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  • tipoo - Monday, February 18, 2013 - link

    They really are the single bottleneck on an incredibly wide spectrum of things, aren't they? From cell phones to being able to wean ourselves off gasoline. Reply
  • JlHADJOE - Monday, February 18, 2013 - link

    Unfortunately they're the best we currently have.

    Lithium Ion is certainly miles better than when we were using NiCD or NiMH.
  • JPForums - Tuesday, February 19, 2013 - link

    Well, there are other options. Silver Zinc (AgZn) batteries are safer than Lithium ION / Polymer as they contain no hazardous materials and don't suffer from thermal runaway. Note: Older Silver Oxide cells contain small amounts of mercury.
    With lithium based batteries, you have to trade off specific energy (Wh/Kg), energy density (Wh/L), and maximum discharge rate. While advanced Lithium technologies might allow them to achieve higher specific energy or energy density than AgZn, they often come at the expense of each other. For instance, Li-Polymer has higher specific energy than Li-ION, but it also has lower energy density and discharge rate. You would have to use more packs in parallel to achieve the discharge rates of Li-ION or AgZn. They also have a more limited life, even when they aren't in use.
    AgZn also has to make tradeoffs, but as less work has been put into them vs lithium, the characteristics don't vary nearly as much. Looking at the overall characteristics of any single AgZn cell paints a much more impressive picture when compared to a single Lithium based cell.

    Of course, there are still barriers to entry. AgZn has lower cycle durability. Seeing as Li-ION managed to increase their cycle durability from several hundred cycles to over 1200 cycles, I'd expect AgZn could overcome this with a little work. The largest barrier to entry is most certainly cost. Don't know if there is much we can do about it either. Still, if research can improve AgZn by the amounts that it has improved Lithium based cells, they may become worth the cost.
  • JPForums - Tuesday, February 19, 2013 - link

    Also note Silver Zinc > Silver Oxide. Reply
  • Gokimoki - Tuesday, February 19, 2013 - link

    Or forget batteries entirely and go for ultra capacitors. We really need to start pumping in the same kind of r&d funding that li-ion gets into UC's. That would pretty much solve issues with EVs. You'll never get the same energy density as batteries, but being able to recharge in seconds to minutes, weigh MUCH less (partially negating the lower energy density), no toxic components, and virtually unlimited (100 000+) charge-discharge cycles more than make up for it. Reply
  • Daniel Egger - Thursday, February 21, 2013 - link

    > You'll never get the same energy density as batteries, but being able to recharge in seconds to minutes

    You forgot to mention the fact that there's close to zero infrastructure available where you can actually consume that kind of necessary energy to charge in "seconds to minutes". If it was you'd still have the problem that no power grid operator is going to allow these duty cycles. Plus the cables would be massive and the safety mechanisms ridiculously hard to implement. If they'd finally manage to get the range up to the needed levels that would be even harder to do. Will we see single digit minute charges? Possibly. Seconds? Never ever.

    That's exactly the reason why I think battery driven EVs are never going to go mainstream.
  • greevar - Friday, February 22, 2013 - link

    You're right. The grid, as it exists, will not support UC powered cars, but that's not a valid reason to dismiss the idea. The power grid is already an outdated design in need of a change; it might be worth making changes that support new power grid topographies and consumption. Reply
  • Rasterman - Sunday, February 24, 2013 - link

    Totally false, "stations" could simply have their own ultracaps that are charged overnight or a long period, or some other method of storing a lot of energy, molten salt, giant flywheels, etc.

    Getting the energy to the car is only an engineering problem. Drive over an automated plug, station detects you are there and automatically debits your card and moves a coupler 4" to mate with the bottom of your car, which feeds directly into your battery, and offloads kJ of energy in seconds. The interface can be whatever is needed, a 5" connector is needed? No problem, its 100% automated and 100% safe.

    After electric cars are mainstream trickle chargers can be installed in or on the sides of roads, no physical contact is required, but would probably be more efficient. Thus you would NEVER have to stop and recharge.

    The possibilities are endless, anything can be done.
  • greevar - Monday, February 25, 2013 - link

    Like I said, "as it exists". Reply
  • ikkai - Wednesday, February 27, 2013 - link

    Hello, I totally agree with you. A recent breakthrough on super capacitors is exactly what is on your mind and it will definitely change our everyday lives. Here is a video explaining the technology
    For those who prefer to just read :), a new carbon based energy storage capacity dubbed as "super supercapacitors" can obtain the same energy density as li-ion batteries while having 100,000+ refill cycles, under a minute charge durations and everything else capacitors are good at.
    This thing is like a miracle, they produce it by using normal DVD burners! You can even dispose it by using it as fertilizer for plants! If you got hyped up, continue to read at here (extremetech article):

    p.s. By the way, thanks to the author of the article :)
  • Wolfpup - Thursday, February 21, 2013 - link

    Are they? Lithium ages even if it's not being used. I'd feel more comfortable with a NiMH battery pack in a vehicle like the Prius than with Lithium.

    What happened to super capacitors?
  • Exodite - Monday, February 18, 2013 - link

    25-100% increased power usage at a mere -11C?

    I guess there's a reason no one here (northern Sweden) particularly fancies EVs. I shudder to think what the fuel economy would be like at -40C.
  • Kjella - Monday, February 18, 2013 - link

    No, 20F = -6.7C so it's worse than that. Also I would assume this is the battery charge when they're new. I'd sure like to see tests on a 5-10 year old battery to see how reduced capacity and high drain go together. I suspect it would not be pretty.

    Here in Norway you get massive advantages from buying an EV (no one-time fee, no yearly fee, free toll roads, ride the bus lane, publicly sponsored charging stations) which is the only reason they've managed to sell a few thousand.
  • Exodite - Tuesday, February 19, 2013 - link

    Yeah, I calculated from 20 rather than from 12. My bad. :(

    I could see EVs being used for something like inner-city taxi services in the southern end of the country but generally speaking both Norway, Sweden and Finland suffer from the same concerns here... cold climate and long distances.

    I'd rather see a quicker push into fully synthetic diesel solutions for us.
  • elmicker - Monday, February 18, 2013 - link

    "the previous Top Gear vs. Tesla, which was an outright sham"

    Well, that's a libel.
  • jonup - Monday, February 18, 2013 - link

    So was the lawsuit.
    What is so special about Model S? It's fugly and it feels like made in a shed. (I've been in one and it felt cheap.) Doesn't even stand a chance next to Fisker Karma. And just like the electric Elise before, it took on honest review to destroy the PR/artificially created fame.
  • Azethoth - Monday, February 18, 2013 - link

    1) The model S is a sedan. You compare it with a Lexus or Mercedes sedan.
    2) The Fisker Karma is a sports car. You compare it with a Porsche or the Tesla Roadster.
    3) The review was in no way honest. Major egg on his face and NYT face.

    Your post is bizarre. Do better in the future.
  • jonup - Tuesday, February 19, 2013 - link

    Fail on this one alone:
    /quote 2) The Fisker Karma is a sports car. You compare it with a Porsche or the Tesla Roadster. /quote

    Both Model S and Karma are 4-door sport sedans. Except one is fugly and the other is gorgeous. Tesla Roadster is what the name says.

    I really don't get your first point. Are you arguing build quality?! I've been in one and it was as refined as... refined and Tesla Model S do not belong in the same sentence.

    They tore apart the guy that gave objective review of the POS Chrysler 200. It beats me how car companies have better PR than newspaper.

    You know what, forget what I wrote. Go get yourself a Model S with a big touch screen "tastefully" slapped in the middle. It seems to impress most people.
  • Activate: AMD - Tuesday, February 19, 2013 - link

    "Except one is fugly and the other is gorgeous."

    Thats your opinion, don't pass it off as fact. I personally think the Fisker looks like the sick offspring of a Maserati and the Cheshire Cat from Alice in Wonderland.
  • Spunjji - Tuesday, February 19, 2013 - link

    Don't let your logic get in the way of a fan-boy rant ;) Reply
  • jonup - Tuesday, February 19, 2013 - link

    Fan-boy? How did you come up with that? I have had a limited interaction with both vehicles (which I would assume is more than both of you have had combined). I do not own either one and I do seek to acquire neither. My opinion about looks and refinement are result of my personal experience and not from reading the targeted manufacturers response to the NYT test.
    And as far as looks go, Compare the front end of 10+ year old Maserati 3200GT and Model S and try to find the differences. Photohunt at its best!
  • Spunjji - Tuesday, February 19, 2013 - link

    It's not about Pr. It's about how the reporter made claims that were not factually substantiated and then failed to explain the discrepancies. Note that I am not including bits like the "he drove around in circles" claim by Tesla which he more than adequately explained. I'm talking about why he didn't charge his damn car properly. Reply
  • steven75 - Tuesday, February 19, 2013 - link

    You know what they say...Beauty is in the eye of the beholder.

    I just saw the Fisker at the Chicago Auto Show on Sunday and thought it was one of the ugliest cars there.
  • Heathmoor - Monday, June 10, 2013 - link

    The Fisker Karma and the Tesla Model S aren't of the same category. The Karma has only 4 seats and a small boot whereas the Model S has 5(+2) roomy seats and a very large trunk. The only clear advantage of the Karma is that can recharge its batteries with an IC engine while moving. Reply
  • Aikouka - Monday, February 18, 2013 - link

    A sham on whose side? Reply
  • shokunin - Monday, February 18, 2013 - link

    Sham by Top Gear, they had scripted all the events before they got the car. Jeremy running out of juice, pushing the car into the garage because it was dead, were all scripted.

    The result of the lawsuit was Top Gear isn't a car review show, it's entertainment and not journalism.
  • jonup - Monday, February 18, 2013 - link

  • ricardoduarte - Monday, February 18, 2013 - link

    I think Elon Musk is a bit of tantrum queen, he likes to blow things out of proportions a bit, Even with the whole thing scripted, top gear had a point and the whole would actually happen, and thats a reality of the electrical cars, specially when throwing them around a track, what interests me is if the financial advantages and if the car performance can be as exciting as a petrol ones, are good enough to live with range anxiety (at the beginning at least). Reply
  • Azethoth - Monday, February 18, 2013 - link

    No, perceptions matter. If I had an electric car company I would take my lumps on extreme weather performance and charging times. These are the facts of life for current battery tech.

    However, I would not sit still for hatchet jobs. Neither by Top Gear nor the NYT.

    Failing to charge your EV is not a limitation of the EV. Its a limitation of common sense. The NYT failed at that.

    As for top gear, ok, if I run a vehicle out of gas / charge then it will need a tow. Omg! Wow this is ground breaking entertainment. I like Top Gear but feel uncomfortable about what they did.
  • jonup - Tuesday, February 19, 2013 - link

    This is sensible piece of advice.
    If you do not have common sense do not buy Model S, you will fail to charge it. On the other hand, if you have common sense, don't waste you money and get a better car.

    ... and on that bombshell...
  • wetwareinterface - Tuesday, February 19, 2013 - link

    top gear did a hatchet job???

    they said the car performed well with great accelleration and a fast top speed. handling wasn't as good as the lotus the car is based off of. range when driving fast was also dreadful.

    overall they said the car was pointless given that it cost more than the lotus, had only marginally better accelleration and top end, and would stop after 55 miles of hard driving and require 8-12 hours of recharging.

    the fact is the tesla roadster is a bad idea all around and is only for the ultra rich to collect and use as a toy on short runs.

    the tesla s also has abysmal range in cold weather, and takes a along time to charge. it's completely unusable for an only car based on range alone. you might as well state that the tesla's 311 miles is the max driving per day given the recharge time.

    when they make hydrogen cars a reality and store electricity as said hydrogen instead of in a battery then a car that runs off the grid will make sense. until then unless there's a huge leap forward in battery technology we won't see a practical electric vehicle.
  • Aikouka - Wednesday, February 20, 2013 - link

    That link is the exact reason why I asked.

    I remember when the Top Gear lawsuit first became news, and I gave Tesla a fair shot with it. Since the segment happened a bit prior to the news, I had to rewatch it to properly form my opinion. Honestly, I couldn't see what Musk was belly aching over. Probably the first 75% of the review was praising the upsides versus a petroleum-based vehicle, and the latter portion was discussing the downsides (range and charge time).

    After this latest issue, it's pretty obvious that Musk needs a few lessons in being a company figurehead.
  • Beaver M. - Tuesday, February 19, 2013 - link

    But its true!
    Ive driven one myself and it is 100% true that the batteries dont last very long if driven like a sportscar! It also had quite a few other quality issues.
  • Death666Angel - Tuesday, February 19, 2013 - link

    Duh. The suite was dropped by the judge btw. The show was scripted and edited in a way to provide entertainment but nothing they states was untrue. Reply
  • JPWhite - Tuesday, February 19, 2013 - link

    It's only libel if it's not true. Reply
  • othercents - Monday, February 18, 2013 - link

    I think we should be looking at changing car testing now since obviously there has been significant discrepancy in multiple vehicle MPG tests and I don't think they correctly reflect real world driving compared to older vehicles. In the past you could count on a 2-4MPG difference between tested MPG rating and real world, however now I have see as much as 20MPG difference which if properly informed a buyer might choose a different vehicle with lower tested MPG, but gets better real world MPG. Reply
  • blowfish - Monday, February 18, 2013 - link

    Good article, Vivek, and the more so coming from an actual EV user.

    The fact remains that people are obsessed about range - whereas most commutes are only a few miles, and so even the 46 mile range of the Leaf in worst case conditions is more than adequate. For longer trips, maybe a charging trailer equipped with a generator would be the way forward until such time as battery technology has improved.

    Sadly, most drivers are probably unable to adapt their driving styles. Every day, I see folks flooring it between stoplights, rather than driving at the appropriate speed so as to get the "green wave". Those who do try to drive sensibly find others cutting in front of them, desperate to gain those one or two places that are evidently such an important part of their lives....

    The real way forward for shorter commutes, however, is for people to get on their bikes, and get healthy as a side benefit. Here in Louisiana, however, cyclists are often assumed to be people who can't afford cars, and regarded as a nuisance by most drivers, and when you ride a bike on the road, you are aware that you are risking your life.
  • Guspaz - Monday, February 18, 2013 - link

    Models of the Nissan Leaf sold in cold-weather countries like Canada feature various changes to function better in low temperatures. One example is that the Canadian model comes with a battery heater to improve efficiency at low temperatures, while the US model, to my knowledge, does not.

    It's not really fair to test the US model of the Nissan Leaf in cold temperatures. One of the cold-weather models should have been tested instead.
  • bobbozzo - Monday, February 18, 2013 - link

    20F is not very cold.

    It was 27F in southern California recently, in the LA metro area.
    In the mountains would be even colder.

    Also, it gets below 0F MANY places in the US.
  • cmart - Tuesday, February 19, 2013 - link

    Gets? It stayed below zero, day and night, for eight days here recently (Northern Minnesota). Reply
  • relztes - Monday, February 18, 2013 - link

    How can it possibly be unfair to test the US model in the US? If they took it to Nunavut for a test at -30 F, I'd see your point, but there is nothing extreme about 20 F in at least half of the US. Reply
  • Kerdal - Monday, February 18, 2013 - link

    Trust me, they don't have to go as far as Nunavut to test at -30F (-35°C), it was -45°C (-50F) a few days ago over here (QC) haha

    Most cars wouldn't start, I wonder what kind of range an EV would get at those temperatures but that's probably why we don't have any over here.
  • Alexvrb - Monday, February 18, 2013 - link

    Bingo. The Nissan Leaf is a POS. It sucks horribly in cold weather (anything below freezing point of water, apparentely). It also uses air cooling for the battery pack, so it suffers quite horribly in hot climates, especially long-term. The Leaf is an all-compromise car. The Model S is leaps and bounds better, though it's got a price tag to show it.

    The Volt and even more common hybrid designs are a better option at this point, if you don't have the cash for a Tesla Model S.
  • Alexvrb - Monday, February 18, 2013 - link

    Err, and by better option I mean if you are only considering EVs, PHEVs, etc. There are lots of good options depending on how you're driving and what your needs are. For example small diesels or specially tuned small turbo gas motors for highway commutes. Reply
  • IKeelU - Monday, February 18, 2013 - link

    Thanks for this article. It's nice to hear an educated response to the controversy. Reply
  • ricardoduarte - Monday, February 18, 2013 - link

    Without having much to do with post, i have a few questions since the Vivek is electric car driver.
    I admit that i know little about EV's and I am a petrolhead, which loves everything about petrol cars, however i always wondered what would be like to compare the fuel expense with a petrol car (I am in uk and both are quite expensive at the moment).

    I wonder if you have any other cars (for longer journeys), or this is the household main car?
    - How many times do you charge your car per day?
    - Have u noticed any big advantage financially to the use of an electric car?
    - Do you avoid random driving because of fear of running out of charge, or that you might actually need the car later?

    Sorry for the questions, but i always wondered if drivers of electrical car feel restricted because of the battery recharge time, and if the financial advantages are big enough to compensate any anxiety that the presence of batteries might give.
  • happycamperjack - Monday, February 18, 2013 - link

    The fundamental problem of pure EV car is simple, Limited Freedom. Since the introduction of car, it has been the symbol of freedom throughout ages. How many hollywood films have you watched that have cars driving into the sunset? Sure current EV might last you 200 miles or 300 miles and that's plenty for everyone, but that anxiety of running out of juice is always gonna be in the back of your mind. People don't want to wait to charge their car, that directly limited their freedom of movement. If they don't mind that, they probably wouldn't mind public transportation either. So what you end up is a product that's perfect for engineers who can plan ahead and optimize their schedule around it. For anyone else it's a product that's unproven, anxiety inducer, pricey, and just a chore to deal with.

    Plug in hybrids make a lot more sense. For city driving, the 30+ miles range is enough for most of the people during work days. For vacation or weekend getaways, that's where gasoline comes in. Knowing that you would not have to plan all the "charging" stops well ahead of time, makes life so much easier. Volt is a good start, but it's pretty ugly and feels cheap inside out when you compared to cars in the same price range, that's why it's not selling well. Fisker's reliability problems from multi sourcing parts(reminds me of F35) is scaring away potential buyers. The market is really waiting for a winning design. I really hope Tesla would consider adding at least a small gasoline motor to keep the electric motor running at perhaps 50% capacity when it's out of juice.
  • IKeelU - Monday, February 18, 2013 - link

    The points you make about EVs could become less relevant over time. Namely:
    - Recharging stations will become more common, making the more limited range of an EV less of an issue, and eventually (hopefully) a non-issue. After all, limited gas stations didn't hamper the adoption of gas-fueled cars a century ago.
    - Recharging times will shorten as battery tech improves.
    - Battery charges will increase as battery tech improves.

    I agree about the hybrids. I rented a For C-Max for a week and mostly did city driving (except for the 30-mile drive to and from the airport), and the top-off before returning to the airport cost me about 8 bucks. I'm pretty much sold on renting hybrids from now on.
  • happycamperjack - Monday, February 18, 2013 - link

    Thanks for the comment. As for now, there are more than 10x the gas stations than charging stations in US, and a lot of them are in california. Not to mention it takes 10 times longer (in charging stations, even longer without it) to charge a EV than a gasoline car. And if everyone's doing it, it's gonna overload the grid and force more "dirty" electricity production to keep it up. I think all this add up to an inconvenient solution for most of the population in US. Like I said, for more well organized people like engineers, this would not be as much of a problem. But why have a problem when you can have none? Our electric technology and the grid is not quite there yet.

    This situation reminds me a lot of Tablet PC. The concept was good, but technology(capacitive screen and battery) wasn't there to make it good enough to sell to the mass.
  • melgross - Monday, February 18, 2013 - link

    Try 1,000 to 1, or more. But the point is that so far, these EVs, are very range limited, and people expect a $100,000 car to do better. So while these road tests aren't exactly fair, or done well, they do illustrate the point that they come nowhere near a gas fueled vehicle Reply
  • Kjella - Monday, February 18, 2013 - link

    "After all, limited gas stations didn't hamper the adoption of gas-fueled cars a century ago."

    That's a rather unfair comparison since it's trivial to bring extra gas with you in a can or a barrel, while there's no easy or cheap way to extend your battery range.
  • guidryp - Monday, February 18, 2013 - link

    "Plug in hybrids make a lot more sense. "

    Not to me it doesn't, though I understand the initial appeal of the argument.

    If I am going for a plug-in I am getting rid of the ICE components. With a PHEV, you are essentially always carrying dead weight. You are running in gas mode, pulling around a huge heavy battery of little use, or you are running in EV mode, pulling around huge heavy ICE components you aren't using, and you have the expense of the battery and the maintenance of an ICE car.

    Most households are multi-car anyway. Have one pure ICE car, and one pure EV. Each of those is simpler and better suited to it's main role.

    Even without a second car, the only time I drive more than 100 miles is on vacation. I could simply rent a car for that (and have many times even though I own an ICE car).
  • happycamperjack - Monday, February 18, 2013 - link

    Thanks for the comment. I definitely think there's a market for pure EV, but for majority of the population, I just don't think they want deal with the chores that come with it especially when it's costing more and unproven in reliability. At least with plug ins, you have less things to worry about, but even that is too much to handle for a lot of the people.

    As for the dead weight argument, I agree,.I really think there should be more research on combining these two things together to save weight and space. Toyota did a good job with prius. I think they are the prime candidate for designing a new generation of plug ins engines that can be accepted by public.
  • phoenix_rizzen - Monday, February 18, 2013 - link

    Or, go for the best of both worlds: a tiny, RPM-optimised diesel generator that does nothing but charge the batteries. Doesn't touch the drivetrain in any way. The Volt went about halfway down this path, but went with a gasoline engine that touches the drivetrain in certain circumstances.

    Diesels can be better optimised to always run "in the sweet spot" to get the most bang-for-the-buck. And, if its only used to charge the batteries, you only have to worry about a single drivetrain. Treat it like a pure-EV vehicle, since (in essence) that's what it is. You're just carrying around a very small generator for those longer trips.

    Making it a plugin would just be icing.
  • beginner99 - Tuesday, February 19, 2013 - link

    Well said. EVs just require to many compromises. Adjust driving style? Seriously? Then the charging. If you own a house and can just easily install such a station ok but at least were I live most people rent and a fix parking spot is often not included. And even if it is you will still need the go-ahead from the owner before you can install anything which by itself is not easy (the power must obviously be taken in such a way that it adds to your "power usage meter").
    If you can't charge at home it's a no go.

    The only real solution are fuel cells. You have a smaller battery than these current EVs which is constantly charged by a fuel cell. Hence you don't have the downside of the fuel cell (eg. no peak output) and gain range. The small battery should be standardized (haha, i know not going to happen) for easy change.

    Another alternative would be an additional, standardized, switchable battery. Instead of fueling or charging you just switch the battery at the "gas station". But I guess with current tech batteries in a size that make this work would just not have big enough mileage. But still adding 20 miles might make the difference. And larger cars (= more space) could have more of them.

    But yeah, current tech has evolved over 100 years, it is so much better, its impossible to come up with something new that is just as good and convenient.
  • guidryp - Monday, February 18, 2013 - link

    Once you learn the car better, you can get more out of it even in the cold

    One Canadian Tested his Leaf at -13c after a 4 hour cold soak:

    By backing off on cabin heating, and using the heated seats/steering wheel, you can save power.

    He went 125 kms (~78miles). Mind you this is mostly city driving. Highway eats power more, but it is also shorter in duration, so less energy is spent on heating the driver/mile.

    Definitely you don't buy an EV if your round trip commute is on the edge of your range, you want a healthy cushion and bigger cushion if you live where it gets very cold. And you certainly don't forgo a complete charge before an overnight trip in an EV.
  • Midwayman - Monday, February 18, 2013 - link

    I'd be interested to see data on the -20 test without the heater running. How much of that load is just electric heat, and how much is the battery capacity being diminished by cold? For example if you made an electric car with a propane heater what sort of range increase could you expect? Reply
  • bobbozzo - Monday, February 18, 2013 - link

    It was 20F, not -20F.

    The hyphen/dash on the first page is confusing and should be changed to a colon.
  • AVonGauss - Monday, February 18, 2013 - link

    While I agree that non-traditional automotive review methods need to be reconsidered, I think there is one take away from New York times article and that is the estimated range accuracy. We've all probably experienced it in laptops, where you have 1:41 minutes remaining that an hour later suddenly becomes 5 mins remaining. While using a device like a laptop or tablet that may be acceptable, the importance of the estimate accuracy is higher when using a motor vehicle. This is one case where you definitely want to be extremely conservative, even it makes your product seem a little less appealing at first glance. Reply
  • sweenish - Tuesday, February 19, 2013 - link

    As far as I understood it, the car was fairly accurate in telling the NYT guy when it would die (the car told him it wouldn't make it close to the next charging station). He just decided to act surprised when it did die. Reply
  • shokunin - Monday, February 18, 2013 - link

    There's several factors that affect range in an EV, the heater/HVAC as described in the article.

    Active heating and cooling of the battery pack. The ability to maintain temperature of the pack is paramount to keeping the battery operating within thermal limits, whether from weather or excessive current draw (driving fast) creating heat.

    Driving style and speed. The faster you drive, the increased wind resistance uses more energy the faster you drive. This is also due to the fact that many EV's simply have one gear, there is no "overdrive" gear on an EV.

    For the Model S, it takes more energy getting the car "up to speed" say 40-50 than it is staying at that speed. Ironically, in the city driving with lots of stop lights, it will use more energy than coasting along the freeway.

    The NYT writer did a poor job explaining these and explaining the fact that one has to change habbits when it comes to an EV. Fully charge the car overnight, and when you are at a Supercharger, charge to full. You don't fill up your car to make it to the next gas station, you just fill it up to full. When you take a road trip on an ICE, you fill up whenever you've got a 1/4 tank left. He sort of missed the common sense part of charging.
  • mchart - Monday, February 18, 2013 - link

    I had thought the high-end sports car like EV's had at least a two gear transmission.

    I know for a fact that there are plenty of high-'output' racing EV's that are linked to a two speed transmission. A 'driving applicance' (Car that people who just need A-B transportation buy) doesn't need gearing though. Even more so in the US given the fastest most people ever go is 60-70mph.

    Funnily enough; I'd only ever buy an EV right now for performance reasons. Not for going 'fuel-less' reasons. The essentially straight as an arrow torque curve of an electric motor is amazing for racing application.
  • DParadoxx - Monday, February 18, 2013 - link

    While I appreciate seeing this sort of article on AT you needn't insult Musk's article. He identified inaccuracies in the NYT article and provided clear and easy to read graphs to back up his argument. Several of your graphs by comparison are crowded and difficult to read, even for an engineer. Reply
  • relztes - Monday, February 18, 2013 - link

    Well, Musk's article really was exaggerated. Broder spent less than 2 miles out of 500 over 75 mph, but Musk made a big deal out of it. Same for the half mile around the parking lot, which would have to be the world's weakest attempt at draining a battery. He points out the 40 miles for which the heater was set at 72-74 F after Broder noted the declining range, but ignored the last 60 miles of that leg where the heater was set at 64-66 F.

    Now Broder did seem to exaggerate about how slow he was driving, and some of his decisions were pretty stupid. The decision to unplug at 35 miles was by far the dumbest. I'm really curious about Broder's claims that Tesla gave him bad advice, because he mentioned some really stupid things. Tesla might want to reevaluate the employees answering the phones. Even so, you'd have to be an idiot to trust some of that stuff. Who could possibly believe that frequent acceleration and braking will extend the range of your car?

    Anyway, I completely agree with Vivek's assessment of Musk's article as vitriolic. His legitimate points were drowned out by his cries of "OMG HE DROVE 80+ MPH!!" when only a small portion of the drive was even over 70 MPH.
  • jonvaustin - Monday, February 18, 2013 - link

    The fundamental problem is basically the whole article. If a EV is to be successful the range has to be there for the right price, a good number of miles off a charge, and about the same experience as we currently have.

    We have what 100 years of cars under our belt now and for the longest time operation has been a similar experience that is taught in a persons teens and carried throughout his or her life time. For a EV to be mainstream for that consumer to have to take into account temperatures, this or that is foolish. Why it will never take off.

    A good example is Apple with the iPhone 4. It got crappy reception from improper antenna placement and the solution was to tell people to hold it the right way? That is fail. Case in point future models fixed the issue. To tell a consumer that you have to hold the phone a certain way and not the way you naturally hold it was not to popular. The same is with EV cars.

    Another case is why we all use the slow inefficient QWERTY keyboard. Why? I learned it as a kid because my parents learned it that way. There are a dozen better solutions and ZERO catch on primarly because of that reason.

    To ask me to learn about battery dynamics and to drive differently then I currently do in my gas based car will never work for the general population to be successful. What needs to happen is a radical breakthrough in energy storage tech so it becomes a mute issue.
  • Luke212 - Monday, February 18, 2013 - link

    New York Times article link is broken in first paragraph Reply
  • Galcobar - Monday, February 18, 2013 - link

    One area neither side in this dispute has addressed -- that I've read -- is whether extremely cold temperatures affect the accuracy of the car's internal sensors.

    Particularly, the level of charge remaining in the battery.

    Elon Musk's defence is based largely on the level of charge remaining in the battery according to the log at various points, while reporter John Broder says his behaviour was guided by what the car was telling him (and what he then relayed to Tesla customer service).

    As an aside, The Times' public editor -- a position meant to provide self-criticism to the paper and effectively act as an ombusdman -- wrote an interesting piece on the controversy:
  • relztes - Monday, February 18, 2013 - link

    Roughly estimating the power consumed by the heating system in the Leaf, I get 3.4 kW (on the UDDS HS drive cycle at 20 F). It's going to be a pretty big limitation if EV manufacturers can't figure out how to reduce this. They need to consider adding insulation, using heat pumps, and recirculating as much cabin air as possible. Obviously there isn't much room for insulation, heat pumps have limited temperature ranges, and some outside air might be necessary for proper ventilation, but they need to do something or they aren't going to have a very popular product in cold weather regions.

    On second thought, it looks like Tesla isn't doing too bad. The range was only degraded by about 20%, so if they just factored temperature and climate control settings into their range calculations, people might not be too disappointed. A 200 mile range only looks bad if the car claims it'll go 240 miles.
  • chipkin - Tuesday, February 19, 2013 - link

    The 2013 Leaf SV and SL models switched to a hybrid heat pump / resistive heating system. I am the EV sales specialist for a large Nissan store in the Chicago area (where we routinely see -10 F winters and 100 F summers). I keep in close touch with my customers, and the cars have performed well within their expectations. The lease price for a Leaf is low enough that if you have a 50 mile or less daily round trip (like 80% of all US drivers), the car is effectively free once you figure in the savings in gas and maintenance expenses (no oil changes, filters, belts, etc...). Reply
  • vangman - Monday, February 18, 2013 - link

    Vivek, could you explain why you consider the Top Gear episode was a sham? Reply
  • Hulk - Monday, February 18, 2013 - link

    While I'm a mechanical engineer it doesn't take much thought to understand that Tesla has a history of making claims that physics doesn't allow.

    Case in point. The Model S is lucky to get 3miles/kWHr. So if you drained the battery fully that would be 85x3=255 miles. Best case. But the reality is you'll kill the battery quite quickly discharging that deeply. A more realistic discharge is what GM claims with the Volt. It uses a 16kWHr battery and discharges to about 11kWHr. Or about a 70% discharge if you want the battery to last more than a few months.

    255x.7=178.5 miles. That is the real long-term viable range of the S.

    I have argued this with a Tesla engineer and all he can tell me is that they have "super secret special battery technology" or some other BS.

    There is nothing wrong with this range either. But Tesla should be up front about the numbers.
  • Scootiep7 - Monday, February 18, 2013 - link

    You hit the nail on the head in this article. I live in Iowa and own a Hybrid Escape. In the spring and fall it's great. 31-33ish MPG (wife has a bit of a lead foot, up to 35 when I drive it =D). And in the summer it's not bad, generally 28 - 32. But as soon as we hit late fall and throughout winter, FORGET ABOUT IT! We're averaging 23 mpg. And it's no better (in fact worse) in two of my friends Prius's. Electric cars simply aren't practical for cold weather and Hybrid vehicles currently don't live up to the hype in these conditions either. It regularly dips down into the 20 to -10 range here and occasionally hits -25 (most recent record was -36 four years ago). My point being, if you want to sing the praises about these cars and the wonders they do for "mother earth" and can save you enough to buy a small house, by all means, go for it. But don't outright lie about them to get people to buy them. At the same time, my 1997 Olds Cutlass Supreme still gets the same 20mpg city, 25 hwy it's been getting since I got it 11 years ago with 124k miles on it then and 176k miles on it now. It puts out heat and AC, drives the same range and takes less than 2 minutes to go from empty to a full tank no matter what the weather. That kind of convenience and practicality is something we simply can not offer in an electric vehicle at this point in time. Should we keep developing them? ABSOLUTELY! But should we start lying about them to get people to buy them? Good God no.

    And the sad thing is that it's the same with ALL eco friendly products. Take CFL bulbs for instance. Supposed to save on average 4 times the electricity over a conventional blub and last around 10 times as long. And in an ALWAYS ON situation they work GREAT! But in a regular residential dwelling? AGAIN, FORGET ABOUT IT! I have 4 large ziploc bags in my basement full of CFL's with dead ballasts because the lights are frequently turned on for only brief periods during the evening and morning and then switched back off whenever we leave a room or the house to go to work. In my experience, they have actually died FASTER than regular incandecents. AND FOR FIVE TIMES THE COST!

    The testing methods on ALL of these kinds of products needs to undergo some very, very harsh scrutiny and change radically. I couldn't agree with you more Gowri.

    ...Oh damn it, locked my "rant" key up again. I apologize.
  • gauss jordan - Wednesday, February 20, 2013 - link

    Conventional cars don't work all that well either in cold weather, but people is more used to those problems. And usually amply supplied with blissful ignorance.

    The oil does not flow as it should before it is warm enough. A cold engine cause humidity to form on the cylinder walls which end up in the sump, where it changes into acid. The probability that the engine don't start at all increases a lot. And so on ...

    For short trips EV's have some user benefits, like instant heating of the windscreen, instantly ready to drive after it is "started" ... , but as most technologies, with the benefits you also get the "costs"

    CFLs should be banned. It really irks me when I see them promoted as eco friendly. Each CFL bulb contain more than 3 mg mercury!
    Because the CFLs does not irradiate infrared light, the air temperature must be higher for the same level of comfort, and therefore CFLs often contribute to significant _higher_ total energy consumption (in the parts of the world where heating is necessary.

    It should be mentioned that the same corporations that lobby for CFL bulbs, reduced the longevity of light bulbs from 2500h to 1000, on purpose. Now a 2500h bulb is regarded as "long life".
  • mtwardochleb - Monday, February 18, 2013 - link

    Any comparison of range between the Leaf and Model S in cold weather is meaningless if you don't discuss the differences in their thermal management.

    The Leaf's battery pack is air-cooled, resulting in cells reaching temperatures that are far too low or high to operate efficiently in exceptionally cold or hot climates.

    Tesla's battery pack is both cooled and heated by a liquid thermal management system, maintaining cells at their optimal temperature, regardless of climate.

    Active thermal management of the battery pack is how Model S maintains its range in cold weather. It does degrade, but not by 50%.
  • VivekGowri - Monday, February 18, 2013 - link

    So, I didn't really want to speculate on the actual range effect on the Tesla would be in numerical terms, which is why I just left it as "the numbers will be different for a variety of reasons". Not only because of the liquid-cooled battery pack, but also because the heating element would likely be a lesser auxiliary load relative to the powertrain energy consumption when compared to the Leaf. Now, with that said, the principles are exactly the same. Reply
  • flyingpants - Tuesday, February 19, 2013 - link

    But you did speculate on the actual range effect on the Tesla. On page 3, paragraph 1, you said "In cold or near-freezing weather, with the heater running, I would not be that surprised to see range fall to something in the 180 mile region."

    That's a 32% drop. Why make up numbers? Why not instead find someone (anyone, maybe a Tesla forum user) who has actually done a mileage test at 20F?

    Why does the title of the article mention the "Model S", and all the data is about the Leaf? This is misleading at best.

    Doesn't Anandtech generate over $1m/yr in revenue? Since you and Anand both agree EVs need more/better testing, why not take the initiative and actually test a Model S yourselves?

  • mtwardochleb - Tuesday, February 19, 2013 - link

    Yes, you did speculate with hard numbers exactly where flyingpants said. Why?

    Also, if you're able to acknowledge the effects of active thermal management and the smaller relative load of the heating element in such a concise manner in the comments, why can't you mention it in the article?

    What principles are the same? We're now talking about a battery pack that's actively managed, trading the temperature-based efficiency loss for a small heating loss, and a smaller heater relative to the motor (which draws an even smaller fraction of available power compared to the Leaf thanks to the battery operating more efficiently), so the Model S is operating on an entirely different range vs temperature curve. If you're saying that aerodynamics and friction remain the same, of course, but we're talking about how well the car copes with cold weather, and those two factors are what determine it for these cars.
  • milkylainen - Tuesday, February 19, 2013 - link

    Speaking from one who lives in a northern country and I have had fuel based heaters in my cars for quite some time now.
    An electric drive-train should be doing just propulsion and minor electric stuff that can't be done without electricity.
    Cabin heat in freezing temperatures SHOULD come from a fuel based heater. Volvo recently showed off a all electric drive-train which had solved cabin heat by using a renewable alcohol fuel based heater. Burning hydrocarbons to create heat is something fuel is great at.
    Consumption is like an eight of a gallon per hour. Charging your electric car to burn all that precious electricity to create waste heat is just stupid.
    Base heat on some renewable hydrocarbon source instead of getting range anxiety in freezing temperatures.
    That's how you combine technology.
  • Omophorus - Tuesday, February 19, 2013 - link

    My biggest beef with the whole EV thing is that Tesla LOUDLY (LOUD NOISES!!!!) proclaims that there are "no compromises" versus a regular car.

    Obviously, that's bunk. You have to completely change your driving style, your expected trip duration (especially for longer trips) and very carefully plan your route on long trips to be near Supercharger stations if you want to go any real distance.

    And, frankly, if I'm limited in where I can go, and limited in how i can drive, I really have a hard time justifying embracing EV tech. I think the infrastructure and products will improve, and the current Tesla model range is an important step in that process, but anyone who buys one as anything except a toy is completely bonkers insane (or never, EVER drives long distances).

    Most appallingly, to actually be able to use the Tesla, you can't use it. It's a "sport sedan" in the same vein as a 5 series BMW or a Porsche Panamera, but you can't do anything sporty with it if you actually want to go any real distance. If you're just tootling about locally, you're fine, but you wouldn't be able to do something like, say, leave the Triangle in NC and head out for a blast on the Blue Ridge Parkway. You'd be out of juice in the middle of nowhere and SOL. And, if I'm honest, there are very few reasons to even want to bother living in NC (having done it myself) besides the ability to spend a spring or fall day on said BRP to enjoy the sites and one of the truly fantastic roads in America.
  • Death666Angel - Tuesday, February 19, 2013 - link

    Interesting write up. Couple things though. :D
    To say: "The world of electric vehicles is still very new to the automotive industry, the tech industry, and the mainstream consumer." Is not that accurate. Electronic engines have been around for over a century. Many car companies sold electronic vehicles in the 90s. Just because some people are unaware of certain things does not mean those things are new. :)
    Most of what you said here makes me go "duh". The interesting thing in this for me is whether the journalist is trustworthy or if he has a different agenda. So the article doesn't really help me shine a light on what is going on with regards to that. :/
    What will play a role in changing the perception of EVs is when they will be charged like normal cars in 5 minutes. 90kW isn't bad for the supercharger, but it's still cumbersome. When we can refuel the electrolyte, EVs will be seen in a better light. :)
  • law99 - Tuesday, February 19, 2013 - link

    I find the argument that you just need to "change your driving style" without merit to probably half the UK population (complete guess), if not more considering the cost of the vehicle.

    The fact remains that charging is inconvenient even to those that can. I live in shared accommodation in a house consisting of two flats. There is space for 2 cars on our drive. 2 people in the house must commute 80miles a day to work. The others 4 need commute anywhere between 15 - 40.

    So if we were driving electric cars, what the hell would we do? It doesn't matter whether I have a lead foot in my 1.4 tdi... I don't have to fight for drive space to charge my car over night. Especially considering I don't know downstairs very well. There aren't charging stations on the street either... and I'm not running a cable out there. There is a house just down the road for dysfunctional and unfortunately parent-less teens who would play havoc with that idea late at night. (And I live in a *good* area)

    I don't want to extrapolate from this really, but a very real possibility is that there are more people in the world living like this. That can't just, change their driving style. And see the Top Gear review and the fact it was thrown out of court for actually being factually accurate and realise that electric cars, just aren't there yet. They can't cope with our wallets, our commutes and our living spaces.

    The best solution I've seen so far is that a fuelling station would physically replace your battery. So you'd drive in and it would be pulled out from under you and a new one would be inserted. Otherwise we are waiting on hydrogen, better hybrids or continue using diesel for long range.
  • law99 - Tuesday, February 19, 2013 - link

    I 'd like to add to this that even if the charge times come down to 3 hours... what are we to do? I get home at 6 along with my flatmate. My friends partner at 5, and my partner at 6.

    2 hours charge takes us to 9. Another to 12. I'm out of the house by 7:30 am. The perpetual juggling of charge times is going to be untenable and impractical with a potential to put a strain on relationships (I couldn't get to work because you were on the drive??? No thanks).

    The only hope would be that work install a charging station for all vehicles. Do you expect companies to make this outlay? I don't.

    My car can return 60+ mpg and cost less than £2000 to buy.
  • chipkin - Tuesday, February 19, 2013 - link

    The Leaf can be fully charged at a Level 3 station in 25 minutes, and there are quite a few in the Chicago area. For 2013, the charging time from a Level 2 station was cut roughly in half, to 4 hours from TOTALLY dead. How often would it be totally dead? Never, really... An 80% Level 2 charge takes around 3 hours.

    You should also remember that in many urban areas there are free L2 stations all over the place, so you will be picking up charge piecemeal, and are unlikely to come home with the "Low Range" light flashing.
  • muy - Tuesday, February 19, 2013 - link

    comparing an electric vehicle to something like a vw golf diesel that can do Berlin to Moskow on a single fuel tank is stupid.

    electric vehicles have way different limitations and at this moment simply can't be compared.

    if you do more than 100 km a day, liquid fossil fuel driven vehicles rule supreme.

    if you do less than 100 km a day, electric is a valid alternative.

    apples and pears.
  • Shadowmaster625 - Tuesday, February 19, 2013 - link

    So if you charge the battery to 28%, you get a range of 50 miles. Which is how far it drove when the idiot reporter charged it to 28%. Reply
  • foxalopex - Tuesday, February 19, 2013 - link

    I recently bought myself a Chevy Volt. While I admit it is a bit expensive, I like technology so this was a car that was somewhat affordable and fit my lifestyle.

    To be honest, there's no significant changes in my driving style. Since I already live in a very cold part of Canada (Northern Ontario), I was already use to plugging the car in. Normally with a gas car you need to plug in a block heater anyhow in the winter. Thou I have to admit despite the relatively slow 0-60 (faster than a prius but no sports car) it has a lot of punch due to an electric having torque right off the line. I have noticed it makes it fairly easy to speed past normal cars as you can have the petal floored and no one can tell the difference since they can't hear you either. It also doesn't impact the battery as much as I thought it would. Probably the only major change is the slightly longer stopping distance compared to my former corolla due to weight. It corners and accelerates better probably due to traction control.

    As far as weather, the car's mostly unaffected because the gas engine will kick in when it gets too cold for the battery to maintain itself. The only time I've seen weather really affect the volt is when it bottoms out to less than -4F and you didn't bother to plug the car in for 8+ hours. Then the battery shuts down due to extreme cold and the car becomes gas only which unfortunately makes it somewhat sluggish. But to it's merit, a gas car left in those conditions is about the same, a diesel probably even worse. Thou I'll admit one hilarious change is that when it is warmer, I am tempted to drive it for fun as a pure electirc.

    I don't think pure EV's will reach mainstream unless battery technology significantly improves which will probably take a decade or two at least. The only viable technology I've heard of are induction based charging systems where your car charges as you drive. Until then I think a plug in hybrid like electric with a huge battery like the Volt is your best compromise.

    I think this is why the Volt won so many awards and is highly rated by their owners including myself.
  • humbi83 - Tuesday, February 19, 2013 - link

    As I see it there are 2 main things to the ICE vs EV debate.
    1. how much energy you can store in a cubic cm
    2. how fast you replenish that energy.

    1. It's complicated, nature is very good at getting stuff optimized. But please be aware that it had billions of years to do it. In the end we'll be able to copy that and say that it was a great discovery. I would say that petrol can be considered as a very convenient battery. Even nuclear is still our way of bowing down to the laws of nature. But for the moment we are working on it.

    SO, if 1 is not our main forte point, than at least we should try to replicate the delivery method. This brings us to the 2nd point:

    2. At least we should try to have a way of topping up that is on par with the current petrol delivery method. So MAKE IT LIQUID. You go to a "battery" pump and simply replace the old juice with the new one. Collect it and recharge. Do this in a centralized way and we are set. Now this is not concept but already in development. I see it coming in the near future.

    I think this makeshift way of charging at home is not the future, you cannot & should not plan per individual. We need to have some special, centralized way of handling this. Some big charging station that gets old juice and delivers a newly charged one. In this way you can scale & make use of delivered pow 100% of the time and not produce it "just in case" 10k ppl try to charge at the same time. You basically average the consumption and normalize the peeks to a manageable constant. In this way you can also plan your power infrastructure accordingly.
  • humbi83 - Tuesday, February 19, 2013 - link

    Oh .. let's not forget fuel cells. NASA has been using fuel cells for the past half a century. They have 60~70% eff + electric motor 90-99% eff resulting in a combined 54->70% eff. Much better then current power trains. Reply
  • Doug_G - Tuesday, February 19, 2013 - link

    I have driven my Model S on several road trips in very cold temperatures - down to 0F - and have done 190 mile legs with a 20 mile safety buffer still remaining. In extreme cold I do recommend keeping your speeds moderate (say 55 mph) and using the "Range Mode" for the heating system (still plenty warm enough).

    Other handy tips for cold trips: you want to do a "Range Mode" charge just before leaving, so the batteries are nice and toasty. Since you can continuously monitor the projected range, I try to drive to maintain a 20 mile "safety buffer" compared to the GPS display. If you're doing better than that, you can speed up; if worse, you should slow down a little.

    Of course 99% of your driving is "around town", and for that the Model S has plenty of range to spare - you don't even bother looking at the range display. You plug in when you get home, just like a cell phone, so every morning you have a "full tank" and can blast around town with no concern for range whatsoever. You don't need any charging infrastructure except a 240V plug in your own garage.
  • BoloMKXXVIII - Tuesday, February 19, 2013 - link

    All this talk about heating, but I live in the south where A/C is more important than heat. How much does the A/C impact range? Also, when you have 200 - 300 mile range, who is really going to have range anxiety? Most families have two cars. One pure electric seems doable for most families. I for one would love one once the prices get a bit more realistic. I will keep my full sized truck for hauling and long trips. The EV will get 90%+ of all the mileage. Reply
  • alpha754293 - Tuesday, February 19, 2013 - link

    Are you a mechanical engineer or an electrical engineer (by training)? Just curious.

    By "data cells" are you referring to data points? Or is that how many channels you're running? (2 million seems a little excessive if thats the number of channels you're running...)

    I forget. Is UDDS same as FTP95?
  • alpha754293 - Tuesday, February 19, 2013 - link

    from the car makers perspectives - a lot of traditional car makers don't really know what to do with an EV. They don't really know how to build 'em, test 'em, etc. because a lot of them aren't dependent on heavy use of steel for example (a lot of are build with aluminum and other lighter metals, some of which have not been fully characterized yet).

    New joining and fastening methods, new manufacturing methods -- we have a REALLY good graps of what to do with steel. We know that stuff like the back of our hands. But aluminum, and/or magnesium.'s anyone's guess at this point.

    Same thing with battery/EV modeling and development. In fact, the rate that battery technologies have been changing is MUCH faster than the rate that the internal combustion engine has been changing when IT first started.

    Don't be surprised if in the next few years, there's going to be a HUGE hiring phase pretty much at all of big (and small) auto makers for people with SOME (any) kind of EV experience as the need and the demand for people who know ANYTHING about EVs is going to be needed to answer some of these questions.

    Right now, a LOT of them are just "tweaking" their existing procedures and methods (which are often developed from steel/ICE cars) and adapting them to "work" (barely) for EVs in their various flavours.
  • rikulus - Tuesday, February 19, 2013 - link

    This was a very informative article, much appreciated. That a lot of energy is used to heat the car had crossed my mind, nice to see the numbers.

    I do get the impression from some quarters that running an electric vehicle in cold weather is inherently less efficient for the batteries. I would love to see the same test results without the heat on - not everyone needs their car set to 72 degrees. Maybe heat off, or set to 60, or just seat warmers or something.

    If the loss of range is just due to how warm the car is kept, people should know that. Maybe cars could be better insulated.
  • name99 - Tuesday, February 19, 2013 - link

    "The mechanically-driven heating elements in conventional vehicles add another 5% or so in terms of mechanical efficiency loss, while obviously the electric heater in the EV is far more costly from an energy consumption standpoint even though it doesn’t increase mechanical losses at all."

    Two questions:
    (a) My understanding was that heating for a gasoline engine cost essentially nothing because you basically diverted hot air that was flowing over the engine into the cabin. Why do you need heating elements?

    (b) Is some sort of heat pump not feasible in an electric vehicle? I honestly don't know the answer to this. Maybe, because all you have to work against is the air outside, it simply isn't feasible? (As opposed to a house, where you have the thermal inertia of the earth below the house). Or maybe the weight of the entire system, pumps and working fluid and such, makes it not a win all things considered?
  • pandemonium - Wednesday, February 20, 2013 - link

    (a) Not to say that an electric heater is needed for a combustion engine per se, but in translation of energy consumption by comparison between combustion and electric, there's still a factor of demand on the system to get that heat to the cabin (the noted ~5%). This is the most important part of that quoted statement to focus on, "in terms of mechanical efficiency loss."

    (b) A heat pump - as it stands today - by itself wouldn't function correctly for an EV. There isn't anything constantly moving mechanically on an EV (transmission, wheels, drivetrain are only when the car is in motion). When the vehicle is stationary, the pump would need to draw heat from something, and given the fact that an electric motor doesn't produce much heat (especially when compared to a combustion engine), a traditional heat pump wouldn't be sufficient in this case when the vehicle is stationary. A heat pump could possibly supplement an electric heater's function by way of water->air (think radiator surrounding anything mechanical), but the effectiveness may not be worth the weight and electric energy consumption of the pump itself.

    There's certainly consideration in the works for advancing heat pump elements for EVs. Example:
  • cmart - Tuesday, February 19, 2013 - link

    I chuckled a little when I saw that the testing went all the way down to 20F. Here in Northern MN, we average significantly colder than that for three months out of the year. Our average January temp is 11F. Reply
  • pandemonium - Wednesday, February 20, 2013 - link

    I could definitely get used to reading automotive tech articles like this on AT. The first of hopefully many more to come! Thanks. :D Reply
  • jameskatt - Wednesday, February 20, 2013 - link

    The Tesla needs a small gas heater to warm up the battery or cool the battery to help restore full mileage. This can be smaller than the generator needed by the Volt. Subsequently it would use a lot less gas or other fuel. Reply
  • Wardrop - Thursday, February 21, 2013 - link

    Bring on the graphene super capacitors...
  • Steven81 - Sunday, February 24, 2013 - link

    It's rather bizzare that companies that go to all the engineering lengths to built an EV still have such a big trouble in finding a fitiing way to refuel. There are only two ideas I can think of "swift recharge".

    One, when my phone dies I rarely charge it, it's such an inelegant way to go, instead I have precharged batteries and pop them into place (and I put the "used" battery to recharge). Something similar can well happen to these cars. Having replaceable batteries and all fuel stations would do would be to pop a precharged battery in place. Simple...

    One even more elegant way would not even require fuel stations in place but would certainly need great infrastructure (which pushes it in the " not directly doable" territory). Having roads which would in essence recharge your car through your wheels' contact with them (an alternative form of the "pantograph method" that trains already use) would do the trick.

    The idea that EV should be clones of the petrol cars that we use for more than a century is ridiculous at face value, and the ideas above are not even that ground breaking or hard to be thought...

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