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Optimal Battery Size and Driving Habits

Discussion in 'TSLA Investor Discussions' started by Auzie, May 27, 2014.

  1. Auzie

    Auzie Tree Hugger Member

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    I would be surprised if we ever go that way, ie backwards. In some remote future years, I would expect battery technology to substantially improve, making today's energy densities a fraction of future cells densities.

    As the demand for batteries increases and more resources are put into batteries development, the technology advancements might start to follow Moore's Law.
     
  2. FANGO

    FANGO Active Member

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    #2 FANGO, May 27, 2014
    Last edited: May 27, 2014
    How is that backwards? Selling cheaper cars to a populace who is increasingly aware that long ranges are unnecessary, particularly as superchargers get installed in enough places that long ranges are even more unnecessary than they currently are, that sounds like forward movement to me.

    Battery sizes will not continually increase - and the public shouldn't be made to think they will, as it will slow adoption while people wait forever because nothing is ever "good enough." Technology advancements for batteries do not and will not follow Moore's Law, but they do follow a mini-Moore's law, but very mini - 7-10% per year, as has been discussed above. This will be focused almost entirely on cost and weight improvements, not range improvements. Well, small EVs will increase range, and the Model S will decrease cost (and turn into a Model E, etc.). But even the first part of that isn't necessarily true, since the new Spark EV actually has a smaller battery than the original one (but same range, because it's been made lighter).

    In fact, expanding on my previous comment, I bet they even have a design for a 40kWh battery pretty much finalized by now (since they made those packs for the RAV4 anyway...), and if there's ever a demand problem, they'll roll it out. But like I said I wouldn't expect this to happen for a few years, so it may not ever be necessary.
     
  3. Auzie

    Auzie Tree Hugger Member

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    I consider going from 60 kWh to 40 kWh backwards.

    Time scale that I had in mind is decades, as I believe that Tesla will be production constrained for at least a decade.

    Improvements in battery technology that follow mini-Moore law may be sufficient to rule out going back to 40 kWh in 10 years time.

    I would expect mini-Moore Law to start resembling Moore Law when battery demand for cars goes up substantially.

    The only driving force for battery development today is the demand for phones and laptops batteries and similar, mainly for power backup. Batteries in these devices are not so relevant for their performance. Batteries in cars are critical for the cars performance. The battery technology is the key technology for ev cars, unlike phones and laptops.

    Once demand for car batteries grows I expect huge increase in R&D of battery technology. I also expect to see emerging race of competing battery technologies.
     
  4. JRP3

    JRP3 Hyperactive Member

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    Not only would a 40 S be going backwards it would be a lesser product than the Gen3 car. Makes no sense to do a 40 now, especially since Elon crapped all over it. Not going to happen.
     
  5. roblab

    roblab Active Member

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    This continuing argument about what is necessary or not does not sink into my little brain. I don't get it. I think of gas cars.

    They are cheap.

    Long ranges are "unnecessary".

    "Super(gas)chargers" are everywhere.

    WHY, then do gas cars come with a 300 mile range?

    People may not need 300 mile range, but it's the minimum we think we need. If YOU like driving with half that, and like having to stop at superchargers, or gas stations, twice as often, you are the rare one. That's precisely why 40 kWh batteries are not being made. The demand is not there.

    If you want a cheap electric with no range, there is the Leaf, the Spark, the iMiev, or you can go with Volt or BMW i3. Tesla builds cars that are NO COMPROMISE, and, yes they are more expensive.

    But Tesla's competition is not Nissan or Chevy or Mitsubishi. They compete with BMW, Porsche, Mercedes. And I'm sure there are disadvantaged people who think it is their right to have those car makers make a high quality car for them at dirt cheap prices. But it doesn't happen.
     
  6. tentonine

    tentonine Member

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    #6 tentonine, May 27, 2014
    Last edited: May 27, 2014
    While people thinking that they need 300 miles may be part of the argument, I think it is more to do with how often the cars need to be filled up: for most people, a supercharger visit will be an occasional thing on an infrequent journey, while they can conveniently plug in the car at home every night for the regular commute. As a gas car cannot be filled at home, most people would find it inconvenient to have to stop to fill it up more often just for regular local driving.

    In conclusion: gas cars benefit from large tanks even when they are never used on long journeys, whereas EVs have little benefit from large batteries if they are never used on long journeys.
     
  7. FANGO

    FANGO Active Member

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    Gas cars come with 300 miles because the cost of adding a larger tank is negligible. The cost of adding larger batteries is not. Also, they come with larger tanks because people don't go to the gas station every day, because going to gas stations sucks. EVs don't go to gas stations, so there's another reason not to have a huge tank. So I will ask you a similar question: WHY do gas cars only come with a 300 mile range? They could come with a 1,000 mile range, and they wouldn't cost much more at all. Why haven't gas tank capacities been increasing steadily over time, if gigantic "range" numbers are so important?

    Like you said, people do not need 300 miles. They think they need 300 miles, but they don't. They think this because they've been told by traditional auto companies that range is important, and by EV advocates who don't understand that they're arguing against their cause, and they will continue to think this if they are told by EV companies that ranges will continually increase (by, for example, the companies continuing to offer larger-range products and cut out smaller-range products). Which is why a 40kWh battery would be a forward step, not a backward one, because as people make the forward step of realizing they don't need 300 miles, and as companies show them that range won't increase forever and that's just fine because range is already well beyond what all but the biggest outliers need, they will realize they can purchase a smaller battery and be just fine.

    The only way in which I'm the rare one is that I seem to be the only one who has read any statistics on people's driving patterns. People do not drive 300 miles in a day, and they do not drive 160 miles in a day. The proportion who do is insanely small. We're talking .1% or less. 40kWh batteries are not being made because the company is supply-constrained, and is focusing on higher-margin vehicles. I guarantee you that if cars were sitting on the lot unsold, Tesla would not have discontinued the 40kWh battery.

    Lots of people want a cheap electric with no range, which is why Nissan has sold over 120k Leafs. And they have not been as focused on it as Tesla has, yet their sales numbers are much higher. Why is that? Because a cheaper car sells better. And if a 40kWh car is cheaper than a 60kWh car, it will sell better. Tesla doesn't need to do this because they don't have a demand problem, which is why they can focus on high-margin cars and customers which is the right thing to do short-term business-wise right now, but if they ever do have a demand problem, they will need to. BMW and Mercedes make lower-cost versions of cars, they make cars starting in the 30k range, and they sell a lot more of those than they do their more expensive cars. Manufacturers know that cheaper cars sell better, so they will always want to make their cars cheaper. This is why car kWh capacities will not increase forever. It will always cost more to have a larger battery than a smaller one, no matter what technological improvements we see. And this will be a non-negligible amount for at least the next 30-40 years if battery improvement trends continue at the fairly rapid pace they have now.
     
  8. AudubonB

    AudubonB Mild-mannered Moderator Lord Vetinari*

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    Fango: Please stop transposing your driving habits and those in your immediate circle onto others. Your "We're talking 0.1% or less" is absurdly inaccurate. Although I know I am somewhat of an outlier here, I'm not that far off.

    300 miles gets me to town. That's all. It is the utmost in minimally acceptable range - in itself, it means a grocery trip is an overnight debacle. Less than 300 miles...and I can't even get to town.

    Thank you.
     
  9. Auzie

    Auzie Tree Hugger Member

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    Wow 300 miles from town. I think I would stop buying groceries if I were that far:wink:
     
  10. Lessmog

    Lessmog Member

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    In agreement with AudubonB. I may not drive 300 miles every day, but when I do (about every other month) I do it in one day, to get to a work place. Wouldn't do to be late for work, and it wouldn't pay to have to get a hotel along the way just to get paid.

    So for me too, 300 miles range just about takes me to work (if driving carefully, without snow etc) but without any decent way to charge once there. One gas station offers two 230V16A single-phase outlets for max two hours at a price (unless their own EV occupies them).

    That was one reason for my hesitation to get a Tesla; another was the lack of fast charging en route. This may change soon, but not soon enough or with enough certainty, so I cancelled my order. :-(

    It hurts to be one of THOSE 1%!
     
  11. Familial Rhino

    Familial Rhino Endangerous Herbivore

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    People's driving statistics don't determine people's buying decisions. Perception and habit do.

    For instance, people complain constantly that their electronic devices are too complicated to use. You'd think they want simpler devices, and yet, every market study out there shows that electronics buyers almost always go for the products with the longest list of features, even though they never use most of them.

    In my experience, range is the number one question that comes up every single time the subject of electric cars comes up with the average person. This single issue really is top of mind. You can argue that it's irrational until the cows come home (not that I'd agree btw, I'm one of those who wants a longer range and I'll gladly pay for it when the time comes), but it simply doesn't matter that it's irrational. For the foreseeable future, it will be the determining factor in making people choose one electric car over another, all else being equal. For competing manufacturers, it will be the killer feature to advertise, just like in the past you had to push the MHz factor to sell computers. And that's why I predict that average ranges will continue to increase, technology advances permitting.

    This discussion belongs to another thread, anyway.
     
  12. bonaire

    bonaire Active Member

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    This is what statisticians call "an outlier". Cities with millions of people have people with very similar driving scenarios. "Common Man" is what some call it. Up there in AK - you are a small statistical anomaly. You sure could use an EV with range extender. Volt perhaps or whatever. That kind of situation is great for your nearby routines and then the long trips also. Maybe a 100 mile EV with a nice range extender and 20 gallon gas tank. In AK - something like the Via Motors V-Trux would be pretty cool.
     
  13. Norbert

    Norbert TSLA will win

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    The "best" range vs "cheap" range discussion belongs somewhere else (long-term strategy). Besides, Tesla stopping production of the 40 kWh speaks for itself, it's min 200 mile range for Tesla. That's been clear for a long time now. Otherwise, it's Leaf and i3 with which Tesla isn't going to try compete in the "cheap" category. Tesla is about cars that are better than ICEs, not about cheap eco boxes.
     
  14. FANGO

    FANGO Active Member

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    #14 FANGO, May 27, 2014
    Last edited: May 27, 2014
    You're probably right that it's absurdly inaccurate, I should have said something like .01%.

    http://research.microsoft.com/en-us/um/people/jckrumm/Publications%202012/2012-01-0489%20SAE%20published.pdf

    The number is small enough that it is literally off the charts. Note, by the way, that the data presented here is done via histograms, not "average" driving distances, so you can see which proportion of cars are driven any particular number of miles per day. Thus outliers are included in this data, and not just glossed over as they would be with a single average number. This data was also taken in 2009, when people drove more miles than they do today (miles driven has been decreasing for about a decade now, in the US).

    Like I said, I base this on statistics, not on anyone's "circle." I've pointed this out every time I mention it, and posted these statistics many times, and even having posted them I'm still the only one who seems to have read them. The statistics show that people simply do not drive 300 miles in a day. And if you think it's normal for people to drive 300 miles in a day, then you are the one transposing your driving habits onto others. In fact, I don't think I've ever mentioned my personal driving habits any of the times I've discussed this, and yet you just have yourself, while accusing me of doing so.

    - - - Updated - - -

    This is exactly why I said that EV advocates focusing on promising infinitely-increasing longer ranges is detrimental to EV adoption, and why it would be a step forward for companies *not* to continually increase range. Because when customers see that, they think that range will continue to increase, and that range is the number one most important thing. It's not. That's why when this does come up every time with the average person, I usually gloss over it with some noncommittal answer, to show that I am not very concerned about it, and move on to talking about the things which are more important.

    You're probably right that average ranges will increase, only because I think the low-range EVs will have increasing ranges, because there is a rational reason to want more range out of them. There is not a rational reason to want more range out of the Model S, particularly given superchargers, for all but the smallest outlier of consumers.

    By the way, notice that all of this conversation is ignoring superchargers. More superchargers = less range needed, not more.
     
  15. Familial Rhino

    Familial Rhino Endangerous Herbivore

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    #15 Familial Rhino, May 27, 2014
    Last edited: May 27, 2014
    I never encouraged anyone to wait for longer ranges, nevermind promising anything. I do, in fact, point them to statistics like the one you cited, and it does make people ponder, however most say they prefer to wait (for instance they wouldn't buy a Leaf with its current range.) At that point, for me to tell them they don't know what they need would be presumptuous.

    To say that advocates influence people's priorities is absurd. They tend to decide for themselves what it is they need, they don't rely on EV advocates to tell them.

    Edit: We've cross-posted. I've now seen the last part of your post. I agree that there is no overarching need for ranges longer than the top range Model S, but if they ever offer it, I'm sure there will be a market for them. There is no rational need for a BMW 7 when a Buick will do, and yet people aspire to buy them.
     
  16. FANGO

    FANGO Active Member

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    I don't think it's absurd at all. Early adopters and opinion leaders can set the tone for society's take on a product, absolutely. If early adopters all wrote blogs about how the thing doesn't work because it doesn't go far enough, and then media got hold of this idea and reported it over and over, that would certainly chill the general public's feelings about the car. The Model S does well because it's universally loved by the early adopters, and word-of-mouth, the most valuable form of advertising there is, has been phenomenal. The same holds true for the Leaf and Volt. People generally love their EVs, and that's driving demand.

    But I did say in my other comment earlier that manufacturers have an influence on it. Traditional manufacturers want to talk about range as much as they can, because it's in their interest to play up the "disadvantages" of EVs. Or to create the perception of a disadvantage when the thing in question is actually an advantage (not having to go to gas stations, having the car be full when you leave the house).

    If Tesla's official mission is to expedite EV adoption (which it is), then Tesla needs to be careful about making the general public feel that range is the most important question about an EV. I think they do a fairly good job about this, and the focus is largely on making a great high-performing car which just happens to be electric, and which can get anywhere because of the supercharger network, regardless of what "range" car you get. But this is why I feel like discontinuing the 40kWh was a step backwards, because it sends the message that the 40 wasn't "enough." I understand it from a business perspective, particularly now because of the supply constraints, but it does not aid the case of greater EV adoption. It could well make the lower-range but affordably-priced EVs look inferior, such that people may put off buying decisions for a few years. Luckily, the Leaf is still selling very well, and it seems people haven't been too put-off by it. But it needs to sell better. We need more EVs on the road now, not years from now. We need to stop burning oil.
     
  17. ckessel

    ckessel Active Member

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    If folks were fine with shorter range, the LEAF would have exploded in sales. And/or the 40kwh Tesla would have had a huge demand relative to the other battery sizes.

    The market seems to have spoken pretty definitively in both cases: small batteries won't sell. Trying to convince people that what they feel is important (range) isn't really important is a lost cause. Even if they accept the argument, they're not going to feel confident about it internally and folks won't buy a car they don't feel good about.

    And with most folks, you're not even going to get them to really absorb your argument, but more likely will get them doubling down on their stance as an instinctive response to being told they're wrong to feel as they do.
     
  18. dha

    dha Member

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    I'm not following the logic that the S 40 was discontinued due to supply constraints. You'd think that given a constrained number of cells, they'd want to ship as many 40s as possible to maximize the number of vehicles being sold?

    I'm included to believe Elon when he says there was simply no demand for the lower range model.
     
  19. FANGO

    FANGO Active Member

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    #19 FANGO, May 27, 2014
    Last edited: May 27, 2014
    The Leaf has exploded in sales. They've sold 120k worldwide, I think. And that's from a bunch of dealers which aren't at all fully focused on selling them. And of course there are all the other low-range EVs from other manufacturers, if we're just doing a comparison of smaller batteries vs. larger ones. Compared to, what are we at now, 40k Model S? So the market seems to have spoken pretty definitively in this case: small batteries, and more importantly cheaper cars, sell better. This is not surprising. Cheaper things always sell better. The Model S is doing disproportionately well because it's *such* a good car, that is clear, and because Tesla has a much better selling strategy. And part of it is because people are (largely irrationally) worried about range, true. But if you want to just look at raw sales numbers, you're going to end up seeing that the cheaper cars sell better.

    The 40kWh didn't sell because Tesla kept pushing it back and making it completely unclear whether they would ever make the car, canceled it when all the buyers were early adopters so the orders were disproportionately skewed towards the top-end version anyway, and when they asked for a 5k deposit for an unspecified number of months from the most price-sensitive customers (those buying the base model), with no ability to lease or finance the car at the time. Of course it didn't sell well, Tesla wasn't selling it. Those who could afford the 60 jumped their order up to the 60, those who couldn't dropped out or didn't reserve until they thought it was clear the car would get made.
     
  20. Auzie

    Auzie Tree Hugger Member

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    Tesla makes more money on more expensive models
     

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