Why a full charge for 2020 PRIME is more than 2017 PRIME?

Discussion in 'Prime Plug-in Charging' started by Salamander_King, Aug 6, 2020.

  1. Salamander_King

    Salamander_King Senior Member

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    I traded in 2017 PRIME Premium to 2020 PRIME LE early this spring, shortly before the COVID-19 restriction started. Since the purchase, I have only driven ~1600 miles, and mostly driven by mix of HV and EV. For now, I only drive the car once a week or less and the car sit on idle for the rest of time. When I had 2017 PRIME, I was charging my car every night for following day commute of ~40 miles.

    Over the 2.5 years, I have charged the traction battery numerous times from zero to full, and the average kWh read by Kill-a-Watt meter on 120v OEM L1 EVSE was 6.53kWh/full charge. Currently, I am not charging my new 2020 PRIME 100% unless I know for sure I will be driving the car following day. For this reason, I have only charged the traction battery from zero to full 5 times in the last 5 months. But the average of kWh read by the same Kill-a-Watt meter on 120v OEM L1 EVSE is now 6.90kWh/full charge (hi 7.13kWh lo 6.72kWh).

    I have no idea why new PRIME is using more kWh to fill up? Does the battery that sit for a week or two unused require more kWh to recondition? Any other explanations?
     
    #1 Salamander_King, Aug 6, 2020
    Last edited: Aug 6, 2020
  2. bisco

    bisco cookie crumbler

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    toyota expanded the top and/or bottom limits? but that should give them more epa ev range
     
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  3. sam spade 2

    sam spade 2 Senior Member

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    Minor design changes over 3 years ?

    By design, the battery is only allowed to operate over the middle 70% or so of it's capacity:
    From a low of 15% to a high of 85% (example numbers only).
    Just a minor change in those charge/discharge levels would account for the relatively small difference that you are seeing.
    Or a small design change in the battery itself.

    OR....who knows ? And who REALLY cares ??
    There is no "reconditioning" involved.
     
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  4. Salamander_King

    Salamander_King Senior Member

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    I haven't see any change in real traction battery SOC level reported by Hybrid Assistant app on 2020 PRIME. SOC display 100% = 83% on HA and SOC display 0% = 14%-11% on HA. The bottom SOC level is somewhat variable depending on how much HV portion of the SOC has been depleted after EV range has been exhausted.
     
    #4 Salamander_King, Aug 6, 2020
    Last edited: Aug 6, 2020
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  5. digitalundertaker

    digitalundertaker New Member

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    Maybe the 2020 is using the cooling fans more.
     
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  6. MSantos

    MSantos EcoAccelerometry

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    Well, not sure this will help but here are my two cents:

    - My 2018 appears to still have the same range and it regularly slurps the same amount of energy at each event as it did on day 1. Driven in EV well over 95% of its lifetime but on the other hand, rarely experienced an SoC of 20% or less.
    - The 2020 appears to behave exactly the same way as far as usage, charging kWh and range goes. During the summer months, it matches the 2018 in terms of kwh/100km too where it easily gets 9 to 10 without effort.

    In summary, I cannot see any significant difference between the two even though I expected the 2020 to be lighter and thus more energy efficient. The charging and conditioning profile is also surprisingly identical between the two because each have their own EVSE and both are metered on total energy used per charge event.:rolleyes:

    cheers
     
    #6 MSantos, Aug 7, 2020
    Last edited: Aug 7, 2020
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  7. jerrymildred

    jerrymildred Senior Member

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    Seems plausible. Have you tried timing it, @Salamander_King? You have to have timing before to compare, of course.

    Or you could compare how many watts (or amps) it's drawing as it charges. Perhaps the new car is pulling slightly less current. If so, it would take longer to charge and therefore run the fans longer. Just guessing here.
     
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  8. Salamander_King

    Salamander_King Senior Member

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    That's exactly what I expected when I first got 2020 PRIME. For the first few full charges on my 2020 PRIME, I thought it maybe some coincidence, but after 5 full charges I have done, it seems my 2020 PRIME is using more kWh to fully charge the traction battery compared to my previous 2017 PRIME. Then again, there are people who reported less than 6.0 kWh to fully charge his PRIME, so I am thinking there maybe some variations among individual traction batteries. However, since I have only n=2 samples to compare, any number difference is statistically insignificant.
     
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  9. Salamander_King

    Salamander_King Senior Member

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    Yeah, plausible explanation. I never recorded time for a full charge nor the actual amp drawing for the 2017 PRIME, so no comparison can be made. At least, I am not seeing noticeable difference in EV ranges between the 2017 and the 2020. Then again with only 0.37kWh difference, even if there is actual difference in usable traction battery capacity, it will be ~1.85miles increase (at 5miles/kWh). This would be within a margin of error that I would not notice, especially now I am only driving once a week.
     
    #9 Salamander_King, Aug 7, 2020
    Last edited: Aug 7, 2020
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  10. Salamander_King

    Salamander_King Senior Member

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    Did another full charge from 0% EV range to 100% EV range last night. The temp was in 50s, and the car has not been driven over 12 hours before the start of charging. Thus no traction cooler would have kicked in. (I did not have the cooler sign up anyway.) This time a full charge was 6.88kWh in agreement with the 6.90 kWh average.
    HA reported my 0% SOC was 12.16% and 100% SOC is 82.75%.

    upload_2020-8-9_9-21-58.png
     
  11. john1701a

    john1701a Prius Guru

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    Has your EV range increased? There is nothing stopping Toyota from refining build/chemistry of the battery-pack and choosing not to submit the improvement. Have you removed the flooring to verify capacity is listed at 8.79 kWh still?
     
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  12. Salamander_King

    Salamander_King Senior Member

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    No obvious noticeable increase in EV range so far. But since I have not been driving everyday commuting like I use to, a direct comparison to my 2017 PRIME use case is difficult.
    upload_2020-8-9_9-43-58.png

    I have not removed flooring on my PRIME neither on the 2017 nor on the 2020. Where do I look for that information on the battery? Any photo?
     
  13. john1701a

    john1701a Prius Guru

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    Sorry, I don't have a photo handy. There is always a label on the casing. It's obvious. I remember seeing it when I took the back apart trying to figure out how to install the hitch without interfering with the sensor wiring. That's how I discovered it was really 8.79 kWh and not actually 8.8 kWh.
     
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