TMC is an independent, primarily volunteer organization that relies on ad revenue to cover its operating costs. Please consider whitelisting TMC on your ad blocker or making a Paypal contribution here: paypal.me/SupportTMC

90kWh battery?

Discussion in 'Model S: Battery & Charging' started by plaid, Jul 27, 2015.

  1. plaid

    plaid Member

    Joined:
    Jul 18, 2015
    Messages:
    6
    Location:
    New Jersey
    Contemplating buying an S. So this thread is about a new purchase and I am looking at whether or not to get the 90 battery.

    What do we know (what can we speculate?) about the real world performance of the 90 battery?


    I understand the price/value. I can do that math. But I am really want to get a sense of the intangibles.


    Is it going to prove to be an enhancement? Logetivity, speed to charge, ability to not lose miles over time, etc. I am trying to determine if I am going to order a car now, do I want it?

    Is the general sense that this battery will become standard either for the X for for the S in the future (meaning the 85 and the current chemistry will go away)?

    Thanks,
    Mike
     
  2. cgiGuy

    cgiGuy Member

    Joined:
    Jul 9, 2013
    Messages:
    983
    Location:
    Sacramento, CA
    You can't put a price in logetivity. ;)
     
  3. plaid

    plaid Member

    Joined:
    Jul 18, 2015
    Messages:
    6
    Location:
    New Jersey
    I clearly can't spell either...

    /
     
  4. dsm363

    dsm363 Roadster + Sig Model S

    Joined:
    May 17, 2009
    Messages:
    18,235
    Location:
    Las Vegas, NV
    Nobody knows is short answer. 85 will likely go away is the guess. It should last longer as it simply has more capacity to lose before it gets to a level of range that no longer works for you.
     
  5. mibaro2

    mibaro2 Member

    Joined:
    Dec 2, 2012
    Messages:
    958
    Location:
    Georgetown, ON
    For your last question, I think most people here believe the 85 option will go away and the 90 will be the standard for the X.
    However, in a year or 2, they may come up with better chemistry and have 110kw battery. So how long it will stay a standard no one knows.
    IMO, the 90 would probably give you better resale value if you ever sold it.
    I didn't think I would be driving a "classic" model S a year after I bought my car. I still enjoy driving it everyday.
     
  6. TexasEV

    TexasEV Active Member

    Joined:
    Jun 5, 2013
    Messages:
    3,786
    Location:
    Austin, TX
    It depends on what your driving pattern will be. The difference is relatively small compared to the difference between a 60 and 85 (or now 70 and 85). It will likely be 10-15 miles extra range and 2 or 3 minutes shorter supercharging time. Only you can decide if that's worth the extra $3000. No one knows if degradation over time will be better or worse, but with the current batteries that hasn't been much of an issue. Overall I doubt the difference between a 85 and 90 will have any practical consequence for most people.
     
  7. plaid

    plaid Member

    Joined:
    Jul 18, 2015
    Messages:
    6
    Location:
    New Jersey
    Here is my take:

    Money: $3K is only a small factor on a $100K car
    10-15 miles of range: only a small factor and in-line with the cost
    Faster supercharging: only a small factor if (its just a few minutes)
    Battery degradation characteristics: big factor (and totally unknown)
    Unknowns: Will Tesla "release" more capacity? or some other surprise announcement?

    Conceptually I want the "best" battery I can buy for a car at this price point -- but I don't necessarily want to take on any additional risk.

    I feel deciding on whether or not to take the battery option is the big issue on configuring a new car. Definitely some unknowns.

    /
     
  8. Matteo

    Matteo Member

    Joined:
    Jul 6, 2015
    Messages:
    168
    Location:
    EU
    #8 Matteo, Jul 27, 2015
    Last edited: Jul 27, 2015
    Hi Mike,

    Listen to the 17 July 2015 conference call from 12:40 here. Yes it will become standard for S and X. They are waiting for EPA test results. Elon said they can't release EPA numbers before EPA tests the car. They did that before with the P85D. Tesla used to say "EPA estimated" range on the order page when they were selling P85D. Why not now? My guess is other car company lawyers must have contacted EPA to complain that Tesla shouldn't be allowed to sell a new model unless it is approved by EPA. That's why the 90 kWh is an option instead a different model. And that's why Tesla doesn't show an estimated EPA range for 90 models. But this is just temporary. When the range numbers are approved, the new models will appear on EPA website here. Also it is clear that either we will see a 95 kWh in 2016, or if that doesn't happen we will see a 100 kWh in 2017. This is supported by Elon's blog post:

    [Update: it was not July 2014, it was Nov 2014, I corrected the link]
    To have more perspective on this (particularly on lab level tests, small production tests etc.) I also recommend listening to Nov 2014 conference call from 17:25 here.

    In that conference call Elon gives this timeline for new cell tests:

    • 1-2 years lab level tests
    • 1-2 year small production tests.
    • mass production

    The reason why Elon talks about yearly upgrades is because the 95 kWh cells must be already in small production test stage right now. The 100 kWh cells must be in lab level test stage. On the 17 July 2015 conference call Elon explained this here at 8:39. He said:

    In other words with this new silicon there is a new path to improve cells a few percentage every year. Different versions of those cells would need to be tested in parallel at different stages. Because the 90 kWh cells have entered mass production now, it is safe to assume 95 kWh cells are at small scale production tests. There is also the July 2014 conference call from 25:23 to 27:37 here where Elon talked about cell changes.
     
  9. Saghost

    Saghost Active Member

    Joined:
    Oct 9, 2013
    Messages:
    3,026
    Location:
    Delaware
    We know very little. I do think Tesla expects to make it standard over time. To my mind, the really big unknown is longevity. The reason no one uses pure silicon anodes is the break down - the silicon shrinks and swells with each charge cycle, and it either breaks down the separator or comes loose from the external anode in relatively short order.

    Now Tesla is introducing a partially silicon anode. Will it have a partial problem like a fully silicon anode? I certainly don't know the answer. Tesla obviously believes the cells will last - they're offering it in their most expensive cars with an unlimited 8 year warranty behind it. They might be right, or they might not be.

    As much of a stretch as the car would be for me to afford, I don't think I'd take the chance for the extra 15 miles of range right now. If the improvement becomes larger, and/or we get more demonstrated history my perspective might change.

    If I were buying hundred thousand dollar cars every couple years I'd be more likely to go for it, too. :)
    Walter
     
  10. Matteo

    Matteo Member

    Joined:
    Jul 6, 2015
    Messages:
    168
    Location:
    EU
    #10 Matteo, Jul 27, 2015
    Last edited: Jul 27, 2015
    Check out this calculator: Tesla Supercharge Time Calculator - Google Sheets

    Time differences for supercharging from and to these rated miles in S85D vs S90D:
    40-180mi: 3 min difference; S85D: 32 min 30 sec, S90D: 29 min 42 sec
    40-200mi: 4 min difference;
    40-220mi: 5 min difference;
    40-240mi: 6 min difference;
    40-260mi: 11 min difference;

    Check out this other calculator: Tesla Model S energy consumption calculator between two superchargers - Google Sheets
    I recommend selecting Gilroy, CA to Tejon Ranch, CA supercharger because that will consume the entire battery. Try S85D and S90D side by side. As you see you can either consume 16 miles less rated range or you can drive 4-5 mph faster.
     
  11. Saghost

    Saghost Active Member

    Joined:
    Oct 9, 2013
    Messages:
    3,026
    Location:
    Delaware
    Where does this data come from? AFAIK, there aren't any 90Ds in the wild to have tried supercharging and developed empirical curves. I don't think we even know the full and empty voltages for certain - this is critical for calculating supercharging since the current cable limit is 330A and sets the maximum charging power.

    (I've read that silicon anode cells have a lower nominal cell voltage? Not sure if that applies to this hybrid or not?)
    Walter
     
  12. Matteo

    Matteo Member

    Joined:
    Jul 6, 2015
    Messages:
    168
    Location:
    EU
    #12 Matteo, Jul 27, 2015
    Last edited: Jul 27, 2015
    I guess you mean the new cells are unknown. For the 85 cells there is a lot of data in Merijn's battery survey. USA visitors can also enter their data and you can submit multiple entries over time which is a good idea.

    [​IMG]
    Like I said, I would expect one of these scenarios based on Elon's statements and blog post:
    A) 95 kWh in 2016 and 100 kWh in 2017
    B) 100 kWh in 2017

    They might do a design refresh. A few times Elon said a design refresh should be expected in 4 years and a bigger design change in 8 years. That means (hopefully) they might get rid of the plastic nose cone. Other surprises could be additional autopilot hardware. The MS doesn't have a rear radar. Therefore it can not do lane changes. Tesla has been advertising automatic lane changes even though the car can not do it automatically (the driver needs to check mirrors and make sure there is not a speeding car coming from behind). I think after autopilot lane change is released they will find out that misleading advertisement causes accidents. It is misleading because the MS page here says "Lane Changing: Automatically change lanes by tapping the turn signal". I expect accidents, bad media coverage and hardware changes (rear radar) after autopilot release. Btw, I'm not just assuming people will misunderstand autopilot lane change. I know they misunderstand it because I have seen 3 videos where the reviewer described incorrectly how this will work. Therefore the car not having a rear radar, combined with Tesla's misleading advertisement to me says hardware change within a few months after lane change feature is released.
     
  13. smartypnz

    smartypnz Member

    Joined:
    Jan 23, 2013
    Messages:
    572
    Location:
    Monterey Peninsula
    I don't think the 85 will go away...
    It'll become the new low standard when the 110 comes out.
     
  14. Matteo

    Matteo Member

    Joined:
    Jul 6, 2015
    Messages:
    168
    Location:
    EU
    Even the 60 kWh and 85 kWh batteries have the same curve, meaning that they both supercharge to same percentage at the same time. Before you object and tell me about Bjorn's comparison video, let me add that his video is one of the videos I used for data. Accumulated rated range is very different but percentages are the same. Therefore it is fair to assume the 90 kWh will also have the same curve. The curve data the calculator uses comes from data extracted from multiple supercharging videos of 60 and 85 packs. On the spreadsheet this data extraction process is explained on page "STC Process". On that page you can also find links to each of these videos.

    To clarify, the moment the car is connected to the supercharger it selects from 3 pre defined curves based on outside and battery temperatures. Those three pre defined curves are the same for 60 and 85 batteries. The calculator uses the middle curve. Also it uses an average time for rebalancing near the end. When I compared the curves, I found out they were almost the same except the very last percentage.

    The time differences between 85 and 90 kWh happen because to achieve the same rated miles you need to charge to different percentages. For example 240 mi rated range is 240/270= 88.89% of S85D range but it is 240/286= 83.92% of S90D range. Therefore supercharging S85D takes longer.
     
  15. Saghost

    Saghost Active Member

    Joined:
    Oct 9, 2013
    Messages:
    3,026
    Location:
    Delaware
    Interesting. That's the first I've read of this. I guess the 70D would be a good test case - the same voltage as a 60, but with more Ah of capacity, and I believe there are videos for it now. Does it follow the same percentage curves?
     
  16. Arbitrage

    Arbitrage Member

    Joined:
    Jun 1, 2015
    Messages:
    24
    Location:
    California
    Teo,

    I don't think Saghost is talking about that. The 90s have a different battery chemistry than the 60s and the 85s, which have the same chemistry. In theory, there could be higher/lower max amps/voltages that they're able to feed into the battery with a different taper curve due to the different chemistry. For all we know, they might need to charge more slowly because the newer silicon chemistry is less stable when newly introduced or any number of factors. Seeing as how there are 0 of them up on Youtube, then it's tough to have hard numbers until we get a full video up of one charging.

    Once we get real confirmation, then yes any calculators would then be more realistic. Even Tesla themselves was waffling between 5-7% increase over the 85 depending on which document or source from Tesla was examined so we don't even know the rated range yet.
     
  17. Electricfan

    Electricfan Member

    Joined:
    Aug 24, 2013
    Messages:
    971
    Location:
    Houston
    my two cents: don't be the first duck in the 90 kwh pond. There is a ton of evidence the old battery will last and provide good service for many years. I was a little unnerved by EM's lack of emphasis on the new battery chemistry in the 90 announcement - you've probably seen the thread on this forum, if not I can provide a link if you don't see it in a quick search. But for a very tiny increase in capacity you're taking a risk. How big a risk? Nobody knows. Why do it?

    Before I bought it I'd have to hear a whole lot more from Tesla about how they've tested the longevity of the new chemistry.

    But... this is a classic case of testing your personality type - risk taker vs risk averse. If you get the 90 and it turns out it lasts 100% longer than the old chemistry, you could win big!

    Let us know what you choose!
     
  18. Matteo

    Matteo Member

    Joined:
    Jul 6, 2015
    Messages:
    168
    Location:
    EU
    #18 Matteo, Jul 27, 2015
    Last edited: Jul 27, 2015
    Saghost,
    At the time I couldn't find any 70D supercharge videos. I will check again and see. If there are we can certainly add it to the same chart. The first chart on STC Process page already shows 2 S60 and 4 S85 curves on the same chart.

    Update: I searched for 70D supercharging videos and can't find any. If you or somebody else knows a 70 kWh supercharge video that is from almost empty to full and you would like to see the curve side by side with 60 and 85 curves, let me know and I will add it. You can send me the video link with pm here or open the supercharge time calculator here, find the page "Feedback" and write there. In case some readers have lost track of the discussion, let me summarize: the numbers the calculator shows now are very good. We can add more information about the details over time.


    Arbitrage,
    I think the 90 kWh pack has the same number of cells and modules as the 85 kWh. It can't have less pack voltage because that would impact performance negatively. It can't have less cell voltage either because that would require a complete redesign of modules and number of cells that go into each module etc. It would be a very complicated job.
     
  19. plaid

    plaid Member

    Joined:
    Jul 18, 2015
    Messages:
    6
    Location:
    New Jersey


    This sums up my thoughts.

    Am I a risk taker? Buying a tesla is taking a risk (I haven't quite gotten there to pull the trigger yet), although I feel like buying the biggest battery offered is the right decision.


    /
     

Share This Page