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I'm ready for Tesla to do a step change on SuperCharger power/energy delivery

Discussion in 'Charging Standards and Infrastructure' started by HillCountryFun, Jun 8, 2016.

  1. HillCountryFun

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    We have announcements like this recent one:

    Electric Vehicle News: CHAdeMO Announce 150 Kw Supercharging Protocol

    And we have the SAE J1772 Combo which has a proposed DC Level 3 and may support 240KW.

    Finally, we have JB saying, in the past, that he expects Tesla to get the SuperCharger cycle times down to 10 minutes and maybe 5 minutes:

    Tesla Says Sub 10-Minute Supercharging is Possible - Inside EVs

    So, with all of that, I'm ready for Tesla to do another Step Change on delivery power!

    What might be required?
    • New hardware in the vehicle?
    • New SuperCharging hardware?
    • New Software?
    • Bigger Distribution service?
    • Will we have to wait for the Model 3 to see the step change?
    Come on JB, time for you to take to Twitter and drop some hints!!
     
  2. AEdennis

    AEdennis Active Member

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    At 5 minutes that would make SC equivalent to folks' reported real world experience with the battery swap station at Harris Ranch as it was deployed during the test period.
     
  3. Saghost

    Saghost Active Member

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    It's not going to be easy.

    As I understand it, in the lower part of the charge you're up against the safe current limit for the connector - meaning that the only ways to increase the power flow are a bigger connector, active cooling of the connector, or higher operating voltage (this last would require a battery pack change most likely.)

    In the upper range, you're limited by the pack's ability to safely accept a charge, which makes it doubtful the there's anything that can be done to accelerate this portion safely (if you knew the exact chemical state of charge and exactly how many electrons were flowing somehow, maybe you could drop in higher voltage with a sudden cutoff when it reaches nearly full capacity? AFAIK that's never been done, and I don't know where you'd develop the information needed to do it...)
     
  4. apacheguy

    apacheguy Sig 255, VIN 320

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    The cells generate less heat when charged at higher SOC. Thus there is room for improvement in Tesla's taper algo, but in my experience it charges fast enough as is. Also, the 120 kW is likely an upper limit of the cells. Maybe they could push it and go to 135 kW but certainly nothing more.

    Remember that just because there is a new protocol that supports 150 kW delivery, that does not mean any car will be capable of accepting it. Regarding the 240 kW output, I'm extremely skeptical that any manufacturer in the next two years or so would be able to sustain that.
     
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  5. digicool

    digicool Member

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    As more and more Tesla go on the road, we are at the verge of SCs getting to full utilization. What I see as a immediate need is to have all stalls of a station deliver full power rather than sharing in pairs. This seems like a low hanging fruit.

    Reminds me of the day when sometimes I used to wait in lines for upto 15 mins to fill up my ICE (5 mins) at Costco.
     
  6. Rocky_H

    Rocky_H Member

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    When I hear this I kind of think, "No, don't waste time on that yet." I still think Superchargers are beyond fast enough for me, but there are still several places in the U.S. that really need stations built. I would rather have several more stations in more places than for them to spend any of that money on upping the speed of existing ones.
     
  7. TaoJones

    TaoJones Beyond Driven

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    Fear not. We're nowhere near full utilization from a whole network standpoint. At best maybe 3% in the US in areas of density are impacted at peak times. 97% tumbleweeds still. Remember that most owners don't use SCs and most Model 3 owners probably won't either.

    I used to wait 20-25 minutes at a local Costco and then still had to pump the gas. Now I turn right at the same light, plug in, and have a spinach salad at the host property once a week.

    Faster charging would be nice but what would be even nicer is an effective nag to get people to exit the space when their charge is complete. Not 15 minutes later. When it is complete. No amount of faster charging will overcome an ICEd SC and that's the present problem in areas of density. Not "locals" not livery, but ICEing by our own.

    It would almost be worth the money to start a Kickstarter campaign to raise the money for Tesla to outsource develop of an app/firmware mod such that a car that remains in a stall after charging is complete would first text/email/call the app (all 3 at once), and then 5 minutes later would cause the car to emit unpleasant noises, followed by an audible "My owner is an asshat - please call the local police or a towing company so that I can be removed from this space immediately." The voice would of course be that of C3PO. Whether from Star Wars or Spaceballs, well, take your pick :).
     
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  8. Rocky_H

    Rocky_H Member

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    There, I fixed that for ya.

    I think that's sort of little bang for the buck. The pairing is really pretty brilliant in cost of equipment usage. Even the paired stall starts off at a pretty decent CHAdeMO rate in the worst case, and goes up within the first 5-10 minutes. I think Tesla and we drivers would be much better off putting in those extra stacks of chargers at a new location somewhere within 10, 20, 30 miles of the places that are getting crowded. I used to be irritated by that idea when the rest of the country was empty, but it is definitely the best way to alleviate congestion and make the network better.
     
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  9. digicool

    digicool Member

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    Thanks for the fixes Rocky. I fully agree that a bunch of stalls probably see just 1 or 2 spots occupied at any given time. But supercharging can only live upto its claim when most drivers are on the road and wanting to charge. As you stated most Tesla drivers only use the SCs rarely and I would want to bet a bulk of them do roadtrips around holidays. That would mean a bulk of the SC experience would happen in a short period. And that is what will account for the overall quality rating of the experience, not the small minority that use them regularly.

    While it is true that having more stalls would certainly alleviate the issue of having to wait to charge, charging faster improves SC utilization at peak times. If I could only wait 20mins to get a reasonable charge as opposed to 40 mins (at half rate) for the same charge, I will not even step out of the car thus avoiding ICEing altogether. Again, installing a new station would be so much more expensive and time consuming than connecting all As and Bs on separate circuits - the low hanging fruit.
     
  10. Saghost

    Saghost Active Member

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    It really depends on where the biggest limitation is. What you're proposing doubles the equipment cost for the most expensive parts and may require a bigger transformer in exchange for a twenty or thirty percent increase in throughput at the existing location.

    With the same new equipment, you could almost set up a second site nearby - but then you'd pay another set of construction and licensing costs.

    If the equipment costs are anywhere near the permit and construction costs, building a second site makes much more sense - you get infrastructure redundancy, more overall throughput, and better options/coverage for various users for a little more money.

    If the chargers are a fairly small part of the cost and available in surplus of needs, then what you're suggesting would make sense if the transformer can take it.
     
  11. digicool

    digicool Member

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    Tesla will know whether this is little or lot more money.

    I will come find you in 2 years, when you post a message saying that Model 3s crowding the SCs that your Tesla premium experience is no longer premium ;)
     
  12. brianman

    brianman Burrito Founder

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    A likely unpopular but effective option...
    • Stalls 1-2 are reserved for "legacy" cars.
    • Stalls 3-N are reserved for self-parking cars that move themselves out of the way automatically when a driver-specified SOC is reached.
     
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  13. TaoJones

    TaoJones Beyond Driven

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    I'll make you a bet similar to the one I proposed to sorka that he failed to accept after continuing to profess the usual FUD/doom and gloom/handwringing/exclusionary rhetoric about "locals". A beverage or some other something if in 24 months from today the experience is not 95% fine at 95% of SCs due to Model 3s.

    June 10, 2018 - up for it?
     
  14. Rocky_H

    Rocky_H Member

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    But isn't this really straightforward? The charging speed and utilization ratio isn't generally the problem. It's the stalls being full. More stalls = less waiting for everyone.

    Huh. OK, that is actually kind of interesting. If everyone's charges are almost always 30 minutes or less, I could see that kind of taking away some of the motivation to leave the car there for a lot longer, blocking the spot. By the time you walk somewhere and walk back, you're almost done, so not much point in doing much in between. Whereas if you are starting off slow and think it's going to be at least an hour, then why not take your time and do something more involved for two, two and a half hours?


    Yeah, we don't know the relative costs. I just have a hard time with that because the sharing is such an amazing, brilliant, and cost-effective use of the hardware. But, I have never been paired, so I don't really know the experience.
     
  15. digicool

    digicool Member

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    The second time I used the supercharger ever for my Model X (last memorial day weekend) at the Burlington SC, WA, about 6 cars were charging / 8 when I pulled in. And I kept seeing Teslas pulling in and pulling out keeping upto 7 stalls occupied constantly. I recouped about 90 miles in 50 minutes. Not terrible because we decided to walk to the nearest starbucks to grab a coffee (about 30mins round trip) but not exactly a "Super" charger experience that Tesla advertises. A geek like me will have no problem with this but my wife was not exactly happy about that.
    Agree again, it is brilliant engineering but it compromises the experience which is a major component of driving the Tesla. If I wanted to do cost-effective, efficient EV driving, I should still be driving a Leaf.

    If 6 months worth of Model 3s got delivered (roughly 250K, or lets say 125K on the road) by then, I will take that bet. If the $100K car owners find justification to use free superchargers, $35K car owners will have more reasons to do so given the smaller batteries.
     
  16. Saghost

    Saghost Active Member

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    Tesla certainly does know how the costs break down - and the fact that aside from site with odd numbers of stalls they have continued to split the chargers suggests to me that some combination of the cost of chargers, the availability of chargers or the transformer capacity is a big factor in the installation plan.

    I'm also disappointed with the way you chose your quotes in this post, which makes it appear that I am making statements I didn't make, asserting things I don't actually believe are true. :(
     
  17. deonb

    deonb Active Member

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    Tesla don't necessarily need to increase the Supercharger speed. They just need to increase the battery size.

    A battery size that gets to the point of being able to skip a Supercharger (I think 120kWh will do that), will drastically reduce Supercharger usage.

    And a 120kWh battery won't take significantly longer to charge to 90% than a 75. Maybe an extra 10 minutes, but then you get to skip the next 40 minute charge.
     
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  18. digicool

    digicool Member

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    Did not mean to. But I would think someone will read your post to infer what you believe rather than reading my quotes of your post to do so. Also, I just quoted the statements you made, did not try to paraphrase.
     
  19. apacheguy

    apacheguy Sig 255, VIN 320

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    I'm not sure that's necessarily true. The 90 already takes 5-10 minutes longer to reach 90% compared to the 85.
     
  20. deonb

    deonb Active Member

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    True, there are different curves for different chemistry.

    But if there is a theoretical chemistry of a 120 battery that curves like the 85, where you can charge it to 50% at 135kWh then you have:

    0 to 50% of 85kWh = 18 minutes
    0 to 50% of 120kWh = 26 minutes

    Note that this is the theoretical max. We know through experience that there is a small curve even before 50%, so the 85kWh in actuality takes about 22 minutes to get to 50%. And as such the 120kWh will take 30 minutes.

    But above that you're purely chemistry limited (on a 135 Supercharger anyway), so then it doesn't matter how big the battery is - it will charge at the same rate as a function of percentage/minute. Which means the typical ~18 minutes to get from 50% to 80% etc.

    That means:

    80% charge of a 85kWh = 40 minutes
    80% charge of a 120kWh = 48 minutes.

    For similar charge curves.
     

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