While it's happily charging, questions

Discussion in 'Prime Technical Discussion' started by Skylis A, Sep 18, 2017.

  1. Rieuk

    Rieuk Member

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    Did this ever get fixed? Is it actually supposed to be 20 mins even while charging? My PP still shuts off after around 60 seconds while charging.
     
  2. Lee Jay

    Lee Jay Senior Member

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    I reported several easily reproducible software bugs to them and, to my knowledge, they've never fixed any of them.
     
  3. Old Bear

    Old Bear Senior Member

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    That's interesting. According to the power metering device which we installed on the circuit supplying our EVSE, our Prime continues to draw power even when fully-charged. It's only a fraction of an amp, but more than used by the EVSE by itself.

    We usually leave our Prime connected to the EVSE whenever it is parked in our garage. We left it there for ten days while on vacation last summer and had no issues when we returned.

    I had a car many years ago that would have a dead battery when left parked for more than 48 hours. The problem was finally traced to a defective tilt switch which kept the trunk lid light on even when the trunk was closed. If a small incandescent bulb can kill a battery in a mid-sized car in 48 hours, the Prime must be drawing very, very little current from its 12-volt battery when left connected to its EVSE.
     
    #23 Old Bear, Jan 4, 2020
    Last edited: Jan 4, 2020
  4. Bill Norton

    Bill Norton Senior Member

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    Holi Moli....

    You mean I can't leave a Prime plugged in at the airport L2's in the winter for a few week vaca,
    and return to a car with a decent temp in the HV battery pack and the 12V battery at a normal state of charge?

    The 12V battery will be discharged (and possibly destroyed in sub freezing temps) ???

    Is that really the case?
     
  5. bisco

    bisco cookie crumbler

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    would you really tie up a public evse for two weeks?
     
  6. Bill Norton

    Bill Norton Senior Member

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    I know what you mean. I call it the 'Airport Conundrum'.
    There are currently 24 L2's in each of the economy parking lots.
    There is no valet service.
    They are never close to being fully used. Yet !;)

    So yes, in KC plugins are left plugged in for the duration of an airport visit.
    That way your HV battery pack is always kept in a proper temp range, in the winter and in the summer.
    I can see the TMS cycling on the ChargePoint app for many days.

    NOW, back to the question:
    Will a Prime left plugged in for 2 weeks in the dead of winter RUIN its 12 Volt battery,,,
    because of shoddy engineering of the 12 V system? I find this hard to believe.....but i guess if you RTFM...
     
  7. bisco

    bisco cookie crumbler

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    that would take analysis of the quiescent drain, battery health and climate. which is why toyota offers no specifics. same with the hybrid battery.

    i can't say why they determined that systems need to run if it remains plugged in.

    but in the larger scheme of things, it is a great car with very few problems.
     
  8. Old Bear

    Old Bear Senior Member

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    The telecom transceiver never sleeps. The Prime is always waiting for a call from the Entune server giving instructions (e.g., turn on climate) or requesting status (e.g., charge management query, location query.)

    Tending those ECO dashboard sheep requires constant vigilance!
     
  9. m8547

    m8547 Active Member

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    The relay in the EVSE is disconnected when the car is not charging, even if it's plugged in. I don't see how the car could be drawing any power. Maybe the circuit in the EVSE is active because it seems the car plugged in, and the car could start charging anytime, rather than in sleep mode waiting for a car.
     
  10. Bill Norton

    Bill Norton Senior Member

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    Right.
    Plus the Key fob receiver, both methods of unlocking the car (buttons or touching the door handle) requires an active receiver.
    This is a common draw on the battery with ALL modern cars.
    Right.
    Why would having the EVSE plugged in draw more power from the 12V battery than if it is not plugged in?

    That is the question.

    Evidently when the car is plugged in the 12V battery never gets charged.
    And this is why you have that warning statement in the Owner's Manual?

    So what happens when you leave a Prime plugged in during really cold weather for weeks because you want the TMS to keep the battery warm?
     
  11. m8547

    m8547 Active Member

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    I think we need some context... The increased 12V draw line is in the "if the vehicle is not used for a long time" section.
    upload_2020-1-9_8-48-52.png

    Based on other hints in the manual like starting it every 2-3 months, 2 weeks is probably not considered a long time.

    The traction battery heater works for up to 3 days:
    upload_2020-1-9_8-51-20.png

    The mysterious Alaska and Canada "Hybrid battery (traction battery) warming control) works for up to 31 days. It's not clear how this is different from the traction battery heater, or what it means to insulate the battery. I wonder if it is a poor translation of warming the battery.

    upload_2020-1-9_8-52-4.png


    Anyway, based on the fact that the heater only works for 3 days, I don't think it would be worth it to leave it plugged in for 2 weeks. It wouldn't be warm when you get back, and the battery would stay fully charged for the whole time, which is not ideal. While charging, the car powers the 12V system from the charger to run the fans, and in fact the battery heater is a 12V device. But based on reports here it sounds like it doesn't actually try to charge the 12V battery during that time.
     
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  12. jerrymildred

    jerrymildred Senior Member

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    Clarification on a side note not directly related to long-term plugging in:
    While charging the traction battery, the car also trickle charges the 12V battery. The trickle charge starts when traction battery charging starts and stops when the traction battery charging stops. I verified this with with a multi meter on my 12V. It does not trickle charge as hard as the PiP, but it still does charge.
     
    #32 jerrymildred, Jan 9, 2020
    Last edited: Jan 9, 2020
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