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Charging speed to 100% dramatically slower!!!

Discussion in 'Model S: Battery & Charging' started by sorka, Mar 7, 2018.

  1. sorka

    sorka Active Member

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    Last time I charged to 100% last year, it held 80 amps all the way up to 99% before tapering off to the "calculating remaining charge time" when it would drop to 20 amps or so for that last little bit.

    This time it dropped to:

    72 amps / 90%
    43 amps / 93%
    40 amps / 94%
    23 amps / 96%
    16 amps / 98%

    Instead of the usual 19 minutes to charge from 90 to 98%, it took well over an hour to get to 90% and another 40 minutes to get from 98% to 100%.


    [​IMG]


    Software change or battery degradation?

    Also, my max power output at 90% with max battery 5 minutes from being ready, i.e. not fully heated has dropped from 458KW to 436KW. I've lost HALF of my Ludicrous upgrade since about 4 months ago.

    Also, I'm getting regen limit with triangle when coming down from Pinecrest for the entire trip which means I'm using my breaks far more than I used to.
     
  2. FlyF4

    FlyF4 Member

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    Actually I am surprised that you say it charged at 80 amps all the way to 99% in the beginning. The numbers you report now are more along the lines of what I expect. Even that is good.

    You do know this depends on a LOT of variables....mainly temperature of the batteries and other factors, right?

    Oh and I edit to add, loss of regen is not a new thing when you are at the top end of the charge rate.

    Aside from that. I highly recommend to stop charging to 100% unless you are going back out on a long trip and run down that charge by at least 10-20%.
     
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  3. BerTX

    BerTX Active Member

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    Memory is a funny thing. Sometimes you forget things that happened. Sometimes you remember things that never happened.

    If this is truly a change that happened to your car, buy Tesla some donuts because they saved your battery from certain destruction.
     
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  4. FlyF4

    FlyF4 Member

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    hee hee. funny man. I always laugh at your posts.... yet right on track. Glad you said this. As far as I know the firmware has NEVER allowed the batteries to charge at that rate to that percentage even under the most imaginable cooling efforts. Right, it could literally destroy the packs.
     
  5. sorka

    sorka Active Member

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    #5 sorka, Mar 7, 2018
    Last edited: Mar 7, 2018
    Battery temperature ranged between 70 and 80F. Is that too cold? Regardless, I've always gotten 80 amps up to that point on very hot or very cold days.

    I've charged to 100% perhaps 6 times in the 50K life of the car.

    As far as regen limited, I've made the same trip from my vacation house in Pinecrest a dozen and half times and never experienced regen limit (except starting out) in any condition including freezing temperatures or 100F degree days until the first time this fall. Have made the trip 3 times since and have had the same limit now all starting the trip with 90%. The limit always kicks in on that last grade before I hit Sonora.

    This is the battery temp when I came to the first red light entering Sonora when regen limit with triangle first kicked in:

    [​IMG]

    It started out around 50F and was regen limited due to cold for about the first 5 miles and then lifted as the battery hit mid 50Fs.
     
  6. FlyF4

    FlyF4 Member

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    I guess you mean ambient air temperature. There isn't a way for the customer to know the battery temperature. Other than that, I don't know what to say. I have never heard of a Tesla charging that high of amperage at that percentage. Talk to your service guy about this, but don't get angry at him if he asks if you are suffering from memory loss :D Something unusual going on in my opinion. you should not want it to charge at that high amperage near the top end anyway. Best
     
  7. thefortunes

    thefortunes Member

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    Guys, he's not talking about supercharging here.

    I have only charged to 100% four times, but I looked back at my data and, sure enough, I used to keep full power (which for me at home is only 40A) right up to 99%. The last time it started tapering at 93%. Must be a firmware change.
     
  8. FlyF4

    FlyF4 Member

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    yes yes, I know he is talking about a destination charger. My comments still apply. I can believe this happening for as many as 10 charges, but not after that. It is not a firmware change. It is a charging algorithm :)
     
  9. sorka

    sorka Active Member

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    No. I did not mean ambient temperature.
     
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  10. brkaus

    brkaus Active Member

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    Mine has occasionally slowed going above 98%. But not always. I assume it has to do with balancing and the way full is measured.

    Longer term go between charging to full, the longer full takes.
     
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  11. sorka

    sorka Active Member

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    That's what I'm hoping and I'd be OK with it if that were the case as I rarely charge to 100% and when I do it's usually before going on a long trip where I have plenty of time to plan and charge first.

    What I really want to know is if anyone else can charge like I used to with an HWPC or if everyone is now seeing this new behavior. i.e is it a firmware change or is it just me :)
     
  12. thefortunes

    thefortunes Member

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    Just like "there is no way for a customer to know battery temp"? Lol.
     
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  13. sorka

    sorka Active Member

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    But nothing like the picture I showed, right?
     
  14. thefortunes

    thefortunes Member

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    Mine (first 3 charges to 100% with tapering at 99% and last with tapering at 93%) were also on an HPWC, albeit at a lower amperage to start with.
     
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  15. brkaus

    brkaus Active Member

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    I recall it saying over 2 hours to finish from 98%, but it ended up taking about 55 min.

    It was the two hours that captured my attention. Sorry, I don’t really recall more details. I’ve only charged to 100% 3 times in a year.
     
  16. sorka

    sorka Active Member

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    OK, well that's starting to look more and more like a firmware change.
     
  17. FlyF4

    FlyF4 Member

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    Oh ok. Help me. Are you talking about battery temperature through accessory app or something else?
     
  18. FlyF4

    FlyF4 Member

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    I've gone back and looked at firmware changes... no not the summary reported in the vehicle. The detail changes and I see nothing to indicate this is a firmware change. Yes, there are firmware changes related to charging yet not related to what you mention. I can see that the algorithms can account for changes as time goes along. Bottom line is this is a common behavior, so if you are concerned, I would not be. Perhaps you are really observant and just curious? :)
     
  19. sorka

    sorka Active Member

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    I'm talking about the battery temperature of EACH string logged through the CANBUS. In my case, I'm using an Elm327 dongle with an adapter cable I made to Tesla's CANBUS connector. I'm using TM-Spy just like almost everyone else :)
     
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  20. sorka

    sorka Active Member

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    I'll hold my judgement on whether it's common until more folks have reported in on whether they've also seen this change in charging behavior.

    Tesla has a history of not disclosing most of their changes unless it's feature enhancement related.
     
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