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The only Battery Answer you will ever need! [Personal Opinion]

Discussion in 'Model S: Battery & Charging' started by CertLive, Dec 15, 2019.

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Did this help your battery karma?

  1. Yes

    30.0%
  2. No

    70.0%
  1. CertLive

    CertLive Member

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    So many understandable questions about battery usage.

    The answer: Your battery is monitored by a BMS ( Battery Management System ) this gives you a majority slice of the pie which is not down to 0% nor is it up to 100% of your battery. So the answer with the latest generation of cells and the model 3;s improved design are... Charge the car as fast or as slow as you damn well like as the system will dictate and manage it whatever the road conditions and temperatures are. Set it to that little notch on your app at 90% and keep it topped up just in case or whenever. Why would you close your potential capacity? or fill it right up to limit its regenerative breaking? Its all designed there silky smooth so no worries!

    No need to even worry about it at all just charge your car as you like at whatever speed you like in harmony with the places you want to drive to, the software and its improvements over time will take care of the battery.
     
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  2. spaceballs

    spaceballs Member

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    If it were only so simple! Advanced users might want to extend battery cycle life by keeping it at a lower SOC over time.
     
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  3. CertLive

    CertLive Member

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    But that is a lower SOC for the large slice of the pie you have not the whole battery capacity. In real world driving is that really going to have an effect noticeable above the expected 1% per year range loss when you average it out?
     
  4. spaceballs

    spaceballs Member

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    Yes in my view, note I have tested model 3/S, Roadster etc.. cells and have built BMS systems.
     
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  5. jordanair45

    jordanair45 2019 Model 3 SR+ w/ FSD

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    A thread with good intention.

    I’m going to sit back and see this thread ballon to 100 pages lol
     
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  6. boaterva

    boaterva Supporting Member

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    Elon has said 90 is fine. I think that’s good enough for me. :D We charge the commuter 3 to 90 and the less-frequently used X (the older batteries, also) to 80. Seems like a good compromise to this engineer.
     
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  7. RCFLMA

    RCFLMA Supporting Member

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    Makes sense to me. We all get to choose what we want to worry about in life.

    It's analogous to range anxiety, where you can worry all you want at whatever price you want to pay in terms of your mental stress, endorphins, blood pressure, karma, peace of mind, chi, happiness, etc. Pick your battles and your worries.

    Also reminds me of the DOS days where everyone neurosed about freeing up as much of the 384k RAM (between 640-1024k).

    Chill out and enjoy the car. It's a trip by itself.
     
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  8. CertLive

    CertLive Member

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    A config.sys and autoexec.bat away from the fun of a new game being denied to you by a cdrom driver ahhh boy do we have it easy now!

    What I am trying to communicate is Tesla have this in hand if you have an older car or new. Charge it how you want and it adapts without damage being done. A full battery to you is not quite as full to the BMS so why not keep it nice and topped up at whatever speed you like :D or it lets you tbh.
     
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  9. TMThree

    TMThree Active Member

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    Even that isn't enough, major factors include SoC, temperature, and age.

    You can't do anything about age, but you sure as hell can deal with SoC. Temp is not as easy, when you need to recharge, you need to recharge, especially on a road trip, but at home you can schedule charge so its done when your garage is cool and the car has cooled down after driving. That also helps with SoC since you can limit the time your cells are kept at an elevated SoC.

    The people who run around saying they charge to 90% daily when they don't need to charge that high, are all going to be complaining about their decreased range in a few years. It won't be significant (ie.; your car is still usable) but it most definitely will be measurable.
     
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  10. TMThree

    TMThree Active Member

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    He previously recommended 80%, and agreed with a battery researcher that 70% is better still.

    The curve is parabolic, so 100% is really bad, 90% is less so, but that doesn't make it a fantastic number to pick.

    For a car company, across its fleet, it's easier to say charge to 90% than describe the nuances of battery pack lifespan, design, and upkeep. Especially if they start getting *sugar* for telling customers they can't "fill up the tank"

    As long as the battery capacity remains over 70% within the 8 year warranty, that's really the major hurdle for them, and 90% daily should work fine for that. But as a consumer who wants to maximize lifespan (and thus usable range), charging to 90% if you don't discharge down to 10% is a waste and harmful to the overall lifespan of your battery.
     
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  11. TMThree

    TMThree Active Member

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    If you only use 20% of your battery daily driving to work, then you should charge to 60% and drop it down to 40%. That keeps the cells neutral, and limits the depth of discharge. The further you stray from neutral (50%) the more stressful it is. The deeper the discharge, the more stressful it is. I mention this because my coworker enjoyed charging his car every 3 days, and I told him while this isn't really a big deal, he'd retain more of his battery over its lifespan by charging nightly to limit DoD.

    No one should be saying: Don't use your car! But you can pick smart limits for your battery SoC to fit with how you do use it. So for example, if you have a long commute and use up 70% of your battery, then your charge limit should be 85% and drop down to 15%. And better yet, set your charger to complete charging just before you leave, so your car isn't idling with an elevated SoC all night needlessly. This has zero impact on your usability of the vehicle but helps the lifespan.

    As far as range loss, you should expect more loss the first 2-3 years, it's not linear. And loss will not be the same for everyone.

    There are some really good charts and details about lithium batteries on this site:

    https://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries
     
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  12. CertLive

    CertLive Member

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    I do not believe this statement is true because when you as a user charge the battery to 90% it is not 90% of the total battery capacity and therefore just fine. The BMS is in complete control of it through its lifespan which is into the 100k,s of miles and adapts with the wear and conditions. So the whole battery debate is really not any worry to the consumer as it is not with a mobile phone until it dies. Which at this point in EV maturity is what 300K plus miles?

    You never have 100% of your battery only 100% of your slice, this BMS manages the stress levels without worry to the user.
     
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  13. TMThree

    TMThree Active Member

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    Tesla has a buffer, but its small. It's not like other car companies who lock away 30% that the consumer can never use. If 30% was locked away, then absolutely, going to "100%" would be fine. The stress levels at 70% is only marginally more than neutral (see chart below)

    Just because you can't hit 100% and 0% doesn't mean 100% isn't stressful, or that 90% isn't stressful.

    This chart is from another thread on this forum and shows succinctly the parabolic curve SoC has. If we assume for a moment that 100% readout is actually 95% absolute SoC, that still means the cells are still stressed significantly more than at neutral.

    I charge to 65% just before I leave for work, and when I arrive I'm at 55%, thats close to neutral, and about as good as it gets in terms of stress under heat.

    [​IMG]
     
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  14. spaceballs

    spaceballs Member

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    #14 spaceballs, Dec 15, 2019
    Last edited: Dec 15, 2019
    Wow lots of misinformation here... others will correct you. The BMS will handle a lot, but simply put the End user can control cycle count, SOC, and pack temp (somewhat i.e. garaged or not) that directly affects SOH of the battery.
     
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  15. boaterva

    boaterva Supporting Member

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    His most recent recommendation is/was 90, and it's probably more applicable to the newer batteries.

    As I said, we use 90 for the car that's used daily (probably 60-70 when it gets home). The one with the original battery chemistry isn't used as much, so we keep it lower around 80% on purpose).
     
  16. CertLive

    CertLive Member

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    My point of view is the other companies use flat packed and different chemistry batteries which require them to save large amounts of capacity behind to fight sooner oncoming degradation possibly? Is the chemistry and design of the Tesla cells not proven already to do a tremendous amount of miles in a cars potential life span? So regardless of SOC the BMS will give you a reasonable time of 8+ years of 1% average loss per year. This would show the battery pack to be able to deal with charge how you like situations all the way up to that 90% controlled by the BMS. Seems to me again you do not need to worry at all about how you charge your battery the BMS is doing all the work and worrying for you. The SOC should not be a concern for your car at all unless you leave it there for months flat and even if this extreme case happens the BMS will slowly bring it back to life.

    There really is 0 to fear here in 2019, you are going to get a good life and miles out of your battery for many years with a Tesla no matter how you like to charge it. So plug it in whenever and have no fear of charging it right up to the notch on the app every single time at 7kw or at 175kw its all designed in.
     
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  17. spaceballs

    spaceballs Member

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    You have no real data to back up your illogical conclusions, your simply trolling now.
     
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  18. TMThree

    TMThree Active Member

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    haha. Yeah, it's not like anyone is scared (as he claimed). It's just about maximizing your battery lifespan. If he wants to charge to 90% SoC daily, go for it. I just don't want to hear the whining in a few years when he finds out his car has 5% less range than those who charged to lower SoC.
     
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  19. CertLive

    CertLive Member

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    So ask the guy who reached 100,000 miles and excessively supercharged and got 2.5% loss. "Musk said that they built Model 3 to last as long as a commercial truck, a million miles, and the battery modules should last between 300,000 miles and 500,000 miles."

    If you even average that out for 95% of people who buy one why exactly are you even the slightest bit worried on the soc or what speed you charge it? Graphs show one thing, real world usage in the hands of the consumer show another and yes I am focusing on the Model 3 as an owner and as it uses the most advanced system that is at this worry free point.

    Again proves there is no need to worry just go by the markers on the app for daily and travel @ 90% or 100% respectively as you never do charge it 100% to damage it. The cars software will not allow it.
     
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  20. spaceballs

    spaceballs Member

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    Again spouting stuffs without facts to back them.. you just join today and started this thread and is spreading false info...
     
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