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Sudden Increase in Consumption Rate

Discussion in 'Model X' started by Ski Krazy, Nov 21, 2017.

  1. Ski Krazy

    Ski Krazy Member

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    Hey Everyone,

    In trying to keep my thoughts and your read organized, I broke it down into sections. Thanks for your help!

    BEFORE

    I got my brand new Model X 100D in early September. Except for minor trim issues that I decided to leave be, it was the car my wife and I dreamed of.

    Over the last couple of months, we've done a couple road trips to the Seattle and Portland areas, but otherwise most of our driving has been like any other -- inner city. We live a little bit outside Vancouver so we get more highway driving than usual, but in that time we've averaged roughly 225 Wh/Km over some 7000 Kms (the two road trips added to that quite a bit).

    To give you a sense of our driving styles, I tend to be the more consumption conscious one out of us two but even then I typically just enjoy the ride. Our range mode is off; we had it connected to the app for a while until the vampire drain became too much; and usually drive with the climate control on.

    As for Vancouver weather and terrain, outside of a week in late October-ish that was in the -1 to -8 range, while it's gradually been getting colder, it's usually been in the 3 to 12 range (Celsius). Vancouver can be hilly at times, but our weekly commutes stay relatively flat. Even if we do run into hills, it's nothing that would seriously affect our range.

    Finally, we park the car in our garage to charge overnight and it's had the .34 software update since delivery, until...

    AFTER

    Two weeks ago we got the .42 software update. I identified the above to point out that all of our driving habits, commutes, weather, etc. has been the same even after the update.

    Since then, our steady average consumption rate quickly jumped seemingly overnight from 225 Wh/Km to 280, driving somewhat conservatively. If I try my best, I can hit 260. Similarly, if I don't pay attention to consumption then I'll hover around 300. Before, I'd be able to hit 190, but no more.

    Additionally, immediately upon starting a drive, the current trip average starts around 1,000 Wh/Km and takes quite a few kms to get down to 300. One time, when we had 6 passengers, we got in the car and turned on all of the seat heaters and saw a steady consumption rate of 1,800! Remember that this is above freezing weather. I mean, I understand it takes some extra battery but this is insane.

    What's even weirder is that I had one short drive in the middle of this sudden jump in consumption rate where the immediately upon starting to drive, the consumption was in the high 100s and quickly fell to just over 100 for the 5 minute drive. While it would've been great had that lasted, how does that make sense?! Well, the next time I drove the car, it was back to it's high usage ways.

    I also got winter tires installed a week ago but that was already after the fact and it had no noticeable effect on the range and consumption either way.

    CAUSES

    So with that said laid out, what could possibly be the cause? Better yet, have any of you experienced something similar?

    I called Tesla and they first suggested it was the colder weather, the battery taking time to warm up, etc. Firstly, it's not even freezing and yet it's supposed to be reasonable for me to lose 20 to 35% of my battery range? Also, the one cold period we had below freezing the Model X was perfectly fine and showed no sign of any issues. Of course they assumed I parked outside but I didn't.

    They then said that it's common to experience slight battery degradation after one month. Well, again, I understand a slight degradation, even 5%, but these numbers are ridiculous. Plus, it's been 2 months.

    They then asked me some questions to help with troubleshooting, but they called me back tonight and said the engineer found that the car had no noticeable problems. So I have an appointment set for 2 weeks from now that I already had booked for a wheel alignment, so I have added this issue to their plate and hopefully they can find something then.

    I thought I'd share my story here in the meantime hoping the community can help solve it or share if they've had similar situations, and if so, what you did to fix it. Like I said, from my recollection, my average consumption rate changed within a day right around when I got the new software update, so that's the only thing I can possibly attribute it to. Nothing else has changed from before the problem to after.

    Thanks for reading!
     
  2. avirtuos

    avirtuos Member

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    Sounds like cold weather affects to be honest. Did you notice limited regen or power indicators at all? Have you been using the heater more?
     
  3. jdw

    jdw Supporting Member

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    Montreal, Canada
    #3 jdw, Nov 21, 2017
    Last edited: Nov 21, 2017
    Sounds mostly normal , at least for the 2-3-4 degree weather. When you see usage over 3-400wh/km (and up to 1200-1800wh/km) it is usually due to the battery heater turning on and the car heater and seats add to that (6kW+6kW+2kW+ motors). It usually reduces fairly quickly as you drive. You can minimise this by using charging timed to finish about the time you want to leave to allow charging to warm the battery and/or by engaging range mode. Range mode reduces or prevents the battery heater from coming on as well as reducing power to the heater.

    Range mode is also useful if you have a sequence of short drives in cold weather, as the drive/park/drive/park cycle can really eat up a lot of charge by heating the battery only to have it cool off again.

    I find parking for 8 hours in temperatures around 12-15C will result in slightly limited regen. 5-10C will usually substantially limit regen and cause the battery heater to come on for a while when starting to drive. Below zero, and the battery heater will draw *a lot* of power for about 5 minutes or so. Parking outside all day at -25C, I've hit 2200wh/km and had acceleration seriously /dangerously limited for 10 minutes or so, along with zero regen.

    Recommended reading:

    Cold Weather Driving
     
    • Informative x 2
  4. AlgaeHater

    AlgaeHater Member

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    Location:
    Bellevue, WA
    I posted a very similar problem. After I uncorked the car, I went from low to mid 300 Wh/M to over 400. Even driving at 60-70 mph, I cannot go below 370. The weather has gotten a bit cooler in the PNW, but it's not that cold yet at around 50 degrees.
     
    • Informative x 2
  5. Ski Krazy

    Ski Krazy Member

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    Vancouver, BC
    I noticed limited regen once within the first month (way before any of this started happening), but it went away shortly thereafter and didn't affect my long distance/term consumption rate.

    Even taking the extra energy it needs to heat up the battery into account, it still doesn't fall back down anywhere close to where it was before even over longer distances when I drive 50+ kms. While my wife drives many short distances, I tend to get the longer ones and I haven't seen any improvement in consumption rate with increased driving distance. I get to the 260-280 range within a few kms but can't get any lower than that unless I'm on a fairly long down hill road.

    Plus, over the last couple weeks the weather's been hovering around 10 degrees, give or take a couple, during the day and it makes no difference. Whether I drive in 2 degree weather or 12, I have the same issue so I'm very inclined to say it's not the cold weather. Like I said previously, the car's been in colder weather than what it's been like the last couple weeks when the consumption was normal and it stayed that way for the next month or so, so again, my findings just don't support that conclusion.

    Thanks for the tips on range mode though.

    As for charging, living in a townhouse, it's been a pain trying to get my outlet upgrade installed. While I'm finally a few days from getting it done, I've been on trickle charge this whole time, so the battery is always charging when I'm about to leave, so it should always be warm in the mornings.
     
  6. shokunin

    shokunin P85 & M3

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    Check your tire pressure to see if it's dipped due to the colder temperatures. Wet and damp roads, heater usage, denser air, can reduce efficiency.
     
    • Helpful x 1
  7. BerTX

    BerTX Supporting Member

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    Rain, or wet roads, can make a 5% drop in range, so that may be a factor in the weather change. Also, it doesn't take freezing temperatures to make a difference -- the range will drop markedly as temperatures drop from about 25º C.

    The heater makes a big difference. It is resistance heat, so very inefficient. Remember, the car was designed in California for Californians, so heating efficiency is not a priority.
     
    • Like x 1
  8. vandacca

    vandacca ReActive Member

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    I recall reading that a recent OTA update changed the way range was calculated. It shouldn't affects the energy graph, but I guess it's possible? And @shokunin had a good idea with tire pressure as it can definitely increase consumption.

    Also, if you recently got your vehicle uncorked that may increase consumption because cork is a good insulating material.

    Unless you start seeing other changes or symptoms (eg battery drain, huge vampire losses, weird noises, etc.) I wouldn't stress over it too much. It's entirely possible that nothing has changed, except the algorithms and it's just reporting more accurately now.
     
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  9. timx

    timx Member

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    Location:
    Iowa
    This will be my first winter with the X, and I've also noticed increased battery consumption in the past few weeks while it has gotten colder around the freezing point. We also have a Ford Fusion plug-in, that gets about 25 electric miles in summer, and about 12 miles in winter -- and that's without using the heater or defroster -- turning that on reduces it to about 8 miles. So far the range reduction in the X seems somewhat consistent with other batteries, though seems to be mitigated somewhat with the battery heater.
     
  10. qadaemon

    qadaemon Member

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    Here's some anecdotal data on my 90D. 40-something thousand miles on the car, probably 30-something shown on TeslaFi. How well does it match yours? I believe the rated range for my model is 332 wh/mi. In the summer I'm usually at ~400 wh/mi, in the winter roughly 470. X 90 D Temp/Efficiency graph
     
  11. chilman408

    chilman408 Member

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    It is due to Winter weather.

    Here in CA with my 75D uncorked, I'm actually getting very slightly LOWER consumption on my daily commute ~5%. I have a 90 mile daily commute that is the same traffic everyday (sbay to SF).
     
  12. aesculus

    aesculus Still Trying to Figure This All Out

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    I got lazy last night and came in at 16% and did not plug in. In the AM (about 14 hours later) with an outside temp of 45F, when I started the car, it said it was 9%. My normal vampire, drain confirmed earlier this week, is about 1% a day.
     
  13. jdw

    jdw Supporting Member

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    As to usage, I can say that in the summer, I usually use 10% of my rated charge to drive to work and back (90 to 79-80%). In the fall, that goes to 15% (90-75%) and in winter, up to 20 or even 25% (90-65-70%)
     
  14. mknox

    mknox Well-Known Member

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    Going into my 5th winter with my Model S. I can say with a fair degree of certainty you're just seeing the effect of the colder weather.

    Funny how people who buy their car in the middle of winter never report "sudden decreases in consumption" when the weather turns warmer ;)
     
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  15. AlgaeHater

    AlgaeHater Member

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    Ok so I ran a test and drove to work with the heater completely turned off. Result - 297 Wh/mile. Had no idea that the heater consumed so much energy even when the temperature differential was only 15 degrees.
     
    • Like x 1
  16. jdw

    jdw Supporting Member

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    Parked outside for about 8 hours today at 0C ... car hit 950wh/km for 4 minutes driving at 100km/h, then dropped to 450 for another 3-4 minutes then worked its way down to 250 , based on "last 10km" tab on the energy graph. Average for the entire 20km trip was 220wh/km. Heater on, set to 22C. and range mode off. For reference ...
     
  17. chadcristi

    chadcristi Member

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    The cabin air heater definitely uses a ton of electricity! The numbers you’re seeing are undoubtedly related to cold weather. I also agree with the effect the lower temps have on tire pressure which also results in higher energy consumption. The seat (and steering wheel) heaters use much less power if you don’t mind having a cold face. Tesla recommends using the seat heaters instead of the cabin heat to improve cold weather efficiency.
     
  18. hiroshiy

    hiroshiy Supporting Member

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    As you might object I believe it's the battery heater kicking in as it is automatically turned on around 8 degrees Celsius and people usually don't feel very cold if outside temp drops below 8C. You can check with TeslaFi whether the battery heater is tuned on or not, by customizing the template for a drive. If it's on, it consumes up to 6kW of power so that is significant.

    Or you could test by turning on Range Mode, as it won't turn on the battery heater well under freezing. Note that
    After you drive and park, the battery is warm for hours.
    120V charging doesn't heat your battery. It's just not enough power.
     
    • Informative x 2
  19. Barklikeadog

    Barklikeadog Banned

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    This type of thing is common in the auto industry. ICE vehicles for example... the gas tanks shrink by a gallon per year.
     
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  20. scottf200

    scottf200 Active Member

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    Some of the below overlap to BEVs/PHEVs...

    gas/ICE cars: 9 reasons your winter "fuel" economy bites

    9 reasons why your winter fuel economy bites! - MetroMPG.com


    1. More idling
    This should be a no-brainer, yet parked idling cars are a common sight in cold weather. Resist the temptation to idle your car to warm it up. An idling engine gets 0 mpg. Consider also that idling the engine does nothing to warm up the tires and drivetrain.

    Even in the coldest weather, you can begin driving after 30 seconds from a cold start - keep speeds low/moderate and use gentle acceleration until the temperature gauge starts to climb (source).

    2. Low tire pressure
    Of course you're smart enough to keep up your tire pressure as the temperature drops, right? A 10-degree (F) change in ambient temperature equates to a 1 psi change in tire pressure (source). Fuel economy declines 0.4 percent for every 1 psi drop (source).

    3. Increased rolling resistance
    Even if you're completely attentive to proper tire pressure, cold ambient temperatures will still cause your tires to return worse mileage. That's because a tire's shape isn't completely round - the sidewall bulges out at the bottom, and where the tread meets the road the small contact patch is actually flat. As the tire rotates, it constantly deforms to this shape, and this deformation requires more energy when the rubber is cold and hard. Rolling resistance at 0 degrees F is 20% greater than at 80 degrees (source 1, source 2).

    4. Crappy road conditions
    It's increased rolling resistance of another kind: driving through slush and snow. And then there's its wasteful polar (no pun intended) opposite: no friction at all! (A.K.A. wheelspin on ice.)

    5. Lower average engine temperature
    In the winter, an engine takes longer to reach operating temperature and cools off faster when shut off. Since the engine management system orders up a richer mixture when cold (proportionately more fuel in the air/fuel combination), more fuel is being burned overall.

    A block heater can offset this problem (improving fuel economy by 10% in sub-zero conditions - source), as can garage parking, and combining trips (to minimize the number of cold/hot cycles).

    Also related...

    6. Higher average lubricant viscosity
    Engine oil thickens as it cools. So does transmission and differential fluids and even bearing grease. Significantly more energy is needed to overcome the added drag these cold lubricants cause.

    Using synthetic fluids can address this problem, since their viscosity changes less at extreme temperatures than traditional mineral fluids.

    7. Weaker gasoline
    Gasoline doesn't vaporize readily at very cold temperatures. So oil companies formulate fuel differently for cold-weather markets in the winter. Unfortunately, the changes that provide better cold vaporization characteristics also result in less available energy for combustion. You won't get as far on a liter of winter gas as you will on a liter of summer gas. (Source.)

    8. Higher electrical loads
    In colder temps, you use electrical accessories more often:

    - lights (in higher lattitudes it's darker in the winter)
    - rear window defroster (because it's easier than using the ice scraper, right?)
    - heater blower motor (I don't have a/c, so this isn't balanced out during warm conditions); heated seats/mirrors
    - windshield washer pump (because it's easier than using the ice scraper, right? And for frequently cleaning off dirty road spray.)

    9. More aerodynamic drag
    No, I'm not referring to the layer of snow you're too lazy to brush off the top of the car (though that would hurt mpg too).

    A vehicle’s aerodynamic drag is proportional to air density, and the density increases as temperature drops. For every 10 degree F drop in temperature, aerodynamic drag increases by 2% (source).

    I would think "Higher average lubricant viscosity" is one of the biggest. Think about grease/lub on wheel bearings/axles/etc.
     
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