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Idle Battery Drain

Discussion in 'Model 3' started by kwest2, Dec 10, 2018.

  1. mswlogo

    mswlogo Well-Known Member

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    Start a change.org petition or something. I think your way off topic here, regardless of your good intentions.
     
  2. Jedi2155

    Jedi2155 Model 3 has Arrived.

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    I think its a consequence of Tesla making a "connected" vehicle combined with their intense TMS protecting their batteries. One thing for sure is if the battery data showing Tesla's degradation to date is accurate, they are above and beyond every other EV maker in capacity retention.

    Sure it might cost 30-40W average power draw, but compared to the potential capacity loss without a strong monitoring system I'd take that. Plus I love all the "connected" features that Tesla offers at a relatively fast response rate compared to OnStar and other systems.
     
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  3. AlanSubie4Life

    AlanSubie4Life Efficiency Obsessed Member

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    I thought the topic was battery drain and what was normal? Surely what normal battery drain you should expect would come into that. I contributed with a side comment about what is normal (and it is a negative for some users!), and more to the point, a relevant question about whether there is data on cold weather battery state and how rated range depends on battery temperature (which is highly relevant to the topic here).
     
  4. AlanSubie4Life

    AlanSubie4Life Efficiency Obsessed Member

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    #24 AlanSubie4Life, Dec 10, 2018
    Last edited: Dec 10, 2018
    Sure, that clearly is a contributor since idle mode is the dominant factor here, I just think it would be good to have more control. I think if Tesla were incentivized to make it better they would.

    EDIT: Since we can always connect to the car already (albeit sometimes a little slowly), it appears sleep mode (about 12W) is adequate for connectivity. That would be a huge improvement. Just need to get rid of the spurious occasionally long idle mode (150W or more as you say) periods. Tesla could do this today presumably and this would be good enough for a lot of people. And presumably we wouldn’t lose any functionality.
    End edit.

    As far as the OP goes, to get back on topic:


    @kwest2: for your debug, it would be interesting if you have a chance to let the vehicle sit for two days, to check the vehicle drain per day on two subsequent days. The first day might involve the effect of a cooling battery (log the delta). Then the second day should be entirely vampire drain, assuming the outside temperature is similar.

    It’s possible Tesla will do a hard reset and fix your problems too.
     
  5. eloder

    eloder Active Member

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    Long-term battery health and protection is a good reason for the vampire losses, though, when it comes to hot and cold weather. The Volt, as I understand it, never suffered range loss because it had a tremendously oversized battery that unlocked more usable capacity over time.

    The Volt for example has 0.8 kwh more than my car, but something like 10% less range after adjusting to the difference in EPA efficiencies.

    Some other EVs like the Leaf fare extremely poorly in the heat and are great examples as to why you should condition batteries proactively. Leafs in hot climates could lose over 30% of their battery capacity in the course of a few years and 50k miles. Even their new battery chemistry isn't that great in hot climates and sees double digit percent capacity degradation over the course of a few years. I remember stories of Leaf owners who would intentionally let their car sit outside their garages and outside of shaded areas so that they could degrade their battery enough to warranty replace it before the four year mark.


    My car also has vampire loss, though its battery protection only kicks in under 10 degrees F or so. It'll vampire drain as quickly as a Tesla (percentage-wise) in colder weather then. It's still getting a noticeable range loss over the course of just a year. In temperate weather though it would maybe lose a mile of range over a month (no cellular connectivity, no passive entry).

    However, I do agree with you that Teslas consume far too much battery when they are sitting in nice temperate weather. I've had EVs with cellular connectivity and passive entry before that would take a week to lose a mile, which makes sense because you can have a smartphone idle for days on a battery 1/7000th the size of a Tesla.
     
  6. mswlogo

    mswlogo Well-Known Member

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    Do you know how many coal fire plants it's taking to light the silly characters you're typing?
     
  7. Jedi2155

    Jedi2155 Model 3 has Arrived.

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    I was talking to a Tesla engineer and he basically said that vampire drain was the result of trying to keep a bunch of babies from crying and waking up. I'm wondering as to what in the design would cause such a big drain the first place and I'm thinking is either the traction pack constantly being connected and charging the 12v battery or fact that they have to turn on the entire Vehicle Controller to do simple functions rather than a low power SoC.
     
  8. AlanSubie4Life

    AlanSubie4Life Efficiency Obsessed Member

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    I don’t follow the babies reference.

    I think the 12V battery can’t be it - surely a battery tender doesn’t draw 12W average when the battery is fully charged (this could be measured with a Kill-A-Watt by someone with a proper battery tender).

    But the latter seems conceivable. Though the fact that you can roust the vehicle from sleep mode implies there is something relatively low power (12W or less anyway...which still is a bit much) that is always listening, so that is promising!
     
  9. Daniel in SD

    Daniel in SD Well-Known Member

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    How many?
    Now I want to know how much energy it takes to post on TMC. I guess that would be off topic though.
     
  10. noicepls

    noicepls Member

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    If vampire drain is to be included in MPGe ratings, then to be fair, losses due to fuel evaporation should be included in gasoline cars too. However, since this is not easily measurable (e.g. gasoline fuel losses depend on several factors such as temperature/humidity etc.), it's probably better to not worry about including vampire drain in MPGe ratings either.
    Also, I recommend Tesla installing solar roofs in their cars next year to minimize/eliminate vampire drain by diverting solar power to dealing with vampire drain exclusively as the car sits out there in the elements.
     
  11. AlanSubie4Life

    AlanSubie4Life Efficiency Obsessed Member

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    #31 AlanSubie4Life, Dec 11, 2018
    Last edited: Dec 11, 2018
    Fuel evaporation is not a big issue in a modern vehicle unless perhaps you live somewhere extraordinarily hot. It’s not even a problem during fueling anymore, at least in states which care about things like air quality. If it were, it would be a big problem! I have a garaged gas burner which I rarely drive, and I am certain that the evaporative losses are completely insignificant. Another thing to note is that whether it is significant or not, it would apply to ALL vehicles roughly equally (E85/flex fuel/diesel might be different but whatever...). And there are definitely laws/rules to control this evaporative problem!

    Solar panels are kind of unnecessary and doesn’t solve the problem for garaged vehicles, and vehicles stored out of the sun.
     
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  12. ezevphl

    ezevphl Member

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    I would love to see an official chart of expected battery drain in a certain temperature range. Like right now my car is at a body shop, it was in the 20s overnight and its not plugged in. At this rate of loss I will need a charge before getting home.
     
  13. Jedi2155

    Jedi2155 Model 3 has Arrived.

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    I used TeslaFi to track my losses, quite valuable. Examples:

    Yesterday I was checking my car a bit since I was planning on picking it up from the service center today:

    upload_2018-12-11_14-22-40.png

    The weekend before, the service center was closed and these are my daily losses:
    upload_2018-12-11_14-23-6.png upload_2018-12-11_14-23-24.png
     
  14. AlanSubie4Life

    AlanSubie4Life Efficiency Obsessed Member

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    #34 AlanSubie4Life, Dec 11, 2018
    Last edited: Dec 11, 2018
    Interesting. Your numbers are considerably lower than the prior data I saw, particularly for sleep mode (that's where I was getting the ~12W sleep/ ~150W idle numbers). Idle isn't that different, usually around 100W or so for you. Sleep mode is really low for you though - just a couple watts! If only we could have a mode where we discourage the car from going into idle mode, things would be pretty good. Sigh. And if only we knew what exactly the car was doing in these idle modes, and whether it was actually necessary... It certainly doesn't seem conceivable to me that it has anything to do with TMS - that minuscule amount of energy isn't going to be enough to thermally manage anything!

    This thread (link to the specific post of relevance) has the prior data, from @OverJohn - he was in NorCal, car in a garage, but I do not know the ambient temperature which could have been a factor I suppose (though I can't conceive of how for such a relatively small difference - again, I would expect TMS to have a massive impact when it kicks in):

    Vampire Drain/Loss Tracking
     
  15. ConcordeSST

    ConcordeSST Supporting Member

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    #35 ConcordeSST, Dec 11, 2018
    Last edited: Dec 11, 2018
    Here is my data from yesterday (ambient temp 24F) . The snowflake idle periods are when I'm preconditioning the cabin. The idle time with HVAC off is 2hrs 10min.

    736295E4-0A9A-4B11-8E40-2F9460BDBE01.jpeg
     
  16. eloder

    eloder Active Member

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    Well, Tesla does have one unique characteristic--it'batteries are thousands of individual small cells, rather than a handful of big pouch cells.

    Maybe those are the babies he's referring to, combined with a temperature management system?
     
  17. animorph

    animorph Active Member

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    I figured the babies would be the customers who complain that the car isn't instantly ready to go as soon as they open the door. I think if the car is sleeping it can take half a minute to boot up. That readiness is another reason for vampire drain.
     
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  18. Jedi2155

    Jedi2155 Model 3 has Arrived.

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    I've summarized my kWh and SOC% the entire it was at the service center. The ambient temperature varied from 40F to 70F during that period and the vehicle was mostly outside AFAIK (dust + bird poop and all). I think the vampire drain while not appealing or particularly great, its not TERRIBLE as long as things are working properly in my temperature zone.

    If anyone is experiencing more than 1-2% loss per day I'd seriously have it checked out.

    upload_2018-12-11_20-15-40.png

    That's what I've been told. I notice my car doesn't have to boot up compared to the loaner S which constantly have a boot up phase. I've NEVER had to wait for my Model 3 to "boot up".
     
  19. AlanSubie4Life

    AlanSubie4Life Efficiency Obsessed Member

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    #39 AlanSubie4Life, Dec 11, 2018
    Last edited: Dec 11, 2018
    Looks pretty typical. Confused by the negative losses in sleep mode (temperature increase maybe...seems like right order of magnitude...but not exactly cold and then warming up a lot on those days, so no idea really. Insolation warming the battery maybe).
     
  20. Daniel in SD

    Daniel in SD Well-Known Member

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    That explanation doesn't make much sense. My phone starts up way faster than my Model 3 and is connected to cellular, wifi, bluetooth and can take voice commands and has a standby power of less than 0.1Watts.
     
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