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How far have you gone on 0%?

Discussion in 'Model S' started by maggo321, Sep 2, 2017.

  1. maggo321

    maggo321 Member

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    Not that I ever plan to get to 0%, but was just interested if anyone has got this low and had to keep on driving?

    I think I've read on another forum 17 miles before he charged (implying it had further left)!

    I start sweating if my previous ICE cars have gone into the red, so will probably never go below 25% charge in my MS.
     
  2. DrivingRockies

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    I used to say the same thing. Road trips - you'll get comfortable watching the range estimate. :cool:
     
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  3. sakimano

    sakimano Member

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    Exactly. After a while get comfortable, then adventurous, then aggressive. I imagine stupid is next for me.

    I've been down to 4 kms of range before. Don't use % though on the indicator.
     
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  4. kort677

    kort677 Active Member

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    There are many threads that go into this topic, doing a search will get you many views on this. The best advise would be try not to get that low of a soc. The wait for a tow can be very long
    That said trying to never get below 25% is not necessary for anyone to adhere to
     
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  5. ChadS

    ChadS Petroleum is for sissies

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    THERE IS NO DRIVING RESERVE.

    It makes no sense for Tesla to have a driving reserve. It doesn't help drivers (in fact it makes range calculations more complicated), it would encourage people to drive until empty which is where all the drama is, and it reduces their range claims for marketing - they want to use the largest number they can.

    Telsa has repeatedly said that there is no driving reserve.

    These forums have many examples of people running out at zero, and in fact a few unlucky ones have run out just before 0 (more likely if you are, say, driving fast uphill).

    So there is clearly no driving reserve.

    SO WHY DO SO MANY PEOPLE THINK THERE IS A DRIVING RESERVE?

    Because the battery does not store miles. It stores energy, and gets shut off at a certain voltage. It is very difficult to estimate exactly how many miles it will be until the battery shuts down, especially since it depends on many variables (many environmental or under control of the driver, rather than the car) that both vary and are difficult to measure. So some people will make it past 0. But it is not because there is a driving reserve; it is because they are lucky. You cannot count on going past zero. Plenty of people have not been able to do so.

    Somebody even made a diagram of how the battery is used that includes a driving reserve. But that diagram did not come from Tesla, and it is not correct.

    Not to mention that there is an anti-bricking buffer in the battery. You can't use it for driving - the car shuts off before you use it - but some people get confused by the word "buffer".

    SO WHAT SHOULD I DO?

    Charge your car BEFORE you get to zero.
     
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  6. Haxster

    Haxster Member

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    48 miles

    … on a flatbed :eek:

    (not really)
     
  7. wallstguy

    wallstguy Member

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    Pretty much got to a supercharger exactly when my car hit 0km. That's as far as I've gone haha. Could've conserved some battery but I knew I was going to make it so continued to drive the way I normally do
     
  8. GSP

    GSP Member

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    Check out Bjørn Nyland's video where his X shut down several miles before reaching zero. No EV has a perfect mileage estimator. As explained up thread, the battery will shut down when it reaches a minimum voltage (on any one cell) to protect itself. How close it is to that point cannot be estimated to the exact mile.

    Plug in before you get low.

    GSP
     
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  9. tcbailey239

    tcbailey239 Member

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    I had a drive a few weeks ago that ended at my house with an estimated 0% / 1.5 miles left. I parked in my driveway and went inside for a bit before coming back to pull the car into the garage. When starting, the main screen wouldn't display anything other than the grey back ground and Tesla "T". I assume this was the car's hint to not drive any further. Luckily I don't live too far from a super charger so a few hours charge and I had enough to make it to super charger. So related to this post topic...technically I didn't drive anything past 0%. I was too scared and my wife would never let me forget it if I needed a tow.
     
  10. yobigd20

    yobigd20 Well-Known Member

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    0. it shuts down on or before reaching 0 miles range.
     
  11. mcbarnet007

    mcbarnet007 Member

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    lithium ion battery really hates to be fully depleted, if your battery pack is unbalanced it could really damage some cell. Just don't go to 0!
     
  12. TIppy

    TIppy Active Member

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    #12 TIppy, Sep 5, 2017
    Last edited: Sep 5, 2017
    Tesla won't let you deplete the battery to damaging levels. They shut the car down before that happens. I recently tested my p90dl for below zero range, and monitored the battery as I did so. When I got to zero miles, the battery indicated it had 4kwh of capacity remaining.
    The voltage at that point was 302.9 volts, or about 3.155 volts per cell. I continued driving for another 12.8 miles at 25 mph around my neighborhood. The battery then reported 1.3 kwh remaining, and the voltage was 291.4, or 3.035 volts per cell.

    In a blog post about the roadster battery, Tesla says they shut the car down when the cell voltage drops below 3.0 volts, or 288 volts for the pack. I don't know if this is still true for the model s. One of my bricks was at 2.998 volts, and the car did not shut down. It may be that the pack voltage has to drop below 288 volts, or an average over all the bricks of 3.0 volts.

    In a video about his model x shutting down, Bjorn Nyland interviewed a guy who checked the can bus data as he ran his car to shutdown. He said that the car shut down when one of the bricks reach 2.5 volts which is the normal cutoff for lithium ion cells. This may be an additional precaution in addition to the 288 volts for the pack.

    It appears that Tesla runs the pack down to 288 volts when it does its range test for epa data, so the epa range includes below zero miles range. That they run the battery down to 288 volts implies that they still use the 3.0 volt per cell cutoff. That would leave the remaining capacity down to 2.5 volts for anti-bricking.

    Panasonic says you can bring the voltage down to 2.0 volts as long as you recharge at a much reduce rate until you get to 3.0 volts.
     
  13. tfung

    tfung Member

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    How much longer can you use your cellphone when the battery reaches 0? :)

    I'm guessing the batteries would still have juice left in them when it shows 0, but maybe just to keep essential systems running....
     
  14. TIppy

    TIppy Active Member

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    But you don't have to guess, because the car tells you what's left after the instrument cluster reports zero miles.
     

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