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Unable to charge to 100% ?

Discussion in 'Model S: Battery & Charging' started by Screwbal, Oct 23, 2016.

  1. Screwbal

    Screwbal Member

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    So I don't want to keep stressing my pack just as an experiment so its safer to ask and see what the larger group has experienced. A few weeks ago before a road trip I charged to 100% and gave it plenty of time to top off until it quit charging on its own and when it did it was only up to ~99%. This was before 8.0 and with the old battery view in the car which made it easier to see probably and at the end the green bar didn't actually fully fill up.

    Is the battery not hitting 100% in the UI a software glitch, degradation or just a balancing issue?

    To folks who charge to 100% often or those who don't do it but for rare needs, Is the UI actually making it all the way to the top?
     
  2. outie

    outie Active Member

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    When I set it to a hard 90% (using a 3rd party app as the slider doesn't always stop precisely at 90), I see 89% when I get in the car next day. Likewise when I set it to 100%, I get 99%. Vampire loss? I don't know. I would like to know too.
     
  3. Fiver

    Fiver Member

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    Every time I go to 100 it stays there. Just remember once you get the "charging complete" message it actually stops charging. So if you hit 100% but then you let it sit for a bit it will start to drop it's charge and will show 99% after awhile. If you have heat or AC running for example, lights on etc etc. Heck mine loses about 10 miles of range in 12-14 hours of sitting, but I have always connected on, and a bunch of other stuff.
    Is it actually set to 100%? Mine often will look like the slider is all the way but using an app like Remote S I will see it's really only at 98% or something.

    If your car is programmed to go to 100% and it's only getting to 99%.. I might call service. Or run it down under 5% and then charge it back up to 100% and see if it's balanced out the pack and actually does get to 100% the second time.

    You probably are already aware that it's not good to let your car sit at 100%. As long as you drive off right away when it's gives you the "charging complete" message at 100% you are ok. (Drive off meaning you leave on a trip that brings you below 90% before you stop). A little time at 100% isn't that bad. Hours at 100% is not so great. Same goes for under 10% or so.
     
  4. Screwbal

    Screwbal Member

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    I had let it it sit for what should have been 15-30 min at this 99/100% mark to see if it was going to flip over however I knew I didn't want to and shouldn't leave it that full for long. Sadly finding the opportunity to take it down to less than 5% is going to be difficult if I ever do it as on trips the wife is super uncomfortable with it estimating below 10% :) Someday I'll find the chance to excessive it but I'm sure I'll get plenty of responses here before I find that window of time.
     
  5. TexasEV

    TexasEV Well-Known Member

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    Whether it says 99 or 100% is irrelevant because it's just an estimate anyway. No worries about it being "degradation" as the car estimates the percentage charge of the available battery, not the battery capacity before it was used. For example my original 60 started at 208 rated miles when it was 100% charge. Now more than three years later a 100% charge shows 200 rated miles.

    I would suggest you stop playing with the battery and just enjoy the car.
     
    • Like x 2
  6. 5thumbs

    5thumbs Member

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    On the 2-3 occasions that I've attempted a full charge at a supercharger while on a long trip, I get to 99%. Then it says "calculating time to complete charge" (or something similar), and it just sits there. After 5-10 minutes I give up but it would be gratifying to see it say "charging complete". Not sure if this is a problem with the battery but will bring it up at my annual service.
     
  7. Fiver

    Fiver Member

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    That last 1 or 2 percent before 100% takes ages. It will say 10 minutes remaining, then 20 minutes later it will drop to 5 minutes remaining, then 20-25 minutes after that it will finally hit 100% but charge for another 5-10 minutes before finally saying "Charge complete" at 100%.

    I don't do it often for this very reason, regardless of how far I'm about to drive. An extra hour of waiting isn't worth it for 5 miles. Also when I leave the supercharger, it starts dropping rapidly, like 1/2 a mile will peel off 5 miles from the rated range over mostly flat ground and mild driving.
     
  8. 5thumbs

    5thumbs Member

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    Fiver, Thank you for the information. It sounds like what I have observed is "normal".

    Jay
     
  9. rolson1011

    rolson1011 2016 P90DL, Model 3 on reservation

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    The scientific reason is that the battery resistance increases as it gets full. It's harder to stuff electrons into a full battery, so the charger has to slow down to a rate the battery can accept. Even charging to 100% on a 240V mobile connector, you will see the car taper off at around 99% to about 16A or less while it balances the cells. (good to do every now and then BTW) This is why the Tesla Navi automatically calculates estimated time needed for optimum charge speed along your route. I've found it pretty generous in the times indicated and far often exceed it's estimates.
     
  10. WannabeOwner

    WannabeOwner Active Member

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    My car has taken 30 - 60 minutes to get from 99% to 100%. I've assumed it was balancing the cells.

    I don't know if it is worse leaving it at 99.xxx% for the time it takes to finish and get to 100% (the increased range of 100% over 99% is of course inconsequential to me) ... or whether it is bad to interrupt the "balancing" process?
     
  11. mknox

    mknox Well-Known Member

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    I hadn't charged mine to 100% in a long time because it would seem to get "stuck" at 99 so I would just unplug. I was convinced by forum members here just to leave it and it would eventually complete. It did... but it took about 4 hours to go from 99 to 100 and stop! I assume I had a lot of balancing to do.
     
  12. immolated

    immolated Member

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    No
     
  13. 5thumbs

    5thumbs Member

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    Hmmm. I bet there is some advantage to "balancing" the cells. I did not feel comfortable or patient enough leaving it on a supercharger to get to 100% (only really needed for long trips). So next time I will charge it to 100% overnight at my home and then take off to burn off the juice. I suspect the balancing will help calibrate and/or maintain the health of the battery.
     
  14. WannabeOwner

    WannabeOwner Active Member

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    I think that may be the main benefit - better prediction of range / "empty"
     
  15. AllenWong

    AllenWong Member

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    Was the car "on", though? When I look at the battery drain using the Remote S app when the HVAC is on, it says that it's at around 3 mph drain. And when the charger gets near 100%, it charges at around 4 mph. So if you leave the AC on while charging, you could be stuck at the same % charge for hours because you're really just getting a net charge of about 1 mph or 0.25% per hour.

    What I do to get to 100% faster from 99% is to just exit the car and lock it. Then I let it shut off all HVAC and displays, and let it charge without any vampire drain. This usually gets me from 99% to 100% in 30 minutes (assuming that you're charging at 4 mph).
    It's vampire drain. I tend to lose about 10 miles of range every 2.5 days of not driving, so that's 4 miles per day, which is about 1.50% of battery each day (for my P85D).
     
  16. mknox

    mknox Well-Known Member

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    Nope. Just plugged in at work.
     
  17. SmartElectric

    SmartElectric Active Member

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    Please, stop stressing about stressing the pack.
    We have an original A-pack battery from an early 2013 build, one of the first few thousand Model S cars built.

    We've charged to 100% at least 50 times over the past year, left it at 100 overnight (10+ hours) quite a few times and still have 97% original range after 85000 km.

    My wife will not accept any compromises or inconvenience for the sake of "babying the battery" (as it were). She sets the slider to 100% the night before she does any significant travel, and never worries about the time the car sits at 100%.

    Our standard charge rate is 90% and the car routinely sits near that for days on end. It's a "garage queen" car that does 50 km during the week and 250+ km most every weekend.

    My advice : Don't stress. Just charge and drive. Please. I urge you to feel confident Tesla has engineered the battery systems so you don't have to self manage it.
     
    • Informative x 1
  18. m2140

    m2140 Member

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    I"m having the same problem. Set the car to charge to 100% and the completes charging at 99%.

    The car actually states charging is completed at 99%. This is not it charged to 100% and i get into a little later an have 99%. For what ever reason the car could not charge to 100%. So I started to track every single charge attempt to find a cause.

    I've been tracking the charging for over 3 months now and I only get the reduced completion charging when the temperature is cold. under 50 degree F. Sometimes I would get as low as 96%. Really got me concerned.

    So It's been in and out of the service center and they have not been able to find the cause. They tried recalibrating the charger and I went thru a couple of Low to High charge cycles before trying 100% again. The charging got worse and it happened more often.

    Tesla Service center & engineers were at a loss and they figured the problem was due to the battery because charging completed at 99% at my local supercharger.

    So I'm a month in with a brand new battery pack and I still have the problem. It's not as constant because the weather warned up here in Cali. But on cold nights when the temperature drops, I cant get 100% battery and again charging completes at 99%.

    I have a 2015 Model S 85D with Dual Chargers & 43,000 miles.

    She is going in Wednesday again to get some work done at the Service Center (new seats) . I've logged all the dates & times the charging ended early. What else can I do to get this resolved? This is technically the 3rd time in to take a look at the issue. But I would have brought her in more if they would allow me but since engineering is at a loss to the problem they won't let me come in until they have a next course of action.
     

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