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Shut down with supercharger in sight

Discussion in 'Model S: Battery & Charging' started by David99, Oct 23, 2019.

  1. cpa

    cpa Active Member

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    Unless of course Tesla decides to shave 20+ miles off range by capping the cell voltage at 4.09 instead of the initial 4.2 or by reducing Supercharger speeds by 50% so a 20%-75% charge takes an hour instead of 30 minutes or so. If Tesla can do this sleight-of-hand without explanation to those cars that are part of the aging fleet, who know what Tesla might do in the future with their newer models?

    Those of us who are subject to one or both of these limitations are enjoying our cars less and less despite our assiduous attention to our battery's health.
     
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  2. Evoforce

    Evoforce Active Member

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    #42 Evoforce, Oct 26, 2019
    Last edited: Oct 26, 2019
    For one thing, the Tesla BMS protects the battery from going to zero voltage. It cuts the battery off to protect it from over discharging. It cuts the power within the acceptable range of voltage to not let it over discharge or overcharge.

    Most if not all of the people complaining have a legitimate complaint. We don't know the truth behind what Tesla is doing with #chargegate and #rapidgate. You are making accusations and assumptions that are not founded.
     
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  3. Evoforce

    Evoforce Active Member

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    A model S will tow Great!
     
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  4. Babaron

    Babaron Member

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    Since the owners manual clearly states the Model S is never to be used for towing, I can’t help but wonder if the shutdown was premature due to the increased load on the battery due to the trailer. I believe the OP suspected this as well. It makes sense.
     
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  5. Kenz

    Kenz Member

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    I like the idea of power limiting the car for the last few miles of range.
    Maybe if the car was power limited when it gets to 5% or less it would keep people from getting stranded or worse damage the battery.
    Maybe at 5% limit speed to 50 mph, at 4% limit to 40 mph, at 3% limit to 30 mph, at 2% limit to 20 mph and at 1% limit to 10 mph.
     
    • Disagree x 1
  6. idoco

    idoco Member

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    Same here. Arrived at SC while towing to discover that SC completely lost power just as I arrived. Next nearest SC was ~25 miles away in the opposite direction. Had to leave the trailer at the SC, drive to the nearest SC , then drive back to pick up my trailer.

    To add insult to injury I had to deal with mall security on the phone. They weren't happy about a trailer with no attached car parked in their lot.
     
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  7. Richthegolfer

    Richthegolfer New Member

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  8. VT_EE

    VT_EE Active Member

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    The OP likes to live on the edge. His experience is very helpful for the rest of us though.
     
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  9. David99

    David99 Active Member

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    I am a little more cautious now with pulling the trailer. The problem is without one you can drive with very low power. With a trailer you can't. So if it gets close you can try to slow down but you won't be able to get the consumption down enough.

    The other problem is that pulling a trailer (or going very fast without one) is discharging the battery at a higher rate. This will make the voltage drop lower thus making the entire process less efficient. And to make it worse, when a battery is discharged at a higher rate the voltage tends to drop faster at the end. You will see the power limits coming in earlier and stronger. Considering that I kept going normal with such high power draw, I think the car making it to 1 miles left was pretty good! I did a test a few months ago driving the car to the shut down point just to see how far I could go. I drove very carefully and it only drove 3 miles after it showed 0. So all things considered the BMS is calculating pretty good.

    Another interesting fact. When the car shuts down the battery percentage slides down. It showed -5% after one hour after the shutdown. The BMS gets confused. On the next supercharger sessions it would only charge to 92% and finish. When I drove to down to say 5%, the battery voltage that was much higher than usual for this percentage. So it seemed the entire scale of shifted. It stayed like this at the next 8 superchargers. Only when I arrived and charged it on AC, the BMS would finally adjust itself to normal.

    As for the gradual power limiting when it reaches zero. Tesla actually already does it. The power limiter goes down more and more as you get closer to zero. But it's just a small orange line and usually the limit is pretty high so it doesn't affect normal driving. I'm thinking more about a slightly longer grace period when it shuts down to be able to get to a safe place.
     
  10. CuriousG

    CuriousG Active Member

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    But if you've ignored all warning signs already, what good is another warning if you'll ignore it like a check engine light?
     
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  11. Evoforce

    Evoforce Active Member

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    #51 Evoforce, Oct 27, 2019
    Last edited: Oct 27, 2019
    You can get warnings but if you are not near a place to charge you are going to press it to get as close as you can get to the nearest charger. Towing is tricky to do as it uses a varying amount of energy based on the weight of load that you are towing as well as elevation changes and temperature drop, wind etc.

    I laugh that some just don't get that this can happen to anyone and especially while towing. When you can only get 80-115 miles per charge, and yes it does easily vary that much with the same load, it is challenging to find enough chargers along your route.

    You may have to face unhooking your trailer and coming back for it too while hoping that it or the load isn't stolen. The really aggravating part is when you get to a charger and it is not working. When you get such short range, you have to rely on other charging networks beyond Tesla Superchargers.

    All of that being said, Tesla is a great towing vehicle with a low center of gravity, plenty of vehicle weight, and lots of torque! Towing heavy loads long distances does take navigation skills to cover all of the variables and sometimes there are just surprises that pop up.
     
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  12. CuriousG

    CuriousG Active Member

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    I get that for someone that lives in Arizona where you have a limited amount of Superchargers available, but not for being in California or back east where Superchargers are densely packed. Until Superchargers are 25-50 miles away from everyone, towing should not be a first choice with a Tesla unless it's a relatively short trip or be prepared for long wait times since you have to charge more frequently.

    I was at a Supercharger a few weeks ago and I saw a couple had unhitched their cargo while they charged in a BevMo parking lot. They came back to hitch their load and it took quite a bit of time for them to get hooked back up. Since I've never towed anything in my life, I don't know what's involved. In that time, they were sticking out a bit in the parking lot and another lady had started to back out and hit their Model X. It looked minor as they just exchanged information and went on their way. Guess I should have offered my dashcam video of the event.
     
  13. cduzz

    cduzz Member

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    A question for someone who knows things --

    Is it possible that the car's preconditioning for supercharging kicked in and wiped out substantial fractions of the remaining range?

    Hopefully the preconditioning logic is "am I above 20%? If so warm up batteries."

    One of the central mysteries is "I had X% or N miles and suddenly it went to zero." This is exactly the behavior that the gauge is trying to avoid -- nobody cares (much) if you've got 200 or 203 or 199 miles left when you have 200ish miles left; everybody cares if they have 19 miles or 22 miles if the station is 21 miles away.

    I personally got to play the range game when I rented a Tesla a couple years ago; my family wanted to see crater lake and so we went; the car said that I'd have -15% battery when I got back. Uh Oh. There was a Destination charging station there, so we charged there and we left when the car said that we'd get to the next station with 10%, and I drove like a eco warrior prius on the way back, but it was still an anxious drive back for quite a while. I felt "safe" when I was 20 miles away and the car said that I would land with 20%.
     
  14. Rocky_H

    Rocky_H Well-Known Member

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    I am finding this odd how many people are suggesting that Tesla should "add" the feature of limiting power when the battery is low. They don't seem to realize that Tesla vehicles have always had this.
     
  15. cduzz

    cduzz Member

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    I think it is a matter of degrees; how aggressively does it limit power?

    If we're talking about features we'd like to add beyond fartmode, it'd be nice to have it (optionally) severely limit power once you hit 7%ish of battery capacity such that the max power is impossible to ignore.

    I've seen my car limit AC at below 20%.
     
  16. Joelgjr

    Joelgjr Member

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    LEFT THREADED IS NORMAL. this is not a Tesla thing.
     
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  17. hill

    hill Active Member

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    I could have written this comment over 1½hrs ago (especially knowing with the high winds that the utility company, rather than fix their aging infrastructure like laying power lines underground). In stead - it's written right now.... even knowing all too well I may lose pow
     
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  18. Bridor

    Bridor Member

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    My Tesla Model X died twice with 19 miles of range showing in the same trip. The first time it added eight hours to our trip (out of warranty with 150K miles) - I pushed it to a 110 plug and plugged in for an hour and then drove carefully to a nearby hotel that had a destination charger. They were gracious enough to let me plug in for a bit. The second time it died within a mile of the supercharger at Beaver, Utah. I coasted to within 20 feet of the supercharger and some people helped me to push it into a stall. It turns out my battery was unbalanced. I still do not know why the trip computer routed me through Utah from Washington with a 60D. Never again - I will go through California and on to Arizona from here on out.

    Brent
     
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  19. jimisbell

    jimisbell Member

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    OK. I admit I am sans Tesla.....for now. But I do have a 2000 Honda Insight. And I do have several gas cars. The Honda Hybrid has a gas engine when the battery goes dead. BUT I would NEVER run my gas tank down to 3oz of gasoline (that is three shot glasses full). 3 Oz of gasoline represents 1 mile. What am I missing here that Tesla drivers will run till only one mile is left? I try to get gas in my Lexus when it tells me I have 50 (Fifty) miles of gasoline left. Is the Tesla so reliable that you really think ONE mile is safe????? I dont have sympathy for you.......
     
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  20. imthiazah

    imthiazah Member

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    A little off topic but wanted to ask, how has your Model X held up with that many miles? Especially the FWD and the auto present front doors. I don't have the option to purchase extended warranty anymore and curious to know what to expect when I reach those miles.
     

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