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Battery Discharge Procedure?

Discussion in 'Model S' started by m2140, Jan 23, 2017.

  1. m2140

    m2140 Member

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    Does anyone know of a way to Discharge the battery on a model S without having to put miles on the car?


    I'm having a problem with charging. My Model S 85D wont charge to 100% anyone. Sometimes it completes charging at 96%, sometimes at 98% others at 99%. Charging for the top 10% of the battery is also extremely slow. Much slower than normal. 30min to an hour extra.

    I've taken the car in for service and after a week they recalibrated the chargers and was asked me to perform 3 charge cycles from a low charge state and back to 90%. The service center said they don't have any process to discharge the battery. My only option is to drive the car or turn on components and wait. If they did it, it would take along time. So they asked me to perform the discharge cycles.

    I just completed all 3 cycles and I still have the issue. In fact it's worse now.

    There has to be a way to discharge the battery without putting miles on the car or adding to the wear & tear of the car.
    To run the cycle in need to run the car 180-200 miles for each cycle.
     
  2. BestRadar

    BestRadar Member

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    Maybe leave the heat on high and leave the windows open. That would surely burn some energy without moving.
     
    • Informative x 1
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  3. Andyw2100

    Andyw2100 Supporting Member

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    I'm pretty sure this or something like this is what the service centers were doing to run down the packs when they were doing Ludicrous upgrades.
     
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  4. HankLloydRight

    HankLloydRight Fluxing

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    Once I was doing a range charge to leave on a trip, but got delayed a day... so I went down and cranked the heat, seat heaters, lights, everything I could.. and it did drain down the battery a bit, but not as much as I'd like. I think I got it down to 94-95% and then went for a short drive, I think, to get it down to 90% for overnight.

    So you can do it, but it's slow.
     
  5. MarcusMaximus

    MarcusMaximus Member

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    Couldn't you simply wait longer before trying to charge it? As in don't plug it in at night until you get down fairly low? That wouldn't put any extra miles on your car beyond your normal driving.
     
  6. m2140

    m2140 Member

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    This is basically what the service center was going to do. 3 charge cycles would have taken weeks. So they asked me to drive the car, and I did to the tune of 600 miles on the car. I'm trying to avoid putting too many extra miles on the car. I already drive it a lot, but mainly on the weekends (i work form home).

    I'm just surprised Tesla does not have a procedure or even the equipment at the service centers to discharge the battery. i though they could just as easy put the power back into the grid or something.

    If there is no process, what do body shops do if a Tesla is in an accident? a fully charged battery pack could be dangerous to handle. How are those battery packs discharged when the car is not functional?
     
  7. James Anders

    James Anders Member

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    Drive in reverse?
     
    • Funny x 2
  8. apacheguy

    apacheguy S Sig #255

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    Tesla service can drop the pack and attach a 15 kw resistive heater. I don't know of any way for an owner to accomplish this on their own.

    Did they say why the car was not able to attain 100%?
     
  9. HankLloydRight

    HankLloydRight Fluxing

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    Thanks Ferris. :/
     
  10. m2140

    m2140 Member

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    No they still cannot explain it. Charging at the top is also extremely slow. I have been documenting the hell out of the charge times so they can pull logs and they tell me there are no errors and i'm getting a full charge. But they have no explanation for the slow charging or the guage reading anywhere between 96-99% charge at completion.

    The biggest problem for me is the slow charging at the top end. I take a lot of long trips in my S. I need the little bit of extra charge at superchargers with some of the location we go to. I cant wait 2 hrs at a supercharger because the car is having charging issues so I have been driving my gas car more these days.
     
  11. apacheguy

    apacheguy S Sig #255

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    @m2140 it would be interesting to see some CAN logs of the brick voltages at max charge.
     
  12. m2140

    m2140 Member

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    Can I request those and will Tesla give me a copy?
     
  13. apacheguy

    apacheguy S Sig #255

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    They will not. But you can do it yourself. Look up TM Spy
     
  14. Nietschy

    Nietschy Member

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    Heat to max and door open just a bit to let it run on.

    this takes 5kW per hour from your car. so it will be empty over night. I used 35% by heating in 2 hours, while trying to dry the interieur after a rain storm with open sun roof...

    but the battery will not like it very much... make sure the charge cable is in range and the charge port is open.
    even consider to jump start the 12v as this might be empty too then.
    btw: service ppl do no empty the battery, not ever.
    you might damage it irreversible doing so...
     

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