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Car says charging is complete even though it isn't

Discussion in 'Model S' started by Mike K, Jul 10, 2016.

  1. Mike K

    Mike K Member

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    So we're about to head out on an 8 hour road trip and I range charged the car. 2013 s85 with an A pack. It range charged fine for the trip here to 256 miles, exactly what it's been since I've owned it but now I'm having an issue.

    The car is currently at 98% and says charging is complete. I can unplug the cable and plug it back in and it might immediately say charging is complete or it might start charging. When it starts charging it says it says it has 1 hour and 35 minutes left (110v) which is spot on to get the last 6 miles it needs but then I check it 5 minutes later and it says charging complete.

    Where am I'm going wrong here?

    Cliffs: Tesla's app says charging complete even though the battery bar is not filled and the car is not fully charged. Remote S says the car is fully charged but shows the battery at 98%. I have verified that the charge rate is set to 100%. It simply isn't accepting a charge. No errors.
     
  2. Mike K

    Mike K Member

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  3. jerry33

    jerry33 S85 - VIN:P05130 - 3/2/13

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    1. Battery SOC is always an estimate, it's not like measuring a volume of liquid.
    2. Unplugging and plugging back in may start the pack balancing if the balancing circuitry happens to be active.
    3. Automotive gauges have never been laboratory quality.
     
  4. S'toon

    S'toon Knows where his towel is

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    Bjorn discusses battery balancing.
     
  5. MGMDaware

    MGMDaware Member

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    Ok, forgive my ignorance on this. I watched Bjorn's video and think I have an understanding of the issue, but I have a question . . . .

    If I have an unbalanced battery (say, only charging to 98%) and I need/want to balance and get to 100% (maybe I need the miles for an upcoming road trip), should I plan and prepare in advance and start balancing a week or 2 prior to said trip? In other words, in order to get 100% of my miles on an otherwise unbalanced battery, I need to charge to 100% multiple times over a week or two?!?!?!?!

    or . . . . .

    even though it only says 98%, am I actually getting 100% range?

    Thanks in advance!

    -MG
     
  6. evp

    evp Nerd

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    Sometimes you need to discharge down to 10% or so to allow the battery management system to figure out the true state of charge. Give it another shot after your trip is over.
     
  7. msnow

    msnow Active Member

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    I've had this happen to me twice in the last two months. What I did was recalibrate by driving down under 10% and then doing a full 100% charge. It eventually calibrated and I got a full charge.
     
  8. Mike K

    Mike K Member

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    I appreciate the input guys. I don't think this is battery balancing though. Let me explain why:

    1. I regularly (once every couple months) discharge to 10% and then do a range charge. Just last week in preparation for this trip I did that.
    2. In Bjorn's video you can see that even though charging has slowed at 97% SOC, the car is still charging. My car is not charging. It states that charging is complete. Everything I've seen from battery balancing shows that the car still says it's charging as it's happening. Indeed, that is the only way it can balance. My car is pulling no power when this happens so it can't be balancing the battery as it's not pulling any voltage.
    3. I understand variances in rated range and how balancing can affect that but I don't recall people getting variances in states of charge in addition to that. By the car's own measurements, it's not showing a 100% SOC. It's showing 98% and when it's plugged in it will say how long it has to charge which might be an hour but then it stops after a moment.
    If anyone has any other ideas I'm open to hear them. I'm nearly certain this isn't pack balancing though.
     
  9. Mike K

    Mike K Member

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    Just for the sake of clarification, you had it's complete a charge below the percentage level set? I.E. you had it set to charge to 100% and it stopped at 98%?
     
  10. Don85D

    Don85D Member

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    For my trip planning I charge fully the night before but always leave 100 km (60 mi) of capacity just in case my planned recharging stop is out of order. To start off the trip a couple of percentage short is not an issue as I have a reserve that more than covers that. It also covers those windy or cold days when consumption is higher.

    I know that some Tesla owners like to run down to the last few miles then charge just enough to make it home with a mile or two to spare.

    I like having reserve capacity.
     
  11. msnow

    msnow Active Member

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    Exactly. The first time it went to 99% and said "charging complete" like yours. I tried disconnecting the charger and reconnecting and it started and then stopped. The next day I drove to 90% and when I got back in the car the guage said 91%. My SvC told me it would self-adjust and it did. The next time I did a 100% it was normal. It happened again after a deep discharge and full charge cycle except this time it said "charging complete" at 98%. Again it eventually reset to the correct %. Like you I knew it wasn't a 100% both times because my rated miles was lower than it should have been. Suggest you email [email protected] explaining the issue.
     
  12. BertL

    BertL Active Member

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    #12 BertL, Jul 11, 2016
    Last edited: Jul 11, 2016
    OP, similar to @msnow: What you are encountering is not unique to you. I have had the same thing occur, and it's always been when I'm trip charging to 100% -- never when I've being doing normal charging to 90%. In the trip charge situation, at least once I caught the "charging is complete message" having appeared, but my HPWC was clearly still charging my MS for another few minutes. I don't want to care about the technicalities of battery technology (like the future masses won't), thus I consider this a discrepancy (error?) in Tesla's firmware not representing when charging is really complete from the Owner's POV.

    I generally charge to 90%, and have trip charged up from there to 100% less than a dozen times since taking delivery last October. I've learned that when I do trip charge, it may take a VERY LONG time (as in 20-30 mins or more -- sometimes less) to get those last 2-3% points of charge and the real charging is completed (aka my HPWC goes off). Assuming battery pack balancing is going on, it would seem at least with my early S90D pack that the time it will take is not well predicted, and real charging completion is not presented by existing firmware correctly for every scenario. As such, I now allow an hour to get from 90%-100% with my Dual Charger and 80A HPWC ...but even then, my perception is Rated Range drops much faster the first few miles I drive compared to when RR is in the lower 90-percentile and below. When I do trip charge and hit 100%, generally RR will drop a couple of miles within minutes of completion, untouched sitting in my garage. All of that just reinforces my opinion that what Tesla is representing with Rated Range and "100%" is an estimate at best, and as you reach the top-end of charge, what your MS presents is not as accurate as when it's closer to the 90% mark or below.​

    All that to say, you are not doing anything wrong. IMHO it's (another) bug with Tesla's firmware. If you really want to charge to 100% upon occasion, great -- in your planning, just pad the time you expect it will take to complete. If you end-up not being able to wait, even though your MS may not have finished any pack balancing it's doing at the very end, you can still unplug and go on your way. I agree with @msnow though, your email to Tesla Service (be sure to give them your VIN and a date/time of when you saw this happen so they could check your logs) will add another owner voice to these problems -- hopefully causing resolution one day for more of us.
     
  13. Mike K

    Mike K Member

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    I appreciate the responses guys. I couldn't find anything when searching so my immediate concern at the time was that it wasn't going to supercharge and I was going to be sitting in the middle of the desert with an un-chargeable car. It was fine through the trip though. I'll report back when it's charged up again as well.
     
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  14. CHG-ON

    CHG-ON Still in love after all these miles

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    My understanding, from info I got here, is that if you charge to 95% or higher for three cycles, the battery will rebalance. Unfortunately, I have not had a chance to confirm this with long drives, just around town stuff. My 90% charge range did increase from 228 to 236. So I think it did change the measurement. The one thing that I try to keep in perspective is that 2% of 265 is 5.3 miles. Yes, those could be critical miles. But I always try to keep a healthy buffer because I simply don't trust the tripplanner enough to cut it that close.
     
  15. msnow

    msnow Active Member

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    That's right but it triggers at 93%. Never heard of it requiring 3 cycles though.
     
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  16. CHG-ON

    CHG-ON Still in love after all these miles

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    Thanks! I'll keep that in mind.
     
  17. msnow

    msnow Active Member

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    Think I got that info from @wk057 who is both knowledgable and reliable.
     
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  18. CHG-ON

    CHG-ON Still in love after all these miles

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    You bet he is. I always look to @wk057 and @jerry33 for solid advice.
     
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  19. msnow

    msnow Active Member

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    Agree. I'd also add @FlasherZ and @Ingineer to that list. I'm sure I'm missing others and I apologize in advance for that.
     
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