Puzzling 2014 Prius Plug-In Estimated EV Range Decline

Discussion in 'Gen 1 Prius Plug-in 2012-2015' started by Alex V, May 21, 2019.

  1. Alex V

    Alex V Junior Member

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    I purchased this vehicle used and have owned it for 2+ years and put 34K miles on it since (starting at 29.4K and now at 63.8K). Over last 2 months, estimated EV range started to deteriorate well below the range it had previously fluctuated within (11.8 to 14.4 miles). The last couple of weeks, I have lost 1/10th of a mile in range per charge and I am now at 10.2 miles. And yes, before all the flames, I am well aware that driving style, tire pressures, routes, etc. all factor in determining that estimate. I am driving the same daily route with no recent tire change, load variation, speed, etc., i.e. conditions unchanged. Even more puzzling is the one-way route actually measures 11.8 miles, but my EV range drops 9.6 to 9.8 miles when I now drive it. In other words, the vehicle appears to be under-estimating distance. Any useful suggestions?
     
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  2. bisco

    bisco cookie crumbler

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    welcome!
    how many actual ev miles are you getting?

    do you drive hv at all?

    are you using more a/c?
     
  3. QuantumFireball

    QuantumFireball Active Member

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    Turning on the HVAC will reduce the estimated range by about 10% regardless of actual power consumption. Did you have the climate control turned off two months ago, but have since started it using it?

    Also, check the rear brake caliper slide pins are moving freely.
     
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  4. Alex V

    Alex V Junior Member

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    Bisco - I haven't measured beyond the 11.8 mile one-way commute that depletes the EV range by 9.6 to 9.8 (call it 9.7), but that is not far from total depletion (estimated EV range now down to 10.0). So, that would work out to 12.4 actual miles of estimated EV range. I don't know if that is what you were asking. I always start in EV mode and when it depletes, car switches over to HV mode for the balance of the trip/day, but lately I haven't gone on excessively long trips although I definitely log miles in HV mode after depletion. A/C usage is not a player as we have had unusually mild weather this spring.

    RaytheEagle - I made sure not the HVAC was not on to avoid clouding the data. However, I do like the brake caliper suggestion. Will investigate.

    Thanks to both!

    Any benefit to resetting the estimator to see how rapid the estimate declines and where it restarts or settles? Has anyone tried the white wire disconnect method described in

    ?

    Does it reset everything else as well?
     
    #4 Alex V, May 24, 2019
    Last edited: May 24, 2019
  5. john1701a

    john1701a Prius Guru

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    Why does ESTIMATE matter? That calculated value doesn't really tell you anything useful.

    Why not measure ACTUAL instead? You can monitor both miles & percentage to get an understanding of what the battery is really experiencing.
     
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  6. Alex V

    Alex V Junior Member

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    John1701a - it doesn't matter UNLESS it is indicating an issue. The fact that it is all of a sudden behaving differently is the concern, not the actual number displayed.
     
  7. bisco

    bisco cookie crumbler

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    i'm still not quite clear. are you saying your actual range hasn't changed, but the estimate has gone down?

    sorry for my feeble brain.:)
     
  8. Alex V

    Alex V Junior Member

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    Unfortunately, I can't tell because I never had a need to determine if the actual range was higher than the estimate until this strange decline started.
     
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  9. john1701a

    john1701a Prius Guru

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    Estimates won't ever indicate an issue.

    Seeing sudden behavior change is quite normal. Some owners, like myself, see it each time the cold season arrives & departs.
     
  10. bisco

    bisco cookie crumbler

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    if it is any help at all, i'm getting around 13 miles actual, around town, in 60-70 degree weather, with no hvac.
     
  11. Alex V

    Alex V Junior Member

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    Another strange indication today... I had to unplug before full charge achieved to go run an errand. Started the vehicle and the initial indication was 10.8 EV miles available, which immediately dropped within a couple of seconds to 9.5 EV miles, with the car still stationary. Bizarre!!! Battery issue? BTW, I had checked for possible issues (e.g. stuck/dragging rear brake) and did not find any issues...
     
  12. QuantumFireball

    QuantumFireball Active Member

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    Did you turn on the climate control between the two readings? Because it will do exactly that.
     
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  13. bisco

    bisco cookie crumbler

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    all it takes is the fan on to reduce the 'estimate'. this is too let you know that running the hvac may result in less ev miles.
    it is too simplistic, seeing that hvac uses vastly different amounts of energy based on settings, ambient temp and humidity, but it is all we have.
     
  14. Alex V

    Alex V Junior Member

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    Thanks, QF and B. I did not manually turn on anything but the A/C was already on Auto, so it may have kicked in explaining that drop.
     
  15. bisco

    bisco cookie crumbler

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    i never use auto, so i'm not sure. does the fan ever shut off in auto?
     
  16. jb in NE

    jb in NE Senior Member

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    I would not put too much stock on the guess that the display provides. What matters is the range you can actually achieve, not what it predicts. I find that the GOM on the Prime doesn't usually match the range I actually achieve. If you were getting reduced EV range under similar conditions, then I would start figuring out why.
     
  17. QuantumFireball

    QuantumFireball Active Member

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    No, it's always on. I nearly always use auto as it adjusts fan speed and direction appropriately for the set temperature, I think it's quite good.
     
  18. bisco

    bisco cookie crumbler

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    then, you shouldn't see a drop in the estimate. when you turn the car on, the estimate should already be reduced.
    to confirm: turn car on, read estimate, shut hvac off, read estimate again
     
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