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Way to Purposely Half-Charge Prime with incorrect Departure Time?

Discussion in 'Prime Main Forum (2017-2022)' started by stevepea, Jun 3, 2017.

  1. stevepea

    stevepea Senior Member

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    Someone's lament in another thread (about how he couldn't take advantage of "B" Mode regen while going down a steep grade by his house in the mornings, as charging the car overnight already fills the battery up, and to prevent over-charging, the ICE comes on), got me to thinking:

    Is there a way to charge the Prime only 1/2 way at night, then?

    Obviously this would only be for unique situations, but if I remember the manual correctly, I think it mentioned that if you do a "Charge with Departure Time", and there's not enough time for a full charge, then (obviously) you won't have a full charge before your departure time. But I can't remember if it said if it will stop charging at your inputted departure time if it's not yet fully charged, or if it will keep on charging past your inputted departure time until it's full, or until you unplug it.

    I suppose I could try this myself, but was just wondering if anyone had any reason to try this out yet.

    (If your EV range is empty and you only want to charge it 1/2 way... say you get home at 8pm, then set "Departure Time" for 10:30pm that same night -- there's obviously not enough time for a full charge, but even if you don't actually leave until 7am the next morning, will it keep charging past the 10:30 departure time until full or unplugged, or stop at your inputted departure time of 10:30?)
     
  2. bisco

    bisco cookie crumbler

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    i think modem suggestedcthis in mr88's thread. seems like a good idea if charging from around zero.
     
  3. joachimz

    joachimz Senior Member

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    the only drawback i can see when unplugging while still charging is that the battery will be warm ... i do use the charge for departure time and typically it is done charging at least 1/2hr BEFORE the departure time, I suspect to let the battery cool off
     
  4. giora

    giora Senior Member

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    Departure time is no good, the car will calculate and start the charge to finish in time.
    If you know for sure your departure time in the morning, or it is a fixed time during workdays, set the schedule for 'start time' and calculate it to have partial charge.
     
  5. Lee Jay

    Lee Jay Senior Member

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    Yeah, it is. Just set to to after you want to actually depart. For example if you want a 90%-ish charge, set it for around an hour after you plan to leave. If you want a 50%-ish charge set it for around 3 hours after you plan to leave (assuming you're on L1).
     
  6. giora

    giora Senior Member

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    Yes, both will work, provided battery is empty (or at same SOC) each evening.
    With the PiP we have only 24 hr timer (no schedule) so I need to set it each evening, the plus is that i can take the residual charge into the calculation.
     
  7. Lee Jay

    Lee Jay Senior Member

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    The beauty of setting a departure time is that this is not necessary. All that's necessary is that the SOC is at or below where you want it to be at the end of the charge.
     
  8. giora

    giora Senior Member

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    Did you try it this way?
    If I remember correctly, with the PiP there were complaints about 'departure time' not taking into consideration correctly the residual charge i.e. finishing too early or something like this, but it could have been fixed with the Prime.
     
    #8 giora, Jun 3, 2017
    Last edited: Jun 3, 2017
  9. Lee Jay

    Lee Jay Senior Member

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    Every day I've owned it.

    It does finish early, most of the time, by something between 10 and 40 minutes. However, it's easy to account for this in your setup.
     
  10. stevepea

    stevepea Senior Member

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    At about 3:15pm local time today (with an empty EV charge) I set "Departure Time" to 6:00pm as an experiment -- under 3 hours later. Since that's not enough time for a full charge (5+ hours is needed at 120V), I want to see if using "Departure Time Charge" (with not enough time for a full charge) will shut off charging around the inputted departure time, or keep it charging until full.

    After entering "6:00pm departure time" at around 3:15 today (it accepted it -- I edited the previous departure input of 7:00am from yesterday morning to 6:00pm tonight) I went to plug it in. At first, the green light by the charger port blinked a couple of times (indicating a Departure Time charge rather than Charge Now solid green light) but after 4-5 blinks, the blinking green turned solid and charging began. I then opened up a car door to see if the display would show anything, and it said charging time would be 5+ hours. So I don't know if it will "shut off" around (or before) the entered 6:00pm departure time, or keep going past 6:00pm until full or unplugged. Will let you know.
     
    #10 stevepea, Jun 3, 2017
    Last edited: Jun 3, 2017
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  11. joachimz

    joachimz Senior Member

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    my guess is ... it will continue to charge ... the suspense is killing me ... another 85 min ...:p:D:LOL::)
    Thanks for testing it!
     
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  12. stevepea

    stevepea Senior Member

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    Continued to charge.

    At 6:05pm (5 mins after supposed "6:00 Destination Time"), charging was still going on, with a solid green light. Opened a door to see the display showing around 2hrs left for a full charge. I unplugged the charger cord, then got in the car, pressed the Charge Timer button to have a look, and it indeed still showed the 6:00pm Destination Time.

    So it appears if you start a "Destination" charge without enough time left for a full charge, it will just keep charging until full (or you unplug it).

    This is what I figured, but worth doing once just to see if it would cut off early and give you just a partial charge...
     
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  13. giora

    giora Senior Member

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    Is it arbitrary? Residual charge related?
     
  14. Lee Jay

    Lee Jay Senior Member

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    I think it's entirely about the accuracy of the estimate of the charge consumed, and therefore remaining.
     
  15. giora

    giora Senior Member

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    Same with the PiP, so it seems that they did not fix it. I use 'start time' constantly with the PiP because of that and the fact I have to activate timer every evening anyways.
     
  16. Lee Jay

    Lee Jay Senior Member

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    It always finishes by the time it estimates, and it's usually within about 20 minutes. Pretty impressive in my opinion.
     
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  17. alexcue

    alexcue Active Member

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    I've only had mine almost exactly a month, it's always early and as much as an hour off. Maybe it'll get better, but I guess earlier is better than later!
     
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  18. Rmay635703

    Rmay635703 Senior Member

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    I have used a hot tub spring wound timer for years to "limit" my EVs charge times, I put my timer in an enclosure with 10 gage cords, just set it for how many hours I want and forget, has an override if I change my mind.

    That said most EVs have a variety of charge timers to limit when or how long the car can charge, I've found them to be more aggravating than just setting the timer on the outlet.