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How many range charges are too many?

Discussion in 'Model S: Battery & Charging' started by artsci, Aug 25, 2013.

  1. artsci

    artsci Sponsor

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    I've been doing range charges on average about once a month. Is that too many or should I not be concerned? The rest of the time my charges are of the daily variety, usually up to about 120 miles of range.
     
  2. jerry33

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

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    Elon said that doing a range charge every day won't void the battery warranty. However the actual answer to your question is, "We just don't know". My opinion is that one out of every thirty charges isn't going to make that big a dent in battery capacity--at least with the 85 kWh battery. Also there are range charges and range charges. That is: Should a range charge be considered any charge that goes past the daily charge high mark, or is is only if you charge to top?
     
  3. Plug Me In

    Plug Me In Member

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    My understanding, but only from reading these and Tesla Motors forums is that the real risk of range charging is topping up the battery and leaving it to sit fully charged. I've range charged probably about a 10-12 times but usually time it to finish right when I'm ready to hit the road.

    How was Emerald Isle? I charged at the Holiday Travl Park there last spring.
     
  4. SCW-Greg

    SCW-Greg Active Member

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    The bigger issue with range charging, is how long (after topping off) does it sit before you drive/discharge? The less time is sits at the high end of SOC, the better. I would think it wouldn't be that hard on it, if you can start driving right away.
    But like Jerry says, we don't know. But in the coming year(s) we will have enough of a base to know.

    Interesting in that Model S will soon be providing the world invaluable (definitive) data for real LI longevity and care... thinking phones, laptops, etc. Even if the chemistry in the Model S is tweaked a bit differently from std commercial batts.

    Edit: Looks like Plug Me In and I were writing at the same time, with similar thoughts. ;)
     
  5. Cottonwood

    Cottonwood Roadster#433, Model S#S37

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    Plug Me In and SCW-Greg are correct, and the real double whammy on the battery is to leave it at a high SOC at high temperatures.

    Its easy to minimize your time at the "Range," 100% SOC. The procedure that I follow is to charge to normal, 90% SOC the afternoon or evening before a trip, then when that is done, I set the start charge at 1.5 hours before I expect to leave, and set the charge limit to the max. It only takes a little over an hour to go from 90% to 100%, but leaving 1.5 hours gives me some margin. You are not going to do very little harm with an hour or two at 100%.

    Enjoy!
     
  6. artsci

    artsci Sponsor

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    I'm there now and charging at Holiday Travel Park. And thanks all for the tip -- I was not aware that the longevity of a full state of charge was the issue to be concerned about.
     
  7. Puyallup Bill

    Puyallup Bill Member

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    #7 Puyallup Bill, Aug 25, 2013
    Last edited: Aug 25, 2013
    The following is an extract from a Tesla engineer's(?) comments concerning Roadster battery degradation:

    Think of battery degradation this way. It is very much a function of time spent at voltage and temperature. For instance, you do not want to charge a car all the way in performance mode, and then let it sit in the sun all day. Between the higher thermal limits and the high SOC, you are causing the battery a relatively high amount of degradation .In fact, the car will eventually allow itself to discharge to Standard levels if left in Performance mode to prevent inadvertent damage to the battery. If you start driving right away after charging in Performance or Range Mode, and don’t let it sit, you would minimize the damage incurred, as the time spent at these extremes is an important part of the calculation.

    The full text of the three year old post is here: Tesla Roadster Battery Care

    Added: Li Laptop batteries seem to have a relatively short life - at least earlier ones. A battery "expert" I once read suggested that to prolong Li laptop battery life, if the laptop is used like a desktop and always plugged in, remove the battery to prevent it from being held at a constant high state of charge. Perhaps newer battery management systems take care of this, but my battery stays out except when traveling.
     
  8. Vger

    Vger Active Member

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    As far as I know, the same logic and advice applies to the bottom 10% of SOC. It is not necessarily terrible to run your battery to a very low SOC, if you can and do recharge it out of that region promptly and quickly, and avoid high temperatures.
     
  9. Cosmacelf

    Cosmacelf Active Member

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    And again, don't freak out about running your battery all the way to 0 rated miles since the car has a hidden buffer of about 10 - 17 miles below zero before the car shuts down. And even when the car shuts down, it isn't at zero since there is a reserve even there to prevent permanent damage to the battery. Just don't leave your car sitting near 0 miles charge for longer than you have to.
     

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