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Early Model S owners - remember the supposed Supercharger penalty? Not a problem.

Discussion in 'Model S: Battery & Charging' started by WSE51, Jan 21, 2015.

  1. WSE51

    WSE51 Member

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    Got a response today to an email I wrote to Jerome Guillen ...

    Jerome,

    I am an early Signature Model S owner and when I took delivery in September 2012, there was talk about minimizing the use of Superchargers when not required for long road trips, due to the fact that it could shorten battery life. No one seems to talk about this anymore, is it still considered an issue?

    Thanks for a great car!!

    Bill

    Dear William:

    Thank you for your message.

    The battery calculates and communicates to the Supercharger the maximum acceptable charging rate based on instantaneous current, current over time, voltage, temperature, and other considerations. This is done to maximize charging rate without accelerating battery degradation. Thus, the design of the Supercharger and the design of the vehicle/battery work together to avoid degradation such that the end user does not need to worry about it. We want our owners to have peace of mind in owning and using Model S without the need to read or follow instructions in a manual.

    I am glad to hear you and your family enjoy your Model S and continue to support our company.

    Best regards,

    Jerome Guillen I VP, WW sales and service
     
  2. AnOutsider

    AnOutsider S532 # XS27

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    I wonder if this is one of those "it still degrades, but not by as much and we don't want the public worrying about it" things. Last thing they need is for people to be worried about using the SCs that Tesla is touting as a benefit.
     
  3. RDoc

    RDoc S85D

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    That's not impossible by any means, but another explanation might be that they've changed the algorithm, possibly because of more real world data and the existence of much higher initial current from the upgraded Superchargers. All of this is speculation of course.
     
  4. mikeash

    mikeash Active Member

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    I get the impression that battery degradation is still not very well understood, and a lot of the theory around it is more guesswork than knowledge. Take for example the changes Nissan has made to the Leaf's charging. Originally they made it hard to charge to 100% to prevent degradation, but now they seem to have decided that this isn't a problem, and apparently make it hard not to charge to 100%.

    I wouldn't be surprised if supercharging were a similar situation. The original guesswork was that it would hurt, but real-world data has since disproven that. The one thing that really seems to be bad for batteries is extreme temperatures (such as getting too hot because of waste heat from fast charging), and the Model S's active temperature management more or less solves that.

    This is, of course, complete speculation on my part.
     
  5. TES-E

    TES-E Member

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    I read this as supercharging is no worse for battery life than any other form of charging.
     
  6. Panu

    Panu Member

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    According to this (not from Tesla) ultra-fast charging kills Li-ion battery quickly:

    Tesla has probably solved much of the problem with their algorithm but it's hard to believe they would have solved it completely.
     
  7. liuping

    liuping Active Member

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    Superchargers charge at about 1.4 C at their peek, but much of the time is spent at less than 1C.

    The article talks about ultra-fast charging at as high as 10C. We're nowhere near that, so I would not worry about it.
     
  8. Panu

    Panu Member

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    OK that's good to know. In the chart in that page the fastest charging is 3C.
     
  9. liuping

    liuping Active Member

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    Also, remember most of the charging is done at home, at way below 1C. For 85kWh battery owners, the HPWC charges at less than .5C and the UMC charges at less than .25C.

    The relatively few slightly higher than 1C charges while traveling should not be a problem at all.
     
  10. Panu

    Panu Member

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    Not necessarily. If you live near a SC you may want to save money by charging there daily.
     
  11. RyanT

    RyanT Member

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    It also depends on the battery chemistry. Some batteries can take well over 2C charging. Some are designed to perform well at 10C discharges. It's a balance between energy density, power density, battery life, charge rates, and discharge rates. I'm sure active cooling also plays a significant role. Tesla and Panasonic are probably constantly looking at these graphs and chemistries to see if they can improve one or more of these values while minimizing the impacts on the others.
     
  12. omarsultan

    omarsultan Active Member

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    #12 omarsultan, Jan 22, 2015
    Last edited: Jan 22, 2015
    Actually, Tom Saxton from Plug-In America has been collected a fair amount of empirical data on battery life (you should all fill out the battery survey to help gather data points Plug In America) and the Model S data looks promising - Tom did a session at TMC Connect to review initial results. His blog is here Tom Saxton's Blog

    Personally, I use a SC at least once a week and my pack degradation is minimal - S85 w/ ~44K miles will max charge to ~262 rated miles.
     
  13. RyanT

    RyanT Member

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    Do you mind me asking what you charge to on a daily basis, 60%, 80%, 90%?
     
  14. omarsultan

    omarsultan Active Member

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    Sure. On a daily basis, I charge to [email protected] Twice a week, I head into the Bay Area for work, so I max charge at least twice a week and usually end up SC-ing at least once per week. My MS is my daily driver so I cannot afford to coddle it - I know some folks baby their battery packs, but I am part of the use it hard and put it away wet crowd. :)
     
  15. Six

    Six Member

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    A degraded battery is the karmic penalty of using superchargers daily to save a few dollars but inconveniencing travelers who have to charge there :)
     
  16. Chipper

    Chipper Active Member

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    Do you have ANY evidence to support this or is it just a SWAG? Everything I have ever read indicates charging at a supercharger is equally as safe as charging on an HPWC.
     
  17. ItsNotAboutTheMoney

    ItsNotAboutTheMoney Active Member

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    #17 ItsNotAboutTheMoney, Jan 23, 2015
    Last edited: Jan 23, 2015
    You forgot manufacturing cost.

    Simplified to power density, energy density, durability and cost the saying is "Pick 3 of 4."

    Tesla sets a baseline target for durability (10 years) and power density.
    Since they use large capacities, the power density requirements are lower than some other vehicles. (They seem to limit to 4C for discharge and up to 1.5C for DC (when empty)).
    They do a lot of work with their BMS to keep temperatures controlled and even through the battery.

    With the baseline set and aided by BMS, they then focus on lowering cost and raising energy density. It seems to be that US manufacturers understood early that the use of a BMS would help them drive the cost down and extend the life of the battery. Part of that might have been reaction to the competitive car market and the extreme environments found across the country.

    Updated:
    As energy density increases Tesla I'm sure that Tesla will try to increase the maximum capacity of batteries in their cars. I'm sure Tesla would already be able to build a 200 mile mid-size, but because capacity ~ range ~ performance ~ charging mph ~ 1/C, Tesla wants to be able to sell S85-equivalent or better Model 3s and progressively higher range and faster charging cars, because the better they can make the cars, the more of the better cars they can sell, the less challenge there would be for the Supercharger networks.
     
  18. Panu

    Panu Member

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    I agree, those bastards get what they deserve :mad: (and that's my opinion as long as there are no superchargers near me!) :biggrin:.
     
  19. roblab

    roblab Active Member

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    With all of the money you save, you can start buying a few solar panels at a time, then add a few more, until they pay off (usually 6 - 8 years) and you can charge at home all the time for the same price as going to the supercharger. Then you won't get stuck waiting for a charger with all those new models coming out wanting to charge for free.

    If you had thought of this a few years ago (Like I did, way before buying Tesla) your charging could be free at home even now! Or, if you, like my neighbors, keep saying that solar is too expensive, they can't afford it, wait until the bugs are worked out, whatever, you might still be trying to charge at superchargers the rest of your life.

    Saving money happens by planning ahead more than hoping Tesla will put in a supercharger near you.
     
  20. Panu

    Panu Member

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    Yes I'm interested in solar panels although Finland is far up north and the sun is usually not shining. I've read about them for some time and will have to learn more. I'll probably post some questions to solar panel threads here. Right now my first hope is to get my S85 and the second one is to get the first supercharger in Finland!
     

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