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Low Battery Supercharging - 0 Kw and 90 minute charge time

Discussion in 'Model X: Battery & Charging' started by LovelyCarrot, Dec 6, 2016.

  1. LovelyCarrot

    LovelyCarrot Member

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    Verified this with Tech Support this weekend, I ended up at a Supercharger with about 3% battery in my 75D Model X. Plugged in and the screen showed 0 Kw, no miles charged, and a 90 minute charge time. The energy showed brief runs to 6Kw and back down to 0. Per tech support this is expected behavior, at low battery levels the Supercharger must trickle charge for 30-60 minutes before "opening up". For me it was about 45 minutes showing 0 miles charged, then suddenly it kicked in and ran at full rate. It did come in almost exactly as stated on screen at 90 minutes.

    I've found that the in car planner will happily put you to 2-4% at the next Supercharger when planning trips, so it's worth giving yourself the extra time at the previous charger so as not to find yourself with a 60-90 minute charge time instead of 20ish.
     
    • Informative x 2
  2. bushburner

    bushburner Member

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    i guess i shouldn't go below 10% on long trips if I don't want to spend long at a supercharger.
     
  3. ecarfan

    ecarfan Well-Known Member

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    Glad you were able to charge. I will do whatever it takes to avoid arriving at a Supercharger with less than 10%. I like to have a safety margin in case something unexpected happens. My spouse prefers a minimum of 20%. :)

    By the way, what was the air temperature when you plugged in at 3%? I assume it was fairly cool.
     
    • Like x 1
  4. aesculus

    aesculus Still Trying to Figure this All Out

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    I have run it down to 7% and never saw this. Anyone go lower before the effect kicked in?
     
  5. mspisars

    mspisars Member

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    That's kinda crappy... not recommended to charge past 90% unless on a trip. Based in this data, its impractical to go below 10% (maybe below 7%) when on trips... or charge past 90% because you are spending a lot of time charging.
    :(
     
  6. TexasEV

    TexasEV Well-Known Member

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    You shouldn't plan to go below 10% anyway, because too many things can happen that can cause you to use more energy than panned. That's a 20-28 mile rated range buffer, depending on your model, or the equivalent of one gallon of gas in an ICE.
     
  7. CSFTN

    CSFTN Member

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    Not crappy, that's always been the advice ... change to 90% or less unless you are about to take a trip, try not to go below 10% if you can help it. However, following these rules makes only a minor difference, under most circumstances.

    And on a trip you can charge to ~ 95% pretty quickly .. it only really slows down above that level. It doesn't REAALY slow until 98%. I've driven 1000 miles round trip and it really wasn't bad. My wife and kids were even in the car; she hated the idea but was absolutely fine with the actual trip.
     
  8. TacC

    TacC Member

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    Went down to 5% with no major issues. I felt that the charge started off a little slow; however, this was in San Mateo and all stalls were full so I just chalked it up to not having priority.
     
  9. mspisars

    mspisars Member

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    I think you missed the point.

    It is crappy. Just because it has "always" been the advice, does not make it "not crappy".
    I have put almost 50k on my Leaf and never limited my charge below 100% (and there was no advice to do so - and no noticeable battery degradation).
    With my X, the top 10% is recommended for trips only. MCU makes sure you are aware of this recommendation anytime you want to adjust the charging limit.
    With the OP's post it seems the bottom few % are also reserved for special situations.

    OP I am curious if this was the pack temperature or the low SOC of the battery that was the main contributor to the slow .
    Do you have a log (teslalog, remote tesla, etc) of this charging session?
     
  10. vjlvjl

    vjlvjl Bluebird

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    I have, on occasion, gone down to 4-6% SOC, and not have any issues superchargung. Temp between 40-85F on these occasions.
     
  11. mblanshard

    mblanshard Member

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    I charged on a trip over Thanksgiving week in Strathsburg, PA at 2:30am and it was ~9 degrees F. I arrived at 3% battery and the charge took almost 2 hours to get us to the next stop. It was originally supposed to be a 1 hour stop. I think it was a temperature issue because before we could charge it stated it was heating up the battery and turned off the cabin heat on us :)
     
  12. Marc_GA

    Marc_GA Member

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    I have never heard of this and it doesn't pan out with personal experience or any of the supercharging spreadsheets that exist. Search 'tesla supercharging spreadsheet' on google and check the first couple.

    I routinely arrive at 4% or less (many times with 3 miles left) a few times a month and have never seen this myself. It is true that once you plug in it will do 0Kw, few Kw, 0 Kw and then ramp up but it is typically in the 100+ kW range by the end of one minute after plugging in.

    I do this in 20-95F temperatures.
     
    • Like x 1
  13. TexasEV

    TexasEV Well-Known Member

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    With your Leaf you probably needed to use the top 10% if you want to make it through the day around town :) Also when Nissan dropped the 80% charge setting for daily use, the advertised range of the Leaf went up by 10%-- because the EPA used to average the range of the two settings. It was a marketing thing on their part. That's why Tesla dropped the fixed daily setting of 92% and went with the slider in a firmware update two or three years ago, so it's EPA range wouldn't get averaged down.

    With the range of a S or X, why would you want to use the top 10% except when you're going on a trip and need that range? If you can plug in every night as recommended, 90% of 200+ miles is more than enough for routine daily use. If it isn't, consider it a "trip".
    Also it doesn't remind you any time you want to adjust the charging limit. It gives a reminder if the car remains set at 100% charge for three days-- in case you have forgotten to set it back down after a trip.
     
  14. goneskiian

    goneskiian Active Member

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    Hmmm, the one time I arrived at SpC with about 2 miles left I don't recall seeing this. I will admit to not looking at my app while I went to get lunch but I certainly didn't sit there for an hour before it was dumping massive amounts of electrons into the battery. It wasn't exactly a cold day though (probably in the 60's).
     
  15. rypalmer

    rypalmer Member

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    Are you sure it wasn't warming up your battery to prepare it to charge? I've never seen this either, and I routinely push the low end limits of my battery.
     
  16. gabeincal

    gabeincal Enjoying Napa life the electric way

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    I was at 2% (rem. miles 7) with a P90D the other day and didn't see anything like this. Charged as normal.
     
  17. balefire

    balefire Member

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    Never happened to me either. When Tesla set the cross country record, they intentionally arrived with the battery nearly empty since it charges faster. ... Who else has experienced this?
     
  18. hiroshiy

    hiroshiy Supporting Member

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    Is this something related to newer battery chemistry? I'm worried as I have X P100D on order and my Classic P85 supercharges fine from 0 rated range or 1 miles of rated range.
     
  19. pdxrajiv

    pdxrajiv Member

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    The quoted post above and others appear to point to a combination of initial low-charge and low battery temperature leading to slow initial charging rates - explained by the need to heat up the battery before it can be fast-charged.

    Thinking about this a bit: This is an engineering optimization problem. Everything in/on the car is intended to be fed from the battery. If the battery has a low-initial charge, you can't draw much from it (to heat the battery), so you must build up the battery charge at a slow-rate until it has enough so you can safely draw enough to heat the battery, to charge the battery at a fast rate.
    If the battery-heating circuits were designed to draw power directly from an outside source (SC or AC charger) in addition to the connection from the battery, this situation could be improved drastically.
    Hey, maybe I should file a design patent - Method and Apparatus to Fast Charge a Car Battery with Low-Initial Charge at Low Battery Temperature. :)

    FWIW, I have charged my MS battery at the normal rate at home, starting from 0 RM. with ambient temp in the 60s.
    Same experience at SCs with temps as low as 40F and 4 RM.
     
    • Informative x 1
  20. Saghost

    Saghost Active Member

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    What was the climate like?

    Did you plug in immediately on arrival?

    If I remember right, starting at like 8 or 10% it stops heating the battery to conserve power...

    I've seen some surprisingly slow rates when the pack is cold, but never simply from being low (but I haven't been down quite that far yet.)
     
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