How Polestar engineers EVs that can handle brutal winters
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What do you mean by a "brushless DC motor"?
Basically what most people mean is a synchronous motor in which the field windings are driven by a current that only goes one way (DC) rather than an alternating current. It's easier and cheaper to design a DC synchronous motor drive, but EMI is more of a problem and the torque irregularity is not so good for reduction gears.
Exactly the same rules apply as with an AC synchronous motor, apply a DC to the coils and it will just sit there getting hot.
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Oh really? I hadn't heard anything about more delays. Sad.
Edit: This is the closest thing I could find easily to real info. https://www.topspeed.com/rivian-r3-production-launch-date/
Sigh.
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LordSlinkySupreme
Smack-Fu Master, in training
Denver doesn't get nearly as much snow as Minnesota, but I will say my Polestar 2 handled winter like a goddamn champ. Unbelievable traction and fine motor control on ice and snow with all-season tires, no less.I'm inherently going to trust any EV tested in Sweden by Swedes for cold weather performance where I live; Northern Minnesota is a lot like being in Västerås. Anything tested to -50 and driven by people who live there is a great sign.
... Anyone know if Rivian is shipping their equipment up north for testing?
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LordSlinkySupreme
Smack-Fu Master, in training
Having recently driven a Highland refresh Model 3, it has heavy steering, but almost no road feel, so I'm not quite sure what you're quantifying as "road feel."
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An M3 is a BMW. Tesla makes a Model 3. And Polestar doesn't build a P3.
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Sigh. You should spend more time on the internet. There are a lot of people using the term interchangably.
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Haven't driven one of those, so can't comment. A 2020 M3 (just to out-snark Snark218) doesn't have great feedback through the steering wheel but there is some. You can certainly feel the thing slide. There's also any sensations transmitted through the suspension, then through the seat to the driver.
The air suspension on the P3 removes even that. Only sensation I got through the wheel and the seat was it trying not to lean around corners and failing.
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(sigh). Please remember units: miles/kWh at the very least. Tho' I find it more helpful to measure usage, i.e. Wh/mile (or per km).
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I looked it up and Rivian claims to do testing in Minnesota.I'm inherently going to trust any EV tested in Sweden by Swedes for cold weather performance where I live; Northern Minnesota is a lot like being in Västerås. Anything tested to -50 and driven by people who live there is a great sign.
... Anyone know if Rivian is shipping their equipment up north for testing?
"In extremely cold conditions we use some battery energy to keep the cells in our battery above 14°F to provide controlled vehicle performance. Some EVs have electrical heaters to heat the battery up, which is another component — more cost, more mass and a drain on electrical supply. Instead, we’re using our inverter and motor to generate heat — even while stationary our traction system can generate substantial heat for the battery. And we use that heat to warm the battery to the point where it can deliver full performance. Our battery is uniquely designed to operate in super cold conditions, all the way down to an ambient temp of -40°F."
As an aside - speaking of battery performance in cold weather, I have noticed that a lot of anti-EV seem to claim EV don't work in "proper cold weather" in the US. I recently found a climate zone map of the US for that shows the minimum lows in an area (for plants you can plant that won't die in the winter so the minimums matter). To be sure there are cold places in the US, but nowhere the proportion of US population that people claim.
Here's a map of population density which is basically the reverse of the truly cold (under -10F) areas in the map above. So battery capacity will be reduced, but it BEV will still be usable cold weather and range still workable in "most situations" for people across the US.
Which makes sense as people in Canada own EVs as well.
And to anyone that questions the Canada BEV on the road percentage being distorted by higher PHEV, that's not true either.
Also obviously there are EV buyers in other Arctic countries - even though as some people will claim "it's not really that cold in Iceland, Sweden, Norway because the gulf effect warms the southern coast" I will present do you Finland, which doesn't have that warm southern coastal cities like Iceland, Sweden and Norway.
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I personally have no trouble parsing Tesla M3.
If you just write M3 on its own though? That's a BMW. It's been a thing for nearly 40 years, and that's what it's actually called, not a shorthand.
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This isn't up for popular vote. I understand that a lot of people who don't actually care about cars except insofar as they were enthusiastic about Tesla and Elon got into the habit of calling the Model 3 that. To anybody with even a distant enthusiasm about cars, an M3 is a BMW, and that is the actual name of the model, and BMW was building the M3 long fucking time before a bunch of Tesla stans decided typing "Model" took too long. And you're gonna get called out on that if you keep doing it, because names and words mean things.
Yeah, ever since BMW switched to electric power steering for the G20 generation, that feedback just isn't the same.
You aren't out-snarking me. You can whine about being corrected, but you're not correct. It's not that big a deal to swallow your pride, say "ok," and call the Model 3 a Model 3.
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Just to be a little contrarian:
Average temperature doesn't matter as much as minimum temperature (or "likely minimum temperature when one is likely to be driving"), though they correlate. You want your car to work always, not just on the average.
Most people live in cities, where driving is less critical anyway (though often necessary), and breakdowns are easier to deal with. If you live in a rural place and are miles from town, a reliable car is a more overwhelming concern. Satisfy that minority, and you've satisfied everybody.
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How was the build quality on the Lucid? I test drove an early one and the exterior build quality was not good, particularly around the trunk and frunk alignment. Interior quality on the other hand was quite nice save for the infotainment but they were really trying to get their legs under them then. I felt a bit bad for the sales dude because it took about five minutes to get the thing to unlock. I'm hoping to get down to test drive a Grand Touring in the next few weeks and see how much they've improved.
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You are replacing your wife with a Chrysler 200? That's pretty hardcore automotive activity.
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Some Teslas (perhaps all) do not have sufficient front wheel clearance to allow for chains. But driving in snowy conditions does not matter to Musk, since he removed the RADAR from all Teslas.
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Right and that map is the minimum temperature in that area, taken over several years and averaged - because you want you plants to survive the winter you need to know what the coldest it will ever get there so they survive the winter.
Sure, but I guess that less than 10% of the population lives more than 10 miles from the closest town of at least 500 people (i.e. someone who can come help in say 30 minutes). We aren't taking about that highway in Western Australia (Canning Stock Route?) where you can die from dehydration if you car breaks down as there are so few other vehicles passing by. Those people shouldn't use an EV any time soon and so stick with HEV and PHEV - but they a small exception (note I'm not saying PHEV should only be for those people, there are a lot of other situations with an HEV/PHEV is more practical at this time and the near future - as in the next 5-15 years).
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While your coverage of AC motors is correct, it is not accurate about DC motors. Wound field DC motors will try to "rev to the moon" as the field winding current as reduced to zero, but under normal conditions, including with PM DC motors, they will only rev to where the back EMF matches the supply voltage (minus any inherent friction, viscous lubricant, and windage torque losses).
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Having driven the polestar 2, this car is filled with problems after problems. Design issues, cramped seating, awkward cupholders, software issues, battery drain issues. All those issues have never been addressed. Polestar is the last car maker I would ever consider and EV in general. Too much hassle to deal with having to baby the battery to make sure you only charge to 80 percent, while it can't be too cold or too hot.
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Many brushless DC motors are actually driven by pulsating multiphase DC, so they are actually a type of AC motor where instead of alternating the current, it is switching a single polarity on multiple phase windings. There are also alternating current DC motors as well (think of bipolar steppers as just one example).
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I've read that the radar on Tesla also stop working when snow accumulated on the front fascia.
This isn't really an issue imo. Teslas are all RWD or AWD. So either you are RWD and need the chains in the back (I once had a who came to Lake Tahoe with a Toyota Pre-runner but the Caltrain crew installed them on his front tires and he spun out by the Carson Pass and I had to pull him out)... or you are AWD and you should have all-weather tires (I like the Michelin Cross-Climate 2 myself).
YMMV, I've driving for decades in heavy snow and I've never heard of a US road being R3 which is where even AWD vehicle with snow tires need chains without the road simply being closed because too many people are spinning out on their AWD/4WD vehicle with summer/all-season tires anyway.
At worse... I personally would just get snow-socks for the front for the very rare emergency situation (even if wheel clearance isn't an issue).
They pack much smaller and after years of putting on chains, and from what I can see they are way easier to put on and takeoff than chains (as I discover And after the mistake of owning a 2WD Honda Civic for a few years in snowy area - I later switched to the Subaru pictured above)
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You are writing about brushed motors, this was about "brushless" motors. Brushed motors are not normally used in EVs.
https://www.motioncontroltips.com/what-are-wound-field-motors-and-where-are-they-applied/
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Please, please do not abbreviate miles as “m” because that’s already used for meters, another distance unit. So you wrote that you can only travel 3.6 meters (11.8 feet) per kilowatt (which is also wrong). The correct units are miles per kilowatt-hour (mi/kWh).
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It's a shame that the Union was not the side with the national anthem that sounds best when played on the car horn.
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I looked it up and Rivian claims to do testing in Minnesota.
"In extremely cold conditions we use some battery energy to keep the cells in our battery above 14°F to provide controlled vehicle performance. Some EVs have electrical heaters to heat the battery up, which is another component — more cost, more mass and a drain on electrical supply. Instead, we’re using our inverter and motor to generate heat — even while stationary our traction system can generate substantial heat for the battery. And we use that heat to warm the battery to the point where it can deliver full performance. Our battery is uniquely designed to operate in super cold conditions, all the way down to an ambient temp of -40°F."
As an aside - speaking of battery performance in cold weather, I have noticed that a lot of anti-EV seem to claim EV don't work in "proper cold weather" in the US. I recently found a climate zone map of the US for that shows the minimum lows in an area (for plants you can plant that won't die in the winter so the minimums matter). To be sure there are cold places in the US, but nowhere the proportion of US population that people claim.
No
Here's a map of population density which is basically the reverse of the truly cold (under -10F) areas in the map above. So battery capacity will be reduced, but it BEV will still be usable cold weather and range still workable in "most situations" for people across the US.
View attachment 105929
Which makes sense as people in Canada own EVs as well.
And to anyone that questions the Canada BEV on the road percentage being distorted by higher PHEV, that's not true either.
Also obviously there are EV buyers in other Arctic countries as some people will claim "it's not really that cold in Iceland, Sweden, Norway because the gulf effect warms the southern coast"
The Nordic countries and Iceland are warm by Canadian standards. The inland far north is cold but most of them is warm (in winter; summers are cool). I am originally from north of Minnesota and now live further east where it is warm but still much colder than Norway or Sweden. Living in a city, with a garage, is sufficient for EVs though. Most driving is just commuting. There are a fair number of EVs in my neighborhood, parked outdoors to charge. They do ok.
Living in rural areas would be more of an issue.
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Yes you are repeating exactly what I said people will say that "it's not really that cold in Iceland, Sweden, Norway because the gulf effect warms the southern coast"
Hence my last examples was from Finland, which doesn't get the warm gulf waters like the south coastal cities of Norway and Sweden and that is an Arctic country that doesn't get that effect.
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For better or worse, many English-based publishing platform don't allow for diacritical marks. I know the publishing system we wrote at our small company back in 2005 blocked all non-ASCII characters for security/aesthetic (we wanted to either blocked visual spoofing of banned words from user posts and/or avoid character escaping and injection attacks we wanted in-house/freelance writers to avoid copy and pasting content that wouldn't render properly). I'm sure more skilled, talent engineers could have done a better job, but we were a small team of like 5-6 engineers it was one of many tasks that we had to do at the time.
We later expanded the system to allow for unicode latin character for publishing content in Spanish. I see that the SFGate has a similar limitation and hence a recent article had this disclaimer
"Editor’s note: SFGATE recognizes the importance of diacritical marks in the Hawaiian language. We are unable to use them due to the limitations of our publishing platform."
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Ars, when you say 'about a meter' why then translate that to 39.3 inches bananas?? Why not say 'about a meter (roughly 40 bananas)'.
No point using approximate values for metric then precise conversions to bananas when you may as well round the bananas as well.
No point using approximate values for metric then precise conversions to bananas when you may as well round the bananas as well.
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I see this so often, especially with temperature conversions.
The funniest one I saw recently was where the original had a temperature of 100 kelvins. The author converted this to -173 Celsius and then converted that to an exact temperature in Fahrenheit.
Now a confession. I once had an absolutely useless, very pedantic manager for whom nothing was ever good enough. So when I submitted a report, I would include a couple of over-precise numbers. He would spot this and draw attention to them, I would apologise and round them off. He felt he was doing his job, and I didn't have him trying to find something to complain about and getting resentful if he couldn't find it.
I'm English, but someone I mentioned it to immediately asked "Are you Swiss?"
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You mean on top of the reasons the cyber truck can't be driven when it isn't snowing?
I have a model Y Performance (from the before-times) and live in the northeast, and it handles snow well as a AWD, although I have summer and winter wheels/tires and my local mobile tire place warehouses the other pair for the season. That made a huge difference, but clearly the people who designed it never dealt with a new England winter, I'm sure they went, like this, to some winter proving ground and drove on an ice track, which is one problem to solve, but simple things like slush was not worried about. On our ski trips up north we frequently end up driving north during a snow storm, and of course the road is completely covered so your tires are kicking up enormous amount of snow in a rooster tail. Now in every car before my tesla a set of mud flaps made that a non-issue, but these guys clearly never tested that scenario. I have the mudflats on all 4 fenders but the aero of the car sucks all that back to the rear of the car, such that the back is coated with an inch of packed slush, which is a serious problem when we A) have someone behind us as the taillights are almost invisible and B) the rear camera is blocked, so when we pull into the supercharger at the halfway point, there is no way to back up, the rear facing mirror on the window (it provides no rear view so can't call it that) being utter garbage means you need to stop, get out wipe the back of the car to expose the camera then back into charge (which the same design idiot never had to do while the plows are out and have packed a snowbank in front of the charger, and oh the super-short charging cable can barely reach so you have to bury the delicate rear bumper into the snowbank to be able to charge. Then there is the heated zone for the wipers. I mean it makes a 3-4% difference in ice on the wiper, but just having the defroster blowing extra hard in a small zone doesn't cut it in heavy wet new england snow. And of course like most cars they don't heat the washer fluid so you get if you are lucky 1 wash before that is frozen solid. That pontiac system where the liquid came out steaming hot was pretty cool, since it both deiced the wipers and the window would be great (not like electricity isn't plentiful in an EV!) All these winter wonderland arctic proving grounds are great for commercials but drive in an suburban new england winter Noreaster if you want to check your car systems' capabilities.
The only thing it gets right (well in fairness the stability control works well) is that when we finally manage to begin charging as the snow is raging outside, we go into the rest stop to one of our favorite restaurants and get their fig-brie grilled cheese and put the fireplace on the dash, and eat that gooey goodness with the crackling fire. Super romantic (hey after 33 years you take what you get).
But as consumer's report has always stated in their testing, snow tires (non-studded) are critical below 40F (4.4C) as the rubber in regular tires, even "all-season" (suboptimal all the time) don't grip, which the W-rated Blizzaks I have take care of. Additionally I do a minus-one conversion between the wheels getting me an extra inch of sidewall, as the other thing designers in LA don't worry about are new england pot holes, which will bend a wheel on those summer ultra-teeny sidewalls. For the article studs are great if you're on an ice track, but in the real world not a great compromise around town as on dry pavement the studs compromise traction and likely eat milage as well. Siped soft winter rubber is king there, and so far at 35,000mi on my winter tires they show virtually no wear. It is interesting when I got my Y the manual stated under no circumstances were chains to be used, and now they have 1st party chains for the Y.
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Metres are better.
The unit km/kWH can rather neatly be reduced to m/WH. Since a watt hour is 3600j, a car doing 6km/kWH is using 600J/m, a unit I can get my head around. It's actually still a horrifying amount of energy consumed for not much actual transport.
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I would assume that was a "Model 3" shortened to "M 3" but without the space?
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It's always interesting reading this stuff. Why, this winter in East London the temperature went down to -3C for several hours one night and we might even get a few cm of snow one day. Hazardous stuff. EV territory, in fact.
What I took away from your post was "If you need to drive in snow don't buy a Tesla." Having magic tyres doesn't help if you can't see out the back and nobody can see your rear lights.
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Normal body temperature in the U.S. is 98.6 F because the rest of the world figures it is around 36.5 C and rounds it to 37 C in public health communications.
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Snow tires are mandatory in Quebec where I live, on all cars, so the part you highlighted is nothing specific to Tesla. Everything else in the post is stuff I can confirm: Tesla doesn’t know much about weather other than what occurs in Fremont, California.
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The good: polestar 4 looks much better than the 2 it replaces; Engineers have done great work ensuring it perform well in winter.
The bad: Does the 4 still the (unnecessary) rear center hump for the gas era "AWD transmission shaft"?
The ugly: When can polestar break free from the Volvo dealerships in the US?
The bad: Does the 4 still the (unnecessary) rear center hump for the gas era "AWD transmission shaft"?
The ugly: When can polestar break free from the Volvo dealerships in the US?
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Mentioning Australia, home to more venomous snakes than the USA's Republican party, made me wonder if BEVs are easier to snake-proof? The web is full of videos of people in Australia and the southern USA popping their ICE hood to expose snakes. And occasionally there are snakes in the passenger compartment.
I've driven a couple of Tesla Model S's but that only exposes me to the passenger compartment - I have no idea what things are like underneath. What holes, nooks, and crannies do ICE vehicles have that BEVs can do away with?
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I once drove a borrowed Model S from Moose Jaw to Saskatoon and back. On the way there I drove into an 80 kph headwind. After my 1.5 hour long appointment I drove to a place where I could charge up for 3 hours then headed home ... by which time the wind had changed direction so I was driving into a strong headwind again.
When I returned the car the owner checked how many km I had driven and how much juice I had used then said, "So it was uphill both ways?"
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