with the 2CV and various derivatives, and the GS/GSA/Birotor family. They had an inline engine with a very compact gearbox behind, with the brake discs (drums, on very early 2CVs) right on the side of the gearbox.
You got lower unsprung weight and possibly more usefully the kingpin was aligned with the centre of the tyre, so when you steered the tyre turned "on the spot" rather than rotating through a curve.
Some old Jags and Alfas had inboard discs on the rear axle, which was of course rear wheel drive. They were a bit of a pain to get at.
Super pro comment, should be much higher.
I’ve generally assumed that brakes are in the wheel because they’re not all that massive, they get decent cooling airflow in the wheel, and they can produce enormous amounts of torque.
it would be really interesting if it became possible to do electronic only breaks. I'm sure the regulatory system isn't there yet, but it would let you shave a whole bunch more parts and complexity
Interesting! But yes in axel in this case then
I get your skepticism and I know nothing about the field, but if the round thing in the press release picture isn’t designed to fit in a wheel, I’m confused. https://yasa.com/news/yasa-smashes-own-unofficial-power-dens...
Not necessarily, cf: https://lammotor.com/wp-content/uploads/2024/12/YASA-400R.jp...
From https://lammotor.com/yasa-axial-flux-motor/
the shape is due to the change to the motor layout: https://www.thedrive.com/news/why-axial-flux-motors-are-a-bi...
It’s currently designed for the axel for now as far as I’m aware.
Well, Tesla also started with the higher end of the market. That's where people are willing to pay more.
YASA doesn't call it a hub motor specifically but that's one place where it helps to save as much weight as possible. And for the cars most likely to have 1000+HP weight matters too. A Tesla motor weighs 100-200lbs, so saving that much weight down to 28lbs on a supercar is highly desirable.
I think large drones will be another place where a downsized version of this motor will make a huge difference, assuming the power scales nicely with size.
I might be wrong, but I don’t think these motors are intended to be used inside the wheel. That would add a ton of additional requirements in terms of physical durability as well as constrain optimal torque and RPM of the motor design.
I believe the Aptera was originally going to have motors in the wheels... My understanding is the the first version will forego that, as there were challenges i guess, but i think they still to eventually do that.
Why would it have to be unsprung? They are not unsprung in the vehicle shown in the article.
> This is probably why savings here matter a lot more (or at least in a very different way) than the battery weight.
Wouldn't that make it worse or just ... different. Before this the unsprung weight wouldn't have had a motor in there and now it does. Increasing the unsprung weight doesn't seem a like a good thing.
What current mass production EVs use hub motors? It seems a lot more sensible to have the motors inboard, mounted to the chassis, and drive the wheel(s) with axle shafts. It seems in my searching this is how nearly all EVs are currently designed and produced.
I believe caring about unsprung weight only matters for handling not efficiency
See also the Saab Emily GT project. Even with an older, heavier gen of these axial flux motors they found significant performance gains by controlling each wheel via its own motor.
https://electrek.co/2023/04/27/saab-engineers-develop-secret...
I didn't want to put the usability of the motor into question or go into a complete evaluation of advantages/disadvantages :) This was just an explanation that weight trimming the motor might be very much worth the effort - even if it somewhat "insignificant" compared with savings that are possible in battery weight.
Where does it say it’s inside the wheel? Not sure about that
He’s holding the motor in the picture. That format is in-wheel BLDC.
In-wheel application is possible, but it's important to understand that the pancake shape is only a consequence of the axial flux design and Yasa doesn't make motors in other "formats". Yasa motors shaped like this have been used in several supercars and all of them have been in-board on the axles, not in-wheel.
That format is the standard format for axial flux motors...
I don’t believe it is in this case.
It compounds. If you have a lighter more efficient motor you need a smaller battery for the same range, that combined weight loss means you meed lighter brakes etc etc, and because the car is now lighter you size of your motor you need is less.....
They claim, this compounding effect works out to basically double the effective weight saving from battery and motor.
ie if you start with saving 50kg on motor, and 50kg on battery, you end up saving 200kg over all. Still only about 10% of a typical electric car.
https://youtu.be/3qjB6GnhloY?si=yqlz7Evuyf5VaghO&t=446
> If you have a lighter more efficient motor you need a smaller battery for the same range
Nitpick: You can have a lighter motor, but you're never going to have a significantly more efficient motor because existing EV motor systems are already 95% efficient or better. The electric motor is an old and refined technology.
I'm not an expert - but the axial flux design while old is been largely ignored due to manufacturing problems that have now been overcome ( so most of the dev has been on the radial flux variety ).
And apparently axial flux motors have shorter magnetic flux paths which reduces losses.
ie the efficiency gain is due to the switch from radial to axial flux - not some incremental gain on radial flux.
Having said that the efficiency gains are relatively small - 1-2%.
However again there is a compounding effect, in that the reduction of loss of energy as heat, leads to requiring less cooling - and/or the motor is able to operate a full efficiency over a wider power output range ( as heating the copper increases the electrical resistance ).
https://www.stanfordmagnets.com/advantages-and-disadvantages...
Suppose you go from a 95% efficient electric motor to a 99% efficient motor. How much more efficient is it? You might say 1.04x (or actually 99/95 efficient). Except, that's not the whole story - electric motors need cooling, and you've just dropped the heat output five-fold (going from 5% heat to 1% heat). Lower heat output means less venting needed and thus better aerodynamics.
What's a bit of a shame is they are no longer an independent company ( ie wholly owned owned by Mercedes ) - so that might mean we are less likely to see these motors combined with solid state batteries any time soon.
https://en.wikipedia.org/wiki/Tsiolkovsky_rocket_equation
Yea that's the thing right, the battery is so very much of the weight that optimizing the other parts are "meh" at this point. What is cool is that the 600Wh/kg solid state batteries seems like they are really finally here soon :) i.e removing 200-300kg from a car in one go will be a game changer.
No wonder electrics don't sell well in the US. People weigh more, you're basically saying that leaving grandma at home, is a "game changer".
>> removing 200-300kg from a car in one go will be a game changer
> No wonder electrics don't sell well in the US. People weigh more, you're basically saying that leaving grandma at home, is a "game changer".
Even in the US, your average grandma weighs less than 2-300kg :D
[This post to prevent ulterior posting of "yo mama" jokes]
Range being worse with a fully loaded car than with a lightly loaded car isn't exactly news, and not exactly limited to electric cars. I can clearly feel my old diesel struggling more when I'm driving 3 friends and with loads of heavy stuff in the back than when I'm alone. That makes the gas bill more expensive.
You probably know already, but ICE cars only convert about 20–30% of fuel energy into motion, while EVs are often +90% efficient. So when an EV has to work harder (extra battery weight or colder weather), you notice the drop in range more.
In an ICE, the same load is less visible because most energy gets wasted as heat. This is also why cold weather seems to affect EV range more.
> You probably know already, but ICE cars only convert about 20–30% of fuel energy into motion, while EVs are often +90% efficient. So when an EV has to work harder (extra battery weight or colder weather), you notice the drop in range more.
There's a kernel of truth here in that Otto engines suffer lower efficiency at part load, however I suspect the real reason is that gas car range is "good enough" and refilling is fast, so one doesn't tend to obsess about remaining range.
> This is also why cold weather seems to affect EV range more.
That's because a) some batteries suffer degraded performance at low temperature, and b) ICE cars use the plentiful waste heat for cabin heating whereas an EV needs a heat pump or even resistive heating of the cabin air.
> That's because a) some batteries suffer degraded performance at low temperature, and b) ICE cars use the plentiful waste heat for cabin heating whereas an EV needs a heat pump or even resistive heating of the cabin air.
You are making my point here actually. Combustion engines suffer from the exact same, but because they waste so much energy as heat already, less “extra” energy needs to be spent on that.
I don't think there's a contradiction here. Electric cars suffer degraded range when it's cold (in part) because they're so much more efficient that they don't produce enough waste heat to heat the cabin. And batteries are so much less energy dense than diesel and gasoline that the extra power draw reduces their range to a meaningful degree.
Part of your point is right, part is wrong.
Yes heating impacts range in an EV, but it's not really an efficiency thing, it's because you can't get it "free". If an ICE didn't let you harness the heat, you'd see a similar percent drop in range.
And for extra weight, it's just not true. Making a motor work 10% harder at 90% efficiency, compared to making an engine work 10% harder at 20% efficiency, both of these are going to reduce your range by 9%.
The unexpected benefit which I've noticed when switching from a small, light car to a heavier, medium EV car is that the latter doesn't drive/feel any worse when fully loaded. Makes the trips that much more pleasant.
That's true only if your very large "grandma" must at all cost sit on your batteries at all times.
If we could indeed leave "grandma" home, that would make things better.
And they don't sell well in the US because of oil lobbying and think tanks whose sole goal is to make you buy more oil.
Well, the world's most popular electric car brand (BYD) is also virtually banned in the US. That doesn't help with adoption.
True! If only grandma wouldn't insist on bringing 250kg of weapons and ammunition with her everywhere I'd get much better range in my EV, but alas this is the USA.
250kg grandma = ~20 small dogs
250kg weapons = ~20 small dogs
Instead of technological advancements of EV motors, we can immediately use existing pharmaceutical tech (Ozempic, GLP-1) to immediately deliver weight reduction to cars. However, this will be immediately offset by the increase in weight of weapons carried, thanks to Jevons Paradox.
Quite frankly I would like to hang out with that grandma. Load it up, I’ll take the range hit.
Manufacturers may just keep the battery size and market the improved range instead? Smaller cars in urban and suburban environments have always had lots of benefits, but since many of them are collective in nature, it has largely fallen on tragedy of the commons, and we got larger cars with larger hoods instead.
They might, but so far they don't. Manufacturers are largely switching to LFP (although to be fair they tend to offer a long-range option which ships NMC instead) and the main benefit of LFP is cost. The range of electric cars on the market is largely capped at 500KM/300miles. They could offer more, but they don't.
Why not both? For a two-car family, having a good road-tripper and a light sporty car can work out pretty nicely.
Not true. Tesla themselves said the way they got the Model 3 to be so efficient was by optimising every single part exhaustively. It’s expensive at design stage but results in the most efficiency gains across the fleet - so worth it (especially something like the motors)