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If you fast charge, Tesla will permanently throttle charging

Discussion in 'Model S: Battery & Charging' started by Naonak, May 4, 2017.

  1. Naonak

    Naonak Member

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    Hi everyone. I just got off the phone with Tesla with some disturbing news.

    My car has approximately 30,000 miles on it. I regularly use CHADeMo to charge my car, with the occasional Supercharger charge on road trips. On my last road trip, I noticed that my supercharging rate was significantly reduced, usually staying between 75 kw and 90 kw. At first, I thought it was the station, but each Supercharger on my trip had the same behavior. So I bought my car in for service last week.

    After the technicians went over the and presumably consulted with the mothership, it was determined that the car has now entered a permanent degraded mode where it will no longer allow fast charging to "prevent battery degradation." Read that again... that's right... if you use Superchargers or any DC Fast Charging, including CHADeMo, your car will eventually enter into a permanently degraded mode that will prevent you from charging your car at reasonably fast speeds.

    I am, to say the least, livid. I am waiting for a call back from management, but presumably, they are going to explain to me that there is nothing they can do. This is akin to the Ludicrous launches being restricted, without warning or any communication from Tesla. But this... is much worse.

    It's worse because it affects every Tesla vehicle. Every Tesla, not just Ludicrous mode Teslas, will permanently and irrevocably degrade their charging capabilities if you use DC Fast Charging of any kind more than the unusual rare occasion.

    I'm honestly speechless at this. To the best of my knowledge, it has never been communicated from Tesla, until now, that using any kind of DCFC will permanently degrade your vehicle. Yes, we all know that charging to 100% regularly is a bad thing, but just regularly DC charging is also apparently just as bad, according to Tesla. But to make matters worse, it's not the battery that's degraded or causing the slow down, it's Tesla's charging algorithm that will slowly start to degrade your charging on each "count" of DCFC. According to the tech I talked to, there is an internal counter that increments each time you DC charge, and once that reaches certain thresholds, it starts restricting your top end charging ability. Presumably, if one keeps charging DC, over time, you will be restricted further and further.

    This, ostensibly, to prevent Tesla from having to pay out to replace degraded batteries under their unlimited mile warranty. So over time, it will take longer and longer to charge your car. Already, this adds a significant amount of time to my road trips by restricting my charging from a previous high of 117 kw to ~90 kw on a good day. Road tripping in my Telsa already takes 2x as long as a gas car, but now it's taking even longer. I can't imagine wanting to take this car on any further road trips at this point.

    Tesla needs to do something about this. This is not ok. It is not ok to remove critical functionality from the vehicle, every vehicle, without warning and without prior notice. I simply would not have purchased this car if I was informed that it would lose the ability to charge the battery over time, especially such a short time frame (1 year / 30k miles).
     
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  2. vrykolas

    vrykolas Member

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    This is the first I've read of this, and is counter to all the evidence we've seen so far on the forums, spreadsheets, videos, etc.

    If this were true, I would also be quite upset... but there must be some explanation to this (incorrect data? mis-informed technician?)
     
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  3. Max*

    Max* Banned

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    I have 36k miles on it, and I'd estimate about 1/3 are supercharged miles. I need to see what the max output on the SpC is now... because by your theory, I should be degraded too.
     
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  4. Drone Flyer

    Drone Flyer Member

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    I think you've been led in the wrong direction by misinformation.
    This is simply not true!
     
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  5. Naonak

    Naonak Member

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    It's not a theory, this was direct from Tesla. They told me because I had so many DC charges, the car has limited the charging capabilities. Virtually all of my miles are DC charges. I very rarely charge AC. They did not specify exactly what the limit was, but I will try to get that information.

    So are you saying Tesla is lying to me? To what end? Why would they do that?
     
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  6. cdub

    cdub Future Model 3 owner / Current original Leaf owner

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    Why don't you use AC? Exclusively DC? No plug where you live?
     
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  7. Xenoilphobe

    Xenoilphobe Active Member

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    Unfortunately at the mileage rate you are going the car isn't going to worth much, you have lost $30K in one year of driving - next year it will be $60K and the following $90K. (Assuming Tesla's trade in calculator and you sustain this mileage rate)

    Also you might want to read the battery section of the warranty... there are no stats on the charging rate - in fact the earlier superchargers couldn't even charge at the rates we are discussing today.

    10 more minutes will not kill me to get 300K miles out this car. Also I'm at 60K on a March 2014 P85+, mine isn't doing this... are you sure this guy knew what he was talking about? What size battery do you have?
     
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  8. electracity

    electracity Active Member

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    If it's true, it is chemistry. There is nothing Tesla can do about it except offer compensation. But I'm sure they are covered somewhere in the fine print.
     
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  9. ChadS

    ChadS Petroleum is for sissies

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    #9 ChadS, May 4, 2017
    Last edited: May 4, 2017
    This doesn't sound good, and I certainly understand why you are unhappy. Still, this is clearly not true as written; many of us have Supercharged hundreds of times and not hit this limit. My wife's car has 82k miles and we have Supercharged over 250 times. I am nowhere even near the record-holders.

    That is a very different than just using DC on more than an unusual rare occasion. While we have Supercharged many times, most charges are still AC. We will all be very interested to learn what you hear back. I wonder if the percentage of charges counts as well as the number of charges? Maybe it needs to charge on AC every so often to balance? Just a thought; I too wish Tesla would just tell us so we don't have to guess.
     
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  10. Chopr147

    Chopr147 Active Member

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    First I'm hearing of this and i'm a Tesla sponge when it comes to information. Not saying you are wrong. I certainly hope you are though. No offense :)
     
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  11. Max*

    Max* Banned

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    There have been a lot of cases in the past where Tesla says one thing, then later it turns out it's something completely different.

    I think we're all just trying to get more info. So far you're the first person whom Tesla has mentioned this to. And this would be a big hit to EVERY Tesla driver, so it's a big deal.

    The Tesloop taxi driver who drove the Tesla for 200k miles and supercharged daily didn't mention any sort of slowdown. And I'm sure he'd notice. There are multiple drivers on TMC who put over 100k miles on their cars, a lot of them supercharged, who never noticed a slowdown.


    So I can understand people's skepticism. I think everyone believes that you were told this information. People are going to question whether the information is valid or not.
     
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  12. cgiGuy

    cgiGuy Active Member

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    Can you give us ballpark number of DCFCs you've done in 1 year/30k miles? If you charged after depleting 200 miles each time (average) that would be 150 times in 1 year.

    Just trying to put things into perspective, for anyone else that might want to compare charge rate.
     
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  13. Naonak

    Naonak Member

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    This was the first I had heard of it as well. The Tesla tech told me that it was communicated many times to Tesla owners. I told him that is simply false... Now I'm waiting on a call back from management.

    I will try to get something in writing from them regarding this. I was as flabbergasted as everyone else here seem to be when they first told me... I will definitely be following this up to its conclusion one way or another because my car is not usable in the manner in which I purchased it at this point.

    I hope the techs at my SC are misinformed and it's something wrong with my battery or charging system. They seemed pretty confident though.

    As to how many DC charges I have:

    6,685.603
    Energy (kWh)
    245
    Total Charge Ups

    That does not include Supercharging. You can add probably another 50 - 60 Supercharges to that I would estimate (I can get an exact number at some point, I have records). That number above is 99% CHADeMo charging since March 2016.
     
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  14. Xenoilphobe

    Xenoilphobe Active Member

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    Also aren't all charges DC? Everything that touches that battery is DC, even the HPWC which hits the onboard chargers and gets converted to DC. CHADeMO might be the issue - here on the east coast those things are always acting up - very poorly maintained and could be disruptive to the Tesla charging system. Who knows... my bet is this car is a 60 and heavy High Voltage DC charging may have a greater impact on a smaller battery... just a guess..
     
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  15. oktane

    oktane Active Member

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    #15 oktane, May 4, 2017
    Last edited: May 4, 2017
    Perhaps this explains the throttling at supercharges. Maybe some algorithm as to number of slow home AC charges vs. fast DC charges to prevent warranty claims on batteries?

    In general, lithium ion batteries should be charged at a C-rate of 0.8 or less. I haven't done the calculations to determine what that rate is without looking up capacity/voltages of Tesla packs.

    Lithium ion packs degrade with every discharge cycle. I would assume there is a software buffer to allow for planned degradation. You lose about 10% capacity with 500 discharge cycles. I haven't studied this recently, so take what I am telling you with a grain of salt.

    If the OP has had a lot of cycles on his battery, and is charging at high C-rates, he will need a new pack soon.

    IMO it is fraudulent for Tesla to use software to limit car performance or charging to save on warranty claims. They need to either establish policies at the sale of the car, or "suck it up" and pay for replacement parts on users that need it.
     
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  16. Naonak

    Naonak Member

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    My car is a 2015 P90DL. At the battery level, all charges are DC (they have to be), but DCFC (Superchargers included) bypasses the converters and directly charges the batteries at a high charge rate. L2 and HPWC chargers go through the AC to DC conversion at a much slower rate.
     
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  17. electracity

    electracity Active Member

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    Musk has said that the typical Tesla has the equivalent of one battery cycle per week. So about a 10% degradation from charging in 10 years. That performance seems acceptable to me.
     
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  18. cgiGuy

    cgiGuy Active Member

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    Wow.. that's a lot.
     
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  19. Jeff N

    Jeff N Active Member

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    Lithium ion battery have two largely independent modes of degrading: per-cycle and calendar time. That's why the following paragraph from a Fred Lambert article this morning at Electrek is off-kilter:
    No, it doesn't mean that at all. After 25 years of calendar degradation you will almost certainly lose far more than ~5% even if you never cycle the battery.
     
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  20. ThosEM

    ThosEM Space Weatherman

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    I would caution against using the charge rate at a supercharger as a metric, because it can and does vary for quite a few reasons, it seems. Hot weather in particular seems to reduce the maximum charge rate, especially, but there seem to be other factors that are difficult to get arms around. Since you have only been running it one year, you may be experiencing an annual temperature variation.

    I got quite alarmed when the rates slowed down during 100F weather last summer, but cooler weather relieved that. It isn't clear exactly why, but there are a number of components that are protecting themselves from overheating, from the battery itself, to the switchgear in the car, to the charging cable and fill connector, to the supercharger and its rectifier banks. And one suspects the utilities may be making peak rate charges in hot weather that Tesla is seeking to avoid. Tesla states that some specific charger bays maintain high rates in hot weather better than others and that they track such information and can relay it by phone, or one can simply try another bay if slow charging is encountered.

    Given that Tesla is not telling us the whole story here, I'm very skeptical of the story you got about permanent changes in the software.
     
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