EV mode warm up

Discussion in 'Prime Fuel Economy & EV Range' started by AldoON, Jun 1, 2020.

  1. AldoON

    AldoON Member

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    Sure, in good conditions you can get the display to show values under 10 kWh/100km... But considering that the car is EPA rated at around 16, it seems like a bad choice to make the scale 0-10 kWh/100km.
     
  2. AldoON

    AldoON Member

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    Thanks for the reply :) Your statement that you observe a larger drop in range when battery is almost depleted vs when it is full is somewhat consistent with what I'm seeing.

    As a couple of others have mentioned, the very specific condition I'm looking for is:
    If you let the car sit overnight with low SOC (6%), do you observe a higher than normal decrease in battery within the first km of driving.

    Unfortunately I haven't had a chance to retry this condition. I have driven many times starting with a SOC above 50% and consistently observe up to a 3% battery drop in the first km of driving.

    Still planning to post an update when I get more useful results.
     
  3. Tideland Prius

    Tideland Prius Moderator of the North
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    I agree. The metric setup is useless - I can't use the Consumption Screen nor the instant FE because the choice of scale min/max values are poor.
     
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  4. jerrymildred

    jerrymildred Senior Member

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    Slightly off topic, but I also find that the resolution for the L/100km is woefully inadequate. When it says 0.6 L/100km, is that 0.55 or 0.64? It could be anywhere in that range between 367 and 427 miles per gallon, both of which are well above my maximum display of 199.9 mpg. I can guess more accurately by looking at the gas gauge. Won't know till I buy gas in a few months. What pin head dreamed up those limits? Thankfully, they fixed the mpg range for most drivers the next year but they haven't seen fit to update the programming in the 2017.
     
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  5. Tideland Prius

    Tideland Prius Moderator of the North
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    Yeah. It was fine when it's 8.5L/100km haha. I mean it's the same system used across all their vehicles so it has to also display 15-20L/100km for their Sequoias and Land Cruisers.

    But when we get down to the nitty gritty, an extra decimal point can be helpful.
     
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  6. AldoON

    AldoON Member

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    Managed to try trip today immediately after I got home from a long drive. Battery only decreased from 6% to 4% over the 1.0 km trip.

    Here is the direct comparison warm vs cold:

    upload_2020-6-18_21-25-47.png

    Why does this happen??!!?? o_O
     
  7. alinica2001

    alinica2001 Member

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    I don't know why this is happening but I do know I have a similar behavior on my car. I have 70k km on mine. How many miles/km does your have ?
    Regarding behavior, this can happen due to three reasons :
    1. Battery degradation.
    2. Trans oil viscosity is higher due to cold oil and therefore higher power consumption .
    3. some electric load which is happening during the "cold" initial phase of electric drive.

    Your car did the same straight from the beginning ( brand new ) or this behavior has developed in time ?
    If this has developed in time, then this is either no 1 or no 2.
    How many miles do you have with your transmission oil ? Mine was never changed...
     
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  8. AldoON

    AldoON Member

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    I'm also at 70k km. Never changed transmission oil as far as I know (bought car used).

    Interesting thought with the oil viscosity... Is be shocked if it has this much of an effect though! Also, I only see the big SOC drop when battery is almost drained (6% left) and car sits for several hours before being driven. If it was oil viscosity or any sort of friction loss I would expect to see the big decrease in SOC even when battery is at a higher SOC and car is "cold" but this is not the case.

    I guess same argument applies for an electric load when the car is cold... Would expect to see the effects of this load regardless of initial SOC.

    I'm starting to think along the lines of battery chemistry and how the car measures SOC. I believe battery voltage change is non linear and drops much more rapidly when the battery is getting close to empty... Maybe it had something to do with that?
     
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  9. alinica2001

    alinica2001 Member

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    How many km/miles can you drive with a fully charged battery until ICE will kick in ? I would like to see your best numbers ( not going downhill but in almost ideal conditions :) ). I can do 38.4 miles ( around 62 km ) in almost ideal conditions ( average speed around 36 mph and no A/C )
     
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  10. bisco

    bisco cookie crumbler

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    there's a thread for that (y)
     
  11. alinica2001

    alinica2001 Member

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    do you have a link ? Thx.
     
  12. Salamander_King

    Salamander_King Senior Member

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    #52 Salamander_King, Jun 23, 2020
    Last edited: Jun 23, 2020
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  13. AldoON

    AldoON Member

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    Interesting update on this issue. It stopped happening after I replaced my 12V battery.

    Either something in the memory got reset when I unplugged the battery, or perhaps my dying 12v was depleating overnight and the decrease in range was caused by recharging the 12V when starting the car the next day.

    I'm thinking the second option... But I couldn't explain why it only happened when I had very little SOC remaining.
     
  14. vvillovv

    vvillovv Senior Member

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    Yes! I can confirm the behavior too. I have wanted to start a tread about it for a couple of years, though lacked comprehension of the issue enough that any post I made about it would be too far out of the realm of Primes normal behavior for others here to be very interested in the subject at all.

    I do a lot of EV range testing and have experienced the issue whenever I'm at low EV range and shut the car off, than restart the car again.

    So far I'm convinced the issue is some kind of reset when shutting the car off. I've even thought I'd like to find where the EV range limit is for this reset issue to easily show up to any Prime driver paying close enough attention to how the car behaves.

    It's complicated by starting EV range as opposed to expectations of actual EV range for any two of more dirvers. ie: If a driver is expecting to the beat the Estimate or Not quite make the Estimate or be well below the Estimated EV range.

    In short, if a driver knows about how far a set amount of EV range should make their car travel, than shuts the car off with less than 20% EV range left. The next time the car is started, the EV range gets used up at a much faster rate than if the car had not be shut off and the driver just continued the trip.

    It happened to me just a week or two ago, again.

    I believe the car has a shut off reset that causes this behavior.
    But, I wouldn't want to argue about the details of just how observable it might be to other Prime drivers.
     
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  15. jerrymildred

    jerrymildred Senior Member

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    If you look at the correct ECO history page on the MID, it shows a bar for each mile driven for the past 15 miles. Each bar represents the miles/kWh for that mile. You'll notice that the first mile is alway way, way low. There's always a big hit just getting going.

    So, if you take a drive that uses 80% of the battery's capacity and then stop, you took that hit early on and then drove a bunch more miles at normal miles/kWh which helped it average out. Being spread out over a longer distance, the initial bad efficiency has less impact on the average. Then you stop and shut it off. Then you drive off the last 20% of charge. That "getting started penalty" comes into play again but it's only spread out over a short distance so it has far more impact on that trips average miles/kWh.
     
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  16. vvillovv

    vvillovv Senior Member

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    Again, there's a lot of depends on initial "get started scenarios". ie; speed, acceleration, elevation, and probably others. The getting stated hit - if I understand your description correctly, which is virtually-always in dispute as I read others posts here, may be that way always for you, but may not always fit in other drivers trip scenarios. I did mention this issue is beyond what most Prime drivers will notice under normal driving scenarios.
     
  17. jerrymildred

    jerrymildred Senior Member

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    If the trip starts out downhill, you won't take that startup hit. Otherwise you'd have to show me another way. There's one trip I make regularly that is downhill for a ways but not steep and the first mile is close to the trip average. Physics is physics.
     
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  18. vvillovv

    vvillovv Senior Member

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    Like I said in my first post to this thread, I wouldn't want to argue the details of how observable the issue is to other Prime drivers. That includes you Jerry. But here I am defending an observation made my another Prime owner, that I've also noticed.

    But since you are relying on Physics to make your point, that from your experience, the issue is nothing but a startup hit, either from a low SOC state or a full SOC state, it would be nice to know your estimate of the percentage of EV range that is lost from such a start up hit at the beginning of a trip.

    Extra points for any other aspects of the startup hit might be at play when the pack is full and warm. It's just physics and battery discharge behavior, right.
     
  19. AldoON

    AldoON Member

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    Vvillovvv, was the hit you were seeing on the order of more than 6% battery charge drop within the first km of driving?

    That's what was happening with me. Strange thing is it stopped happening after I installed a new 12V battery...
     
  20. m8547

    m8547 Senior Member

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    I don't think it's a simple startup hit. More like the SOC display trying to maintain continuity when in the background it's estimate of the SOC is changing.

    I don't think I've seen a "startup hit" from a full charge. In fact there's almost an startup bonus. I think it might charge to 101-102% based on the SOC shown on Hybrid Assistant (which might go to 85-87%) vs what's shown on the car (which will never be more than 100%).

    From a partial remaining charge, the startup hit could be from a temperature change in the battery while it was resting, or maybe just a refined estimate of SOC. The car will almost never show a different SOC from when you park to when you start driving again, so the SOC display has to catch up to what the SOC actually is in the first few minutes of driving.

    A change from resetting the 12V battery is strange, but maybe there is a software explanation. For example maybe the car uses a model of the battery, and resetting the battery makes it relearn that model. For people seeing a startup penalty, the car could be making an excessively conservative assumption about the remaining SOC after the battery has rested for a while. It will act like there's less charge in the battery, and it adjusts the SOC display to catch up. It will even "run out" of range exactly when it thinks it should. But if it's actually wrong, it will even out next time you charge the battery, because it will need to out less energy into the battery before it's full (less than if you drove the full range on the first trip, instead of parking and breaking it up into two trips)

    Anyway, that's all speculation, and there may be no way to know for sure without asking an engineer from Toyota.

    I have observed a startup hit sometimes, usually when I park with relatively low SOC (maybe 10% or less) and leave the car overnight. I have also rarely observed the SOC increase, sometimes if I park after using up the EV range or maybe with 1-3% left, I might in rare cases have a little more range the next day.
     
    #60 m8547, Mar 2, 2021
    Last edited: Mar 2, 2021
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