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Battery discharges at a rate of 1% per day (page 25 Model S owners manual)

Discussion in 'Model S: Battery & Charging' started by montgom626, Dec 27, 2012.

  1. montgom626

    montgom626 Active Member

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    Even when you’re not driving Model S, the Battery discharges very slowly to power the onboard electronics. On average, the Battery discharges at a rate of 1% per day. Situations can arise in which you must leave Model S unplugged for an extended period of time (for example, at an airport when travelling). In these situations, keep the 1% in mind to ensure that you leave the Battery with a sufficient charge level. For example, over a twoweek period (14 days), the Battery discharges by approximately 14%. Discharging the Battery to 0% may permanently damage the Battery. To protect against a complete discharge, Model S enters a low-power consumption mode when the charge level drops to 5%. In this mode, the Battery stops supporting the onboard electronics to slow the discharge rate to approximately 4% per month. Once this low-power consumption mode is active, it’s important to plug in Model S within two months to avoid Battery damage. NOTE: When the low-power consumption mode is active, the auxiliary 12V battery is no longer being charged and can completely discharge within 12 hours. In the unlikely event this occurs, you may need to “jump start” or replace the 12V battery before you can charge. In this situation, contact
     
  2. Zas

    Zas Sig. Performance #2113

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    its worse in the winter.. mine was left fully charged at night with 435 km, and in the morning it was 425 km - thats 2.3 %
     
  3. TonyWilliams

    TonyWilliams Active Member

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    #3 TonyWilliams, Dec 27, 2012
    Last edited: Dec 27, 2012
    The battery is being heated virtually all the time in cold weather. For truly long term storage, it may be wise to disable the battery heating and cooling. I don't recommend leaving the car in a hot place for storage, but cold is certainly ok, provided the batteries aren't allowed to freeze at -30C.

    I also recommend those cheap solar 12 volt trickle chargers, provided the car is in the sun.
     
  4. Zextraterrestrial

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    that is only from a full SOC. The rate of discharge will slow considerably at a lower SOC
     
  5. mknox

    mknox Well-Known Member

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    I have a 12v solar trickle charger that I use on a battery box I keep in my work room. It came with a cigarette lighter adapter, and I assume that it what you're talking about. Question is, does the 12v port in the console stay "on" when the car is off? (It would have to for this to work). One of my current cars keeps the 12v socket on while my other car shuts it off when the car is off.
     
  6. Francis Lau

    Francis Lau P-1456

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    Is the 1% number based on 300 miles for the 85kWh? And if you have the 40 kWh, it is still 1%? IMHO, Using percentage seems strange.

    In the past 2 nights, I took notes of the rated mileage at night and in the morning, it went down by 4 "rated range" miles each night. The evenings were cold i.e. lower to upper 30's and I was parked outside. I am running 4.1 and was in sleep mode and the car wakes up fast enough in the morning.

    4 miles is about 6.5 km so @Zas's 10 KM number lines up; since Toronto is colder in the low 20's.
     
  7. wiztecy

    wiztecy Active Member

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    #7 wiztecy, Dec 27, 2012
    Last edited: Dec 27, 2012
    For the Roadsters, when doing 100% full Range Mode charges and you remove the charger the cooling pump and car stays "awake" for a good amount of time to bleed off the high SOC to friendlier SOC. Lithium Ion batteries don't like being at 100% and they don't like being driven down below 20%. They like to be at 50%. But Tesla also has found them to be happy up to 85%, right where the Standard Mode charges in the Roadsters end at. I did a full 100% range mode charge in my roadster and allowed it to sit for 3 days. After 3 days it bled the miles down from 232 miles down to 191 miles. Then after that 3rd day the charge barely dropped since the 191 is around the 82-85% SOC.

    I don't know anything about the S such as if they bleed the battery down or what, I'm guessing they do. And if they do as Zextraterrestrial
    pointed out, it will be more than 1% until you reach the friendly SOC Tesla has defined for the pack.

    And when comparing different size packs (using the 85% as the target SOC, you'll need to verify it for the Model S), so as an example for the 300 mile pack 85% SOC would be 255 miles. For the 230 mile pack, 85% SOC would be 195. For the 160 mile pack, 85% SOC would be 136.
     
  8. montgom626

    montgom626 Active Member

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    Would disabling it put the battery at risk?
     
  9. jerry33

    jerry33 S85 - VIN:P05130 - 3/2/13

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    It shouldn't. Batteries can take the cold if they aren't doing anything. When you get back you'll want to plug it in and turn the heating back on for a bit before driving.
     
  10. Zas

    Zas Sig. Performance #2113

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    I mentioned this to Tesla service, they said to keep the charger plugged in all night, and that would also keep the battery warm - however , i tried this yesterday night, and with the NEMA charger it didnt work.. i still lost 8km overnight from a full charge - even though the charger was plugged into the car.. so it must 'auto-shut off' and not top off when needed ..

    i am going to try Doug's idea of charging with a standard plug ( 110 V ) - that will be a slow but continual charge overnight and into the next morning to see if that makes a big difference.
     
  11. Robert.Boston

    Robert.Boston Model S VIN P01536

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    One can also simply dial down the amps on your 240v connector, if that's easier.
     
  12. mcornwell

    mcornwell Active Member

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    Do we know what the temperature is that the car will start to warm the batteries while sitting?
     
  13. pbrulott

    pbrulott Member

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    Guys, this is a temporary fix isn't it. We should expect plugging the car on 110V to heat the pack and keep the electronic alive without loosing charge. Please say yes
     
  14. Brian H

    Brian H Banned

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    Should be able to get the same effect by dialing back the amperage to 10 or less on a 240 feed.
     
  15. dtich

    dtich #P708

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    guys, don't forget, as recent posts have pointed out.... the battery purposefully bleeds charge to maintain the most friendly SOC level... what you're seeing may not be solely the result of temperature drops. the battery will not continuously 'top-off'.. it has thresholds to meet before it will start to charge again, for the good and long life of the battery.

    the way to manage this is (when they enable it, i know, i know..) to set a start charge time that takes into account your vehicle ready-to-drive requirements. then you will be able to have maximum battery-safe charge when you drive away with a warm battery.

    simply plugging in all night will not keep it fully charged continuously... nor would you want it to.

    my 2¢.
     
  16. mknox

    mknox Well-Known Member

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    I think I would prefer a charge timer before the smartphone app. I would like to be able to program the car "to be ready at 7:30 am" or something like that rather than have to remember to use the smartphone app some number of hours ahead of when I want to leave. I am anxious for the phone app for other reasons, but to address this loss of range when we go out to drive our cars, a timer like this would be very useful (not to mention enabling us to utilize TOU electricity rates).
     
  17. Zas

    Zas Sig. Performance #2113

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    thats a good idea mknox, you could then plug your car in, and tell it to start charging at 5am through the screen UI, knowing your charge will take approx 3 hours..perfect timing for when you leave for work.
     
  18. ebbrey

    ebbrey Member

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    If you would be able to select: "car ready for 7 am" it needs to check the charge rate from the plug first so we dont have to do that incase we are in different locations and want to rely on the "timer"
     
  19. mknox

    mknox Well-Known Member

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    Sure. I'm thinking I get home, plug in and tell the car I'm leaving at 7 am the next morning. The car then looks at the state of charge, what it's plugged into and determines when to start the charge cycle. I'd also like to be able to program in TOU rate periods so that the car can also base its calculations on keeping out of high rate periods if possible.
     
  20. montgom626

    montgom626 Active Member

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    From what I have read on this forum, those features should arrive. I always hate to mention this, but these features are already part of every Chevy Volt. So if Chevy can do it, TESLA can do it. Just a matter of waiting for an update.
     

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