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More frequent shorter charging time or less frequent longer charging time?

Discussion in 'Model S: Battery & Charging' started by Planned_Apathy, Oct 14, 2014.

  1. Planned_Apathy

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    Assume you drive only 30-50 miles per day and that your objective is to minimize battery degradation and otherwise maximize battery life in general. In that case, is it better to charge every day for a short time period to recover each day's 30-50 miles? Or is it better to charge only once every several days when the battery gets near depletion, in which case each charge time would require a longer duration? Or does it not matter?
     
  2. AnOutsider

    AnOutsider S532 # XS27

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    That's a good question, and I don't have the answer... but I do the latter. I charge a couple times per week and just let the car sit (with nightly sleep enabled) otherwise. I think it might be better for the battery to stay at a middling SoC, but unsure if I'm throwing anything out of wack either. Certainly when I do range charges I get some odd numbers (like 254 on max, but range doesn't go down until I've driven for a while), but I don't know if that's the battery or software.
     
  3. dhanson865

    dhanson865 Active Member

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    Best would be depleting to half charge range and charging enough to add the 30-50 miles per day (short charging more often), with occasional charges to full (leaving on charger for 24 hours or so to rebalance occasionally, like once a month or once a quarter)

    Good would be charging to full, discharging to half, charging back to full (longer charges, less often charging). It isn't as good for the battery as riding the middle of the pack but you are driving a Tesla, the difference would be minor.

    Bad would be depleting to 0 miles range remaining and charging to get back the 30-50 miles per day. Driving around on low charge levels would be hard on the battery.

    In short its more important what the average charge level is than it is how often you charge. You want to avoid spending much time at the bottom 20% or top 10% of the pack. Better to be full than empty, better to be mid pack than full.
     
  4. N4HHE

    N4HHE Member

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    More frequent short charge/discharge cycles wear the battery less for the same power consumption than fewer deeper charge/discharge cycles. Tesla's guidance says, "Charge when the opportunity presents." So I charge my 85 kWh to about 210 miles each night.
     
  5. glhs272

    glhs272 Unnamed plug faced villian

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    The best practice is to charge as frequently as possible. This keeps the depth of charge as small as possible. So, charge whenever you can. I have been doing this and my range degradation at 33.5K miles is negligible.
     
  6. yobigd20

    yobigd20 Well-Known Member

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    ^^^^ what these guys said. charge as frequently as possible to minimize the depth of discharges. this will extend the battery life as much as possible.
     
  7. TexasEV

    TexasEV Active Member

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    Doesn't Tesla still put the cards in the car that says "A connected Model S is a happy Model S"?
     
  8. Planned_Apathy

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    Thanks, everyone, for the very helpful responses. And, TexasEV, I've never heard of any such cards and my 9/30/14 delivery didn't have any such card.
     
  9. AnOutsider

    AnOutsider S532 # XS27

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    Nor did my 12/2012
     
  10. dsm363

    dsm363 Roadster + Sig Model S

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    That was more of a Roadster thing. Every single ranger visit would have a card with 'A plugged in Tesla is a happy Tesla' or something like that.
     
  11. TexasEV

    TexasEV Active Member

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    The postcard-size card showing a picture of a Model S plugged in saying "A connected Model S is a happy Model S" was in my Model S when it was delivered in July 2013. Lots of people reported that last summer. I guess they stopped doing it.
     
  12. N4HHE

    N4HHE Member

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    If I were to make a card like that I'd picture a kitten nursing.
     
  13. breser

    breser AutoPilot Nostradamus

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    They had a stack of those cards sitting in the waiting area at the Bellevue, WA Service Center when I was there recently. Didn't have such a card in the car when I picked it up in Seattle.
     
  14. Bighorn

    Bighorn Member

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    I plug in whenever I can and charge to either 80 or 90 percent depending on my schedule. My commute is 40 miles total most days. At 35,000 miles, my range charge is still 311.
     
  15. ZBB

    ZBB Emperor

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    I've gotten one of those cards every time I've taken the car in for service in the last year, including one last week,
     
  16. taurusking

    taurusking Member

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    I just got delivery of my car and I did not get any of those cards from the Dallas Service Center.

    My every day commute equals 85 miles and I did not realize that I have to plug it every day.

    Out of 3 days I have charged only once.

    I did move the bar to 90% charge.

    Thanks guys
     
  17. Cottonwood

    Cottonwood Roadster#433, Model S#S37

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    For a commute like yours, I would set the bar somewhere between 70% and 80% and plug in every day. That way you have plenty of reserve for your daily drive and can forget to plug in for a day with no concern. When you need to go on a longer trip, just raise the bar. Keeping the bar a little lower on a daily basis will most likely give you a little more battery life.

    Enjoy your new Tesla!
     
  18. TexasEV

    TexasEV Active Member

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    It's also in the owners manual in the About the Battery section:

    "Model S has one of the most sophisticated
    battery systems in the world. The most
    important way to preserve the Battery is to
    LEAVE YOUR MODEL S PLUGGED IN
    When you are not using it."

    and

    "There is no advantage to waiting until the
    Battery’s level is low before charging. In fact,
    the Battery performs best when charged
    regularly"

    It reallly is useful for new owners to read the manual. This is not like any other car you have ever driven.
     
  19. taurusking

    taurusking Member

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    I read some where in the forum ( I believe the thread name is degradation of battery or something like that) where the battery needs to be charged at 90%. I do understand the manual says anywhere between 50-90% but lot of users posted that degradation of the battery was minimal at 90% charge.

    - - - Updated - - -

    I did read the manual before I took delivery...some how skipped on this part.. Thanks for reminding me... Will read the manual again... Anything for this amazing car
     
  20. Cottonwood

    Cottonwood Roadster#433, Model S#S37

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    90% as a daily charge is good for reducing battery degradation, but 80% is better. Your daily commute is probably going to use 35-45%. Call that 40% and your daily cycle will be charge to 80% at home, use to 40% during a typical day, repeat. That is a nice gentle cycle on your battery.

    For the battery to be fully calibrated and balanced, you need to do a couple of 100% charges every once in a while, but not doing that does not hurt the battery and probably helps it as long as you don't want squeeze out every mile in a hypermile adventure.

    Enjoy your S!
     

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