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2023 Prius Prime: Charging Mode Rate

Discussion in 'Gen 5 Prius Technical Discussion' started by tovli, Aug 14, 2023.

  1. tovli

    tovli 2023 Prius Prime replaced 09 Prius

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    Today I jumped into HV Charging Mode today at SOC 70% while driving steady at 40mph. 275v at 11A which is roughly 3 kW. When I slowed to a stop the charge rate briefly went as high as 40A, then returned to roughly 11A. When I accelerated from the stop, the charge rate went up again around 40-50A during the initial acceleration then returned to roughly 11A.

    Update: removed all WAG, just answered the question originally posed.
     
    #1 tovli, Aug 14, 2023
    Last edited: Aug 15, 2023
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  2. KMO

    KMO Senior Member

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    I think that's a bit of a leap. I suspect keeping the ICE in an efficient rpm/load level is a big factor. In normal cruise it won't want to push the ICE too far away from the efficiency it would achieve normally for the requested wheel output.

    As you saw, when accelerating, it was happy to push all the way up to 11kW, presumably because it was already resigned to have a high-revving engine.

    You should retest with other steady speeds. It may be coincidental that efficiency at 40mph is roughly 3kW.

    And quite possibly it may be that 3kW is actually the minimum. They don't want it to charge slower than a wall charge.

    The rule may be something like "min 3kW, max 11kW, do not reduce engine efficiency by more than X".
     
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  3. vvillovv

    vvillovv Senior Member

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    charge mode ( --- to 80% SOC) can also be compared to wall charge (--- to 80%) time. ie: find the speed where charge mode takes the least amount of time to charge the traction pack from (--- to 80% SOC) than time the same charge from the EVSE, either or both 120 , 240 volts. The Gen 4 Prime averages around 8 amps close to 9 amps at 240 volts Level 2 (8.8 or 8.9 amps at the very beginning) tapering to low 8. amps for 1,5 hours, than another half hour at much lower amps, 2 or 3 maybe, I'll have to watch more closely next time.
    So if it takes charge mode around half and hour to charge from (--- to 80%) that is quite a bit more than 3.3 kWh in the Gen 4.
     
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  4. tovli

    tovli 2023 Prius Prime replaced 09 Prius

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    No, I should not. I was trying to answer a non-Gen 5 owner’s poorly posed, off thread track, question with a 2 minute jump into charging mode. I was not testing a feature I have no use for, nor designing one or more tests to characterize the feature.

    I got carried away beyond the single point where I have zero experience. I have revised my answer to limit my obvious ignorance.
     
    #4 tovli, Aug 15, 2023
    Last edited: Aug 15, 2023
  5. Louis19

    Louis19 Active Member

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    I agree that charge mode is quite a bit more than 3.3 KW. Charge mode is a DC to DC charging operation. It's source is MG1 rated a 22.5KW . Not all the power derived from MG1 is devoted for battery charging in charge mode , but still it is greater than 3.3KW ...never did a 0-80% SOC in charge mode...but occasionnaly i do use it to burn some old gas and the charge level increases quite rapidely
     
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  6. Numtini

    Numtini Junior Member

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    I'm guessing the 3.3kw is the limit of the conversion from AC to DC?

    From a vacation in a hilly area, it can definitely charge faster from traction braking than you can charge it on a charger. There were a couple of times we were regenerating far faster than we could have charged it. I think we got 10% in like 10 minutes driving down Mount Holyoke in B mode.
     
  7. Trollbait

    Trollbait It's a D&D thing

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    It is for the onboard charger the Prius Prime is equipped with.
     
  8. tovli

    tovli 2023 Prius Prime replaced 09 Prius

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    Some more 2023 Prius Prime XSE HV Charge Mode data points:
    - 0-1% in 2 min at 35 mph = 3.2kW rate
    - 1%-27% in 49 min at 65-70mph = 3.38kW rate - 38 MPG (from range delta)
    - 27-30% in 6 min stop and go city = 3.2kW rate
    - 30-53% in 32 min at 45-55mph = 4.6kW rate - 38 MPG (from range delta)

    Total 0-53% in Total 89 minutes = 3.79kW average rate
     
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  9. tovli

    tovli 2023 Prius Prime replaced 09 Prius

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    10% of 10.6 kWh = 1.06 kWh * 60/10 min = 6.4 kW rate estimate or roughly 24 amps at 266v nominal

    Do you know what the SOC drop was going up that hill? (Or was up in HV mode?)
     
  10. Maxwell61

    Maxwell61 Active Member

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    Is'nt it odd that 45 to 70 mph the FE is the same 38 MPG?

    I'm looking to evaluate the cost of the kWh obtained with Charge mode: what would be the FE in Hybrid mode to compare with the 38 MPG?
     
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  11. tovli

    tovli 2023 Prius Prime replaced 09 Prius

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    UPDATE - MPG Computation was wrong - found spreadsheet issue


    - 0-1% in 2 min at 35 mph = 3.2kW rate estimate 29 MPG from range delta
    - 1%-27% in 49 min at 65-70mph = 3.38kW rate - estimate 28 MPG from range delta
    - 27-30% in 6 min stop and go city = 3.2kW rate - estimate 7.5 MPG from range delta
    - 30-53% in 32 min at 45-55mph = 4.6kW rate - estimate 43.5 MPG from range delta

    Best estimate (weighted by miles average) MPG = 33 MPG

    My current estimate of average HV mode MPG = 45 MPG

    These are averages estimated from estimates with too few measured actuals, so I'm putting these out but don't take these as gospel.

    (If the Distance To Empty indeed is based not on the full 10.6 gallon tank, but only 8.5 gallons til the 2.1 gallon low fuel light triggers, then my MPG based on range delta is bogus but that would make the car's estimate of MPG even more bogus 56 MPG. My "pump MPG" is 44.7 which matches the car DTE MPG computation when using 10.6 gallons.)

    Screenshot 2023-08-28 at 9.24.28 AM.png
     
    #11 tovli, Aug 28, 2023
    Last edited: Aug 28, 2023
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  12. Maxwell61

    Maxwell61 Active Member

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    There's a discussion in another thread about the Indicated MPG vs real FE (from refueling).
    In my experience with Toyota Hybrid, the Indicated MPG is affected by the same % of optimism of the speedometer, and I'm not the only to believe so. The value is in any case very close to most attempts to measure the tolerance using refueling.

    This is the most interesting data for me, and 43.5 MPG sounds very interesting and efficient, if we have to think of some 50-52 MPG in HV mode at the same speed. What you reckon you could achieve in HV mode in the 45-55 mph range?
     
  13. tovli

    tovli 2023 Prius Prime replaced 09 Prius

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    Totally unable to guess. Not enough data and very difficult to find a significant stretch of road for that speed range in my area.

    As I proffered and then retracted because it is just guessing - we are told gas has roughly 34 kWh energy per gallon. Pick some conversion efficiency, perhaps a WAG of 33% would recharge the Prius Prime's 10.6 kWh battery from 0-80% (8.5 kWh) using 3/4 to 1 gallon. At my current gas price of US$3.61 and my average full battery range of 45 miles, 80% (0.8 * 45 = 36 miles) yields a cost per EV from Gas mile of $0.10 ten cents per mile. BUT the 10 cent/mile cost is just a WAG! Even higher if the 33% conversion efficiency is optimistic.

    So its all just wild **** guessing.

    EV mode from wall: US$0.047 per mile
    HV mode (non-charging): US$0.075 per mile
    EV mode from HV Charge mode: US$0.10 per mile WAG, WAG, WAG!
     
    #13 tovli, Aug 28, 2023
    Last edited: Aug 28, 2023
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  14. Maxwell61

    Maxwell61 Active Member

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    Thanks for your replies @tovli, i do not know the prices of the kWh at US charging station, but i found myself with very high prices and long waiting time (and going back and forth to free the station) because of the very slow charging speed of the Prius.

    So i reckon that after a highway long stretch leading to a city, it should be cheaper and faster to use the charge mode for some city EV driving rather than charge at a station.

    EV mode from a public charge station will cost me 0,69 Eur/kWh (0,75$/kWh)....
    As soon i get the car i will drive the same route in HV and Charge mode to evaluate the cost of the kWh using gas (8.2 $/gal here)...
     
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  15. tovli

    tovli 2023 Prius Prime replaced 09 Prius

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    So $8.20 per gallon divided by 8.5 kWh (0-80%) is around 0.88 euro per kWh - again GUESSING!!!
     
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