Pre-conditioning - Heat

Discussion in 'Prime Technical Discussion' started by Tideland Prius, Dec 13, 2019.

  1. Tideland Prius

    Tideland Prius Moderator of the North
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    Those in humid climates, have you noticed that the pre-conditioning on scheduled charging doesn’t use the A/C compressor? Or is it just my vehicle? I have gotten into the car that feels humid and occasionally a slightly foggy windshield at the base where the vents are.
     
  2. Salamander_King

    Salamander_King Senior Member

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    I don't use pre-conditioning because when I really want that function it is too cold for the heat pump to operate. That being said, your question brings the point I have been asking in other threads.

    For the PRIME's six different climate control modes: cabin cooling, cabin heating, serial dehumidification, parallel dehumidification, defrosting, and heat-pump generated cabin heat, which one can operate for the pre-conditioning? Can it do both heat and dehumidification? I don't know the answer, maybe someone else does...
     
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  3. Tha_Ape

    Tha_Ape Member

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    I use pre conditioning, but the car is in a garage where the temp is in the 50s. (~20-25deg Warner than outside.). Ive never had foggy window .

    However, when I used remote climate (sometimes I leave later than scheduled) on max heat, my windows were foggy (moisture on inside). Another day I used remote climate on max heat but turned on both defrosters and it was much better.

    Im not sure what pre- conditioning uses, just giving more data points as to what's possible.
     
  4. Tideland Prius

    Tideland Prius Moderator of the North
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    Unfortunately we don't have Entune on our cars so I'm limited to the remote fob or the charge schedule for pre-conditioning. I can't use max heat/cool or turn on the defrosters.
     
  5. drash

    drash Senior Member

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    I ended up turning off the A/C on my climate controls in the car because the timed charge with pre-conditioning was fogging up the car. I’ve experimented a little by setting the climate control to Max Heat (without A/C) before I shut off the car and it does the same thing as me setting it to Max Heat on Entune Remote Climate. But too much hassle setting it before I shut down and resetting back to habitable temps when I leave. I just use Max Heat with the Entune Remote Climate and it warms up the interior nicely plus warms up the heat pump as well for my next trip. Keeps the car in EV mode for my entire ride into work even when temps go down to single digits. I’ll find out later this week when temps are forecast to hit negatives when I go to work if I can get this to stay in EV.

    Of course this is all done while the car is parked in my garage which can get quite humid from all of the rain and/or melted snow. I’m assuming a damp heat pump will bake off the humidity easier than introducing more humidity by starting the A/C since it starts off cooler and attracts the humidity. So if you are looking at the diagram of the Prime’s gas injection heat pump system, I’m relying on just the Internal Condenser and bypassing the Evaporator because it’s quite a bit cooler and will take longer to warm up.


    Unsupervised!
     
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  6. Darkly-Noon

    Darkly-Noon New Member

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    My car is always parked outside and I tried pre-heating the cabin while charging in the morning. Often the windows would be very fogged up and take a long time to clear before I could set off. I'm in Ottawa Canada and the climate here is both cold and humid (we're in a valley). I tried shutting off the pre-heat this week and it seems be better, with much less fogging This is my first winter with the car.
     
  7. Old Bear

    Old Bear Senior Member

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    If you're able to use the Entune 2.0 pre-conditioning function, you have the option of setting the temperature (min, last setting, max) and the front and rear defrost functions:

    Entune-Pre-Conditioning.jpg

    A lot depends upon the ambient temperature and humidity where the car is parked: whether it's in a heated/unheated garage, outside on a sunny day, buried in snow, etc.

    And, there is always the option of manually de-fogging the inside of the windows by keeping some absorbent disposable paper product in your car:

    absorbent-paper-product.jpg
     
  8. P.Neophyte

    P.Neophyte New Member

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    I would like to know if plugged in pre-heating warms the engine coolant, and thereby gives at least passive warming to the engine reducing start up wear in severe cold? Or, does plugged in pre-heating only warm the cabin and battery? If the latter, then conceivably you could have a warm cabin, depart on EV, accelerate to highway cruising speed (70mph) until you've exceeded battery range, and then the ICE kicks in when it is stone cold at a high rpm. Seems tough on the ICE in severe cold. Looking for real world experience.
    Full Disclosure: I do not own a Prime Advanced, but intrigued with the engineering.
     
  9. Tideland Prius

    Tideland Prius Moderator of the North
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    Plugging in doesn’t do anything to the engine coolant. You’ll need an engine block heater to pre-warm the engine.
     
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  10. Salamander_King

    Salamander_King Senior Member

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    Preheat is only for the cabin warmth using a traction battery operated heat pump only down to 14F. Switching from EV to HV is managed in such a way that the remaining traction battery will provide substantial traction power until the engine completes the warm-up cycle. That being said, in the very cold morning (below 20F), I always start my car with HV and run HV to warm-up the engine first and use engine heat for my warmth. Preconditioning for me is worthless, for I really do not need that function in temp the heat pump is effective.
     
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