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keep car charging to 90% or 50% at home ? for driving every day

Discussion in 'Model X' started by oliver4ever, Jan 16, 2020.

  1. oliver4ever

    oliver4ever Member

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    keep car charging to 90% or 50% at home ? for driving every day ?

    my car MX 90D 2017
    i drive car to work like am using 60km every day >> and keep car in charging evening !
    it's better to keep it's charging to 50% or 90% ? or other to save battary life ?
    and it's better to charge it on 12 A or 30 A ? better to be slowly or quickly ? at home i have maximum 30A ( mobile charger tesla )
     
  2. ewoodrick

    ewoodrick Active Member

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    You really don't need to worry about battery life. It is going to probably last for many years past your ownership.
    Speed of AC charging is irrelevant.

    If you charge to 50% all the time, your car will show degradation, mostly because the batteries don't get a chance to balance. And computer can't reset max. It's not really degradation.
    If you charge at 90%, there are some who believe that this is not the absolutely most optimal place to be at.

    Just set to whatever best fits your needs and stop worrying about it.
     
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  3. oliver4ever

    oliver4ever Member

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    helllo that mean 50% not ok ? and 90% ?
     
  4. ewoodrick

    ewoodrick Active Member

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    No it means that there are slight advantages of each and disadvantages to each.

    But in general, do what fits you best.

    I'll step out slightly further and say that if you set to 90%, then you'll probably be able to just ignore it.
    If you need to make a trip, feel free to charge to 100% at any time. It won't hurt the battery.
     
  5. DirtyT3sla

    DirtyT3sla Member

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    Just charge to 90% nothing bad will happen.

    What if you charge to 50% but then suddenly need to do some extra driving? Oops, you're stranded.
     
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  6. doghousePVD

    doghousePVD My grandfather’s car

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    My choice is when in RI (mostly local driving) I charge to 80%. In ME I charge to 90% as we are more likely to drive farther and there are no nearby SC. Occasionally to 100% but I've found with a planned trip I very rarely need 100%. Often 80% or lower gets me to the next SC, and even 100% doesn't get me to skp a SC.

    I do not have any science to support 80% vs 90%. My guess is never charging above 50% is sub-optimal, but not terrible. As others said, don't worry about it; you seem to be putting very little stress on your battery.
     
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  7. mba83

    mba83 Member

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    Charge to 80% and don't worry about it.
     
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  8. oliver4ever

    oliver4ever Member

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    And speed charger ? 12A or 30A
     
  9. ewoodrick

    ewoodrick Active Member

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    Irrelevant. It's just the amount of time the you need it charged in. So, to a degree, the faster the better, but as long as it gets charged, it doesn't matter.
     
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  10. Techniques

    Techniques Member

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    Like everyone is stating, you charge based on your driving situation. I have a daily 90kms round trip to work everyday, because I live in a climate, I personally charge to 90% during the winter months, and 80% during the summer. Has worked fine for me.

    I personally wouldn't change to 50% for the fact that if you have a unplanned drive to do, you don't want to risk scrambling for charging.

    And Faster charging is ideal...no need to slow it down unless you have no other choice.
     
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  11. tsh2

    tsh2 Member

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    If you only charge to 50%, you will maybe end up in the 10-20% range some of the time, and this is not ideal. Up to about 60-70% should be no worse than 50 (if you're really comfortable with not needing the range for unplanned trips).
     
  12. ewoodrick

    ewoodrick Active Member

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    From a battery life perspective (and there is significant debate about it, especially as to if it extends overall battery by 100 miles, 1,000 miles, or 100,000 miles) the goal is in the middle. So if you use 20% daily, 60%-40% would be where you want to be. Although again taking it to the absurd, you need to calculate the total amount of time daily that it would be at each range and then average them all out to be 50%.

    In other words, going really low is bad. Very little controversy about it.
    Staying at 100% for long times is bad. But ONLY for long times (like a year).
    But feel free to go low periodically if you need to and to go to 100% if you need to. That's not going to kill the battery.
    Elon recommends 90%.

    Pick whatever other number that you want and no one really knows how the long term life of your battery is going to be, except that it's going to be really long.

    Tesla designs the car so that you don't have to worry about it. So why worry about it. The only thing that can probably be said is that 90% of the expert's advice is going to eventually be wrong.
     
  13. DoctorVenkman

    DoctorVenkman Member

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    There is a very small difference between charging to 80% and 90% on a regular basis. If you're an anal-retentive type who needs to min max everything, charge to 80%, otherwise charge to 90%. The difference comes down to a couple miles of range over the lifetime of the battery. Even if you charge to 100% every time it will only reduce the capacity by 3-5% over the lifetime of the battery. Not a huge deal really.
     
  14. eevee-fan

    eevee-fan Member

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  15. Tam

    Tam Well-Known Member

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    There have been many good rationales on the numbers, so what to choose?

    To simplify it, just plugin as often as you can as instructed by the owner's manual and keep it at 90% as instructed by Service Center:

    Service appointment for 12 month old Model 3 for range loss /invoice for out of warranty inspection?


    [​IMG]




    In the old days before Tesla, without the Battery Monitor System BMS and its liquid cooling system, it's logical to not produce heat to fry your battery so to accomplish that, slower, less current, to produce less heat was desirable.

    But we are not talking about the old days anymore because Tesla has BMS and liquid cooling system, there's no need for slower, less current, to produce less heat because Tesla can optimize the temperature at all times.

    There were concerns about high current so other car companies didn't subscribe to Tesla Supercharging's practice.

    Tesla began with 90 kW Supercharging in 2012. Then, when that worked out fine, it increased that to 120 kW in 2013. And when that has worked fine, it's increased to 250 kW in 2019.

    Other companies now want to do better than Tesla so now they say they can charge much faster than 250 kWh!
     
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  16. DoctorVenkman

    DoctorVenkman Member

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    That graph is terrible because each data series represents a different amount of energy usage in a given cycle (i.e. miles driven). So basically each line represents a different amount of miles driven at any given point on the graph and isn't really comparable to another.

    It would be much better if you converted the x-axis to miles driven instead of charge cycles - the lines would be much closer together. Also, the amount of charge cycles an average vehicle goes through is in the 2000-3000 range, not 5000+, so the difference again is not nearly as much as this graph would like to portray.
     
  17. eevee-fan

    eevee-fan Member

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    The battery chart is not for an EV, it is for Li-ion battery in general and is probably made by someone with en engineering degree, or at least someone in the rechargeabe battery business. It looks correct as is.
     
  18. alphainfinity

    alphainfinity Supporting Member

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    I run mine to 90% in the winter and use 20-30 percent daily. During the warmer months of the year I run it at 80% daily.
     
  19. eevee-fan

    eevee-fan Member

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    Here, found that other thread I read the other day... best to charge 70% - 75% max, unless you are planning to need the additional range. And if you charge to higher SOC, do not keep it in that state too long... drive and draw down the energy soonest.

    Model 3: Charge to 80% or 90%?

    [​IMG]
     
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  20. David99

    David99 Active Member

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    Stay away from the higher end. That's the most damaging. The software update from earlier last year limited many of the older batteries from charging to 100%. They took off the top 10-15%. A clear sign that the batteries do age and degrade faster than expected and that top end is the most sensitive part. I would not charge to 90% if you don't need it. If you daily commute uses 20% battery I'd charge to 70% at the most. I would also use the charge timer so you don't charge right away when you come home, but later at night and finish charging a little before you leave in the morning. That way you keep your average state of charge lower and that makes a difference for sure.

    The BMS need to have the battery levels high and low every once in a while to be able to calculate the range correctly. If you partially charge for an extended time it might get a little confused. That's not the battery going out of balance. It's just the BMS not having good data for a long time and errors add up. So maybe once in a while (like twice a month) charge it to 90% or even higher and discharge it to 10% or lower if you dare. Show the BMS the data from the battery at both extreme ends will help it recalibrate.

    Tesla is using cells that have higher capacity but also last less long than competitors. They also run hotter and need more cooling. It gives them the highest range but they do wear out faster and will fail. We are just seeing the tip of the iceberg right now showing up. It definitely helps to treat your battery well and not just set it to 90% and forget it like so many here suggest.

    The reduction, limiting and backtracking Tesla has done recently particularly to older batteries shows that they are seeing the degradation and feel it's necessary to limit down those old batteries to prevent them from suddenly fail. Tesla has officially admitted that they artificially limiting the old batteries to prevent them from failing. Battery degradation is a real thing, especially with Tesla cells that are pushing the limits more than others. I know this is an unpopular position here. But after owning my Model S for 6 years and putting 260k miles on it I have seen the effects first hand. I'm not fear mongering. Have fun with your car! But when there is a very easy opportunity to help the battery longevity with little to no compromise, do it. It will be worth it in the long run.
     
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