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Frequent supercharging - harmful?

Discussion in 'Model S: Battery & Charging' started by pbleic, Mar 12, 2014.

  1. pbleic

    pbleic Member

    Feb 4, 2014
    Plug in America's website says that frequent fast DC charging can be bad for a battery. Is this true for supercharging Tesla's batteries?

    This is what they say:

    DC Quick Charger
    An offboard charger that connects directly to a vehicle's high-voltage battery bus. Allows for high power transfer and can charge a battery to 80% or so in minutes instead of hours. Quick charging should be done according to vehicle manufacturers specifications, as this charge method can be damaging to the battery if done too often.
  2. Doug_G

    Doug_G Lead Moderator

    Apr 2, 2010
    Ottawa, Canada
    Tesla says supercharging does not harm the battery. First of all Tesla has active temperature management. Secondly, even during supercharging the cells are well below their maximum C rate. So supercharge to your heart's content.

    I believe this instruction is more relevant to the Nissan Leaf.
  3. ChadS

    ChadS Petroleum is for sissies

    Jul 16, 2009
    #3 ChadS, Mar 12, 2014
    Last edited: Mar 12, 2014
    The answer can be "yes" or "no", depending on how you define "frequent" and "harmful". Tesla doesn't give out detailed information about this, so we have to guess exactly where the lines are.

    The car certainly protects itself - it never charges at over 1.5C, and that's only for a short time then it ramps down, and it keeps the battery cool. So it won't cause "too much" harm. But it does cause some harm, and in fact while Tesla says Supercharging "doesn't harm" the battery, they have also said that Supercharging is not intended to be a sole charging strategy. EVERYTHING you do with your battery, including just driving the car and charging with 110V, harms the battery. Batteries wear out when you use them. The question is, is it an inordinate amount of harm?

    Most honest answer: nobody knows for sure (though there is no shortage of guesses) and it still depends on how you define "inordinate".
    Slightly more helpful guideline: don't Supercharge if you don't have a reason to. But if you want to take a trip, go ahead and use the car and don't worry about it. It will probably theoretically cause more harm than charging on an HPWC, but practically not enough harm that you'd have any way to measure it. Of course, like everybody else, I am necessarily guessing.


    Edit: I'll try to get that piece off the Plug In America web site. That was put up when the Nissan LEAF was new, and the original owner's manual said not to DC charge more than once a day or you'd harm the battery. After more testing, they took that line out. Mitsubishi has i-MiEVs that ALWAYS use DC charging, and say they have noticed no issues.
  4. AmpedRealtor

    AmpedRealtor Active Member

    Jun 30, 2013
    Buckeye, AZ
    This is not true with Model S, but is very much the case with the Nissan Leaf. That car's battery is slowly deteriorated every time you give it a high power DC charge. You almost wonder what Nissan was thinking, but there it is.
  5. Gizmotoy

    Gizmotoy Active Member

    Sep 16, 2013
    Bay Area, CA
    Given they removed that statement, I presume they were thinking about playing it safe with their official statements until they had enough data to change the recommendation.

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