How Tesla Improves the Range of Its Electric Cars (caranddriver.com) 67
Car and Driver magazine explores what gives Tesla's vehicles their comparatively long range. And apparently one factor is just "big batteries.
This may be obvious, but a battery that holds more energy should translate to more range, and Tesla has the largest battery packs out there... What isn't always obvious is how much of a battery pack's energy is usable versus its maximum theoretical or gross capacity... Based on the limited data we have, it seems that Tesla allows its cars to use more of a pack's capacity than other manufacturers do. We suspect that's partially because the company puts some of the responsibility on the driver to choose how high to charge the battery, noting that anything above a 90 percent charge should be reserved only for trips, not everyday use.
Tesla's largest battery pack carries the energy equivalent of just 2.9 gallons of gas when fully charged. The key to extending EPA range is to use less electricity to propel the vehicle and to recapture as much energy as possible using the electric motors to slow the vehicle whenever the driver lifts off the accelerator during the EPA cycles' many slowdowns. Tesla's aggressive regenerative braking alone nets it a 13 percent gain in range versus the Porsche Taycan, which waits until the driver presses the brake pedal before initiating meaningful regen. This is one piece of Tesla's holistic approach to efficiency that also includes its vehicles' ability to roll down the road with less friction than their competitors.
Tesla also obtained more efficiency through the engineering of its all-wheel-drive. But there's also another interesting wrinkle: [T]he EPA allows automakers the option to run three additional drive cycles and use those results to earn a more favorable adjustment factor. Currently, only Tesla and Audi employ this strategy for their EVs, and Tesla scores the most advantageous results, with adjustments that range from 29.5 percent on the Model 3 Standard Range Plus to 24.4 percent on the Model Y Performance. If Tesla had used the standard adjustment factor of 30 percent, the Model Y Performance's window-sticker range would drop to 292 miles. But because Tesla takes advantage of the EPA's alternate methodology, the company can instead claim a 315-mile range. This is all within the regulatory rules. Among EV makers, Tesla has been at this game longer than most, so it's not surprising that it has figured out the tricks to maximizing its EPA numbers.
And the magazine shares this tip for prospective Tesla customers. "Based on the road-load data it has submitted to the EPA, opting for 21-inch wheels on a Model S Long Range Plus will cut the range by nearly 80 miles.
Tesla's largest battery pack carries the energy equivalent of just 2.9 gallons of gas when fully charged. The key to extending EPA range is to use less electricity to propel the vehicle and to recapture as much energy as possible using the electric motors to slow the vehicle whenever the driver lifts off the accelerator during the EPA cycles' many slowdowns. Tesla's aggressive regenerative braking alone nets it a 13 percent gain in range versus the Porsche Taycan, which waits until the driver presses the brake pedal before initiating meaningful regen. This is one piece of Tesla's holistic approach to efficiency that also includes its vehicles' ability to roll down the road with less friction than their competitors.
Tesla also obtained more efficiency through the engineering of its all-wheel-drive. But there's also another interesting wrinkle: [T]he EPA allows automakers the option to run three additional drive cycles and use those results to earn a more favorable adjustment factor. Currently, only Tesla and Audi employ this strategy for their EVs, and Tesla scores the most advantageous results, with adjustments that range from 29.5 percent on the Model 3 Standard Range Plus to 24.4 percent on the Model Y Performance. If Tesla had used the standard adjustment factor of 30 percent, the Model Y Performance's window-sticker range would drop to 292 miles. But because Tesla takes advantage of the EPA's alternate methodology, the company can instead claim a 315-mile range. This is all within the regulatory rules. Among EV makers, Tesla has been at this game longer than most, so it's not surprising that it has figured out the tricks to maximizing its EPA numbers.
And the magazine shares this tip for prospective Tesla customers. "Based on the road-load data it has submitted to the EPA, opting for 21-inch wheels on a Model S Long Range Plus will cut the range by nearly 80 miles.
Bunk headline (Score:5, Informative)
That’s not really about how Tesla improves it’s range - the summary is about how Tesla improves it’s EPA-rated range.
As a (happy) Tesla owner, I can tell you that the two are different things. But Slashdot editors being what they are... I shouldn’t expect accurate headlines.
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Re:Bunk headline (Score:4, Informative)
You excluded the first part of that sentence in your quote:
The key to extending EPA range is to use less electricty to propel...
So even this sentence is explicitly about getting a higher EPA rating. There are specific things that can be done to increase it which won't necessarily translate to IRL performance. E.g. coasting might acually be better because you're just using your kinetic energy to keep moving instead of losing some of it on charging the battery and then discharging it.
Plus there are also other aspects to it, like using different correction factors and not voluntarily reducing the EPA rating (on the MS) like they do on the M3 LR or like how Porsche does. There's an Engineering Explained video that goes over it here: https://www.youtube.com/watch?... [youtube.com]
tl;dr: in a highway test the Taycan and MSP get basically identical range even though the Tesla is rated at 128 extra miles.
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E.g. coasting might acually be better because you're just using your kinetic energy to keep moving
This is common knowledge for anyone who knows how to drive a car. Assuming I don't get behind someone who insists on braking while going down the rolling hills in my area because they don't want go one mile over the speed limit, I routinely coast down the hill then apply gentle pedal pressure on the other side. It's one of many reasons my fuel mileage is always better than what the manufacturer says it shoul
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Of course. But aggressive regen might be specifically more beneficial in the EPA test cycle or hypermiler e-peen measurement so that's what the electric car makers seeem to go for usually.
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No (is there even such a rating?) and I'm not saying Tesla is cheating, their strengths just seems to align with the EPA testing procedure for some reason.
As the EE video points out, the highway rating is probably the most important one. Few people will need 300+ miles of city range but on a roadtrip it's a real concern.
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their strengths just seems to align with the EPA testing procedure for some reason.
I would assume that the reason would be desire to maximize the expected value of range. You might think that highway range is a concern for road trips but whose car usage consists *solely* of road trips? If I were face with the same decision, I'd most likely make the same option since it makes the greatest sense to me.
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It's interesting that some manufacturers are now being more honest about range, rather than the usual cheating to get MPG numbers up they do on fossil cars. Removing everything not nailed down like the puncture repair kit, boot liner, car mats etc, using the lightest test driver they can find etc.
With Tesla there is also the added issue of them being able to alter the software at will remotely, meaning they can and do sometimes change the range of the car without permission from the owner and usually with n
Re:Bunk headline (Score:5, Interesting)
Tesla deserves some credit here but the article isn't very good.
They have big batteries and do a good job of keeping them at the most efficient temperature. They aren't the cheapest batteries but they are good.
They have decent drivetrains. Very nearly as good as the Hyundai one, which is the best in production so far.
The main reason they get good range is that their cars are very low and saloon shape. It's the most efficient choice, if not the most practical.
The big range numbers are a bit of a party trick through. The returns above about 250 miles and 75kW charge rate are rapidly diminishing. Try a tool like A Better Route Planner. Over a very long journey, say 15 hours, a Model 3 Long Range is only about 30 minutes faster than a Kona. You can find cases where it's a bigger difference but it's also a lot of money.
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My first attempt to test this showed almost 3 hours difference over a 17 hour drive: Model 3 LR RWD, Aero wheels: 17hrs 46 minutes. Kona: 20hrs, 37 minutes. Route: San Francisco to Yellowstone National Park.
If you want to try a more heavily traveled route: San Francisco to San Diego. Model 3: 8hrs, 35 minutes, Kona: 9hrs, 25
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You might be right, I can't remember the exact route I looked up. Here's London to Monaco:
https://abetterrouteplanner.co... [abetterrouteplanner.com]
https://abetterrouteplanner.co... [abetterrouteplanner.com]
https://abetterrouteplanner.co... [abetterrouteplanner.com]
So if you do it non-stop it could be to to 2 hours faster... For tens of thousands more purchase price. But in practice the stops in the Tesla are too short, you need more time to eat and pee. Most people stop overnight on that route, take in some sights and restaurants on the way.
Anyway, point stands, the returns are rap
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The situation may be different in Europe where Model 3s have CCS connectors instead of the Tesla connector.
But, yes, if you can take advantage of the time needed for body breaks, overnight stops with charging, the difference does become much less.
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They charge just as fast here but can also use any random CCS charger without an adapter. There are cars that charge faster like the Porsche but it doesn't make any real difference. Being 800V means less battery degradation though.
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Where do you get that from? At the individual cell level the voltages and currents are the same.
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P=IV so if you double V you halve I for the same power. Thus if you charge two cars at 250kW, one 400V and one 800V, the 800V one will be taking half the current per cell.
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no, I don't think that's true.
power to charge a cell is the same no matter what input volts or current (or even waveform) you give to the car.
the car converts it to 4.2v (roughly) for standard lipo style cells. for the specific chem tesla uses, there will be some other number. and a max C charge level, as well.
the notion of sending ac or dc to the car and at various voltages has nothing to do with cells and everything to do with dc/dc or ac/dc converters and BMS systems in the car.
the cells get treated th
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The car never converts it to 4.2V, the cells are stacked in series parallel so that each series is up to around 800V.
Since the amount of heat produced is basically determined by the conductor area and the current, halving the current with the same size conductor halves the heat. That's why high voltage DC lines are used for very long distance transmission - at 1000kV the losses to heat are lower and smaller conductors can be used.
So while the charge current per cell is the same a hell of a lot less heat is
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You can't just double the voltage of the cells. Lithium Ion cells (just like all battery cells) operate over a narrow range of voltages. The 800V is at the battery pack level. At the cell level, the currents and voltages are similar to those of 400V cells.
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Sorry I should have said per series of cells, they stack them into 400V or 800V series parallel configuration.
The Porsche peaks at 270kW (around 350A). For comparison the Model 3 can peak at 250kW (around 650A). The peak per-cell charge rate is lower in the Porsche but more sustained, i.e. it draws the peak current for much longer which results in an overall faster charge time.
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You don't seem to understand the relationship between power, voltage and current at the cell level.
For degradation (which is where this discussion started), all that counts is the currents and voltages of the individual cells, unrelated to how they are stacked.
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No, heat matters as well.
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I think that on a strict basis, that's wrong. Temperature matters.
Are you retracting your claim that 800V charging means half the current per cell? Hence charging at 800V doesn't improve lifetime of the battery pack?
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So it's like the VW diesel scam?
Try this one weird trick... (Score:4, Funny)
...for increasing your range, EV or ICE. Just raise the rear of your car. This way you are always going downhill.
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The gravity will also push more electrons into your motors.
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Is that how drag racers go so fast? By putting such large tires in the back and little ones up front?
Small wonder (Score:2)
Tesla has the 'Big Banana' batteries, the Australian PM said so.
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And by "banana" you mean "penis", right?
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All Tesla does is provide expensive mobil living rooms.
That's their target market. The cars don't really save money because there are far more frugal ways to put four wheels to pavement and your ass in the driver's seat. The entire ROI value proposition of a Tesla falls apart the moment you realize it doesn't have to be compared against the sunk cost fallacy of buying a similarly priced ICE vehicle.
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Lots of early studies get updated as battery life with thermal management is producing better results with increased longevity and lower degradation.
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Again, that assumes you were going to spend $38k+ on a new car in the first place. There’s dealerships in my neck of the woods that will sell you a Mitsubishi Mirage for about $14k, out the door. Is the Tesla really going to save you $24k over its lifespan?
Yeah, I’m not writing off that there is a market for folks who do have $38k+ to drop on a new EV and then don’t want to open their wallet much afterwards. But the idea that EVs represent the baseline level of frugality in the automoti
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All Tesla does is provide expensive mobil living rooms.
If that's what people want then I say let them have it.
While attending university I was a member of the solar car competition team. From that I learned the futility of electric cars. Electric cars will forever be hobbled by the problems of battery mass, the problems of getting electrical energy into the batteries, and the complexity of managing those batteries to keep them operational for as long as possible. This means that they will be heavy, expensive, and take a long time to charge.
What comes with th
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But then again, you could always post a link to your "facts" of weight reduction prior to testing.
Lucid Air has just had an independent EPA (but not official) test and gets 517 miles on their cycle so its possible that Tesla's crown of
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Sure. You could drive one of these around: https://images.app.goo.gl/YQTi... [app.goo.gl]. Pretty much infinite range!
Except most people want a car with lots of amenities, and when they're paying as much as a model S they want a decent amount of luxury. Actually, most Americans in the luxury market seem to want as much mass as possible. I assume that's why Porsche started making SUVs.
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EPA allows lies, ok thanks. (Score:2)
Surprised some company hasn't managed to bribe the EPA into a hyper-mile loop yet.
Bigger batteries give you more range, thanks captain obvious.
And wagon wheels with less rolling resistance would be even more efficient but less safe, we know that too.
Does Tesla have blended brakes yet? That's more regen gold right there. Even my hybrid has that (and yes in ECO mode my hybrid is mostly one pedal driving).
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Why? Tesla gives you maximum regen simply by lifting off the accelerator pedal. There is no more regen that can be achieved with blended brakes.
Also, as someone who has experienced total brake failure on a Leaf with blended brakes (fortunately, at very low speeds such that the parking brake was still effective), I believe that blended brakes are a bad idea.
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At what point of regen strength do the brake lights come on? It can't simply be only when pressing the brake pedal, if the effect is that strong.
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The brake lights do come on when you lift off the accelerator and let the regen work its magic. I don't know what the threshold is.
The image of the car in the screen shows when the lights come on, but the image of the brake lights is very small and doesn't show up well against the indicated red bodywork of my car.
Bigger batteries give more range? (Score:2)
You don't say. Of course, there is a threshold where diminishing results kick in, but except for that, I think a 5 years old with a model car could have figured this one out.
Does anyone remember the goal? (Score:1, Troll)
What is the end goal that electric vehicles are supposed to reach? Have we considered other means to reach that goal without the range limits and other problems of electric vehicles?
Here's my understanding of the goal, we want cleaner air, lower net CO2 emissions, and freedom from the economic and political issues of imported petroleum. Does that about sum it up?
It seems to me that with modern engines, improved fuel quality, and elimination of additives, the problems of lead, sulfur, nitrogen oxides, and
Infastructure. (Score:2)
I think you are looking at it from a cost perspective.
What you should be looking for is from a net loss perspective from energy conversions: Essentially even IF we where to use hydrocarbons to make electricity, there is a benefit of size to running a mega power plant, with far better filters than you can have for each and every single generator or engine producing some electricity for industrial usage.
Power line losses are neglishable compared to net loss in a ICE engine running a automobile. But that does
Re:Does anyone remember the goal? (Score:5, Interesting)
Ugh. Every time Tesla comes up you mention the idea of hydrocarbon synthesis. Like a broken record. You get told why it is a stupid idea, but you keep posting it.
It's technically possible, but extremely inefficient. I don't want to google the numbers, but driving a mile on synthesized hydrocarbons consumes about 25 times as much energy as just driving an electric car (due to inefficiences primarily in creating the hydrocarbons but also in internal combustion engines).
Ultimately, this technology would only be useful if we had free energy. It isn't really a carbon neutral process if it takes massive energy generation. Perhaps once our grid is extremely green it would make sense to generate some fuel with surplus electricity, but even then it would only be in very limited quantity - because hopefully the surplus energy will be charging batteries or moving water up dams or so forth.
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Please stop enabling these ppl. Anyone who argues that ICE vehicles are more better than electric vehicles is dumb or never made it out of middle school science. Burning anything to make a wheel turn is ridiculous at our current level of technology. Currently its all about money and tribalism. Tribalism of ppl not making a cent of of the continued use of ICE vehicles.
blindseer is our special nuclear boy. He has it stuck in his head that using nuclear reactors to synthesize hydrocarbon fuels will make adoption of nuclear reactors more appealing, probably because of the aforementioned tribalism. The fact that it's thermodynamically colossally stupid does not enter into his 'reasoning' at all.
This post demonstrates even more of his ignorance than usual. He seems completely oblivious to the fact that hydrocarbon combustion in air is always stochastic, with all sorts of c
Hight conversation losses with synthetic fuels (Score:3)
The energy efficiency of creating synfuels from electricity, and then powering an internal combustion engine is abysmal. An ICE converts only 30% of fuel energy to torque, and on top of that creating the fuels takes a large amount of energy in itself. According to this report from the European federation Transport and Environment, the energy efficiency of synthetic liquid fuels + ICE is only 13% - the rest is lost. A BEV can reach around 75%. The only vehicles beating that are direct-powered from caternary
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Well good luck (Score:2)
Wheels in motion (Score:2)
And the magazine shares this tip for prospective Tesla customers. "Based on the road-load data it has submitted to the EPA, opting for 21-inch wheels on a Model S Long Range Plus will cut the range by nearly 80 miles.
Yes. That must be it. The size of the wheels. It's increasing weight, and causing more wind drag due to a phenomenon called "plumbum pes".
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Rolling resistance increase leading to a 20% reduction in range? That's a bit of a drag.