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 Active 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 Junior 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 Junior 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.
     
  11. Paul.Ivancie

    Paul.Ivancie Member

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    I have been using my home charger port for almost three years now, making maximum use of night-rate electricity to “feed the beast.” My brand-new ChargePoint® station has given me some heretofore unavailable and interesting information to ponder:

    I notice that when the traction battery is being “topped off” at the end of the charge cycle, the current draw is gradually tapered off, in stages, for the last half-hour or so. I have routinely (especially in the winter months) scheduled a warm-up prior to departure, expecting the car to use grid power to do so. But such is not the case. The car uses its traction battery to affect the warm-up (or cool-down in the summer). Then, at the scheduled departure time, it re-activates the charger to again top off the battery. During the thirty minutes or so that it takes to do this, the car's interior returns to the outside ambient temperature, making for an uncomfortable (and delayed) start to the excursion. If one chooses to start off at the scheduled departure time, the car's interior is prepared, but at the cost of EV range. There is plenty of grid power available, even at level 1, since the charging load is being tapered off anyway. I cannot fathom the decision that was made to program the charging and loading scheme this way. Can anyone elucidate me? AdTHANKSvance.
     
  12. CarlB

    CarlB Junior Member

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    Was wondering about the starter battery in cold weather. But the starter battery charges from the hybrid system, so no problem I can see in running in electric mode as much as the car will let you. If the ICE needs to start, the starter battery is charged and ready to start the engine.
     
  13. Salamander_King

    Salamander_King Senior Member

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    For PRIME and all PRIUS, there really is no "starter battery" for the engine. 12V battery is only needed to boot up the computer but the actual starting of the engine is done by traction battery.
     
    #13 Salamander_King, Mar 10, 2020
    Last edited: Mar 10, 2020
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  14. CharlesH

    CharlesH CA HOV Decal #5 on former PiP

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    Which is why, allegedly, one can start a Prius (or Prime) with 8 D-cells.
     
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  15. Acadianer

    Acadianer Member

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    Ok, this will be my first winter the Prime. I don’t have entune here in the great north. We don’t schedule the charging, we just plug in and leave it until we use it the next day. Is there any benefits to schedule the charging?
    I do tend to use a/c hold lately, but then notice it’s charging (blue lights flashing in front). If I’m using the a/c hold for 10 minutes, did I lose a considerable amount of range? I’ve noticed the cold temps have affected range, which is normal, but beside parking it indoors where it isn’t as cold, is there something elseI can do to help the range in winter? My commute is about 24.5kms on the highway or 30km if I take a rural route. I typically use highway to get to work, charge at work and rural to come back so it costs me less electricity here lol usually I would have. 20km left when arriving to work, but lately it’s 6-8kms left (highway). When winter really kicks in, I’m almost afraid the ICE will kick in before I arrive to work
     
  16. Salamander_King

    Salamander_King Senior Member

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    If your daily use of PRIME is predictable, then use of schedule for charging will minimize the degradation of the traction battery. Having the traction battery full (although it is not really full capacity) for a longer period of time is detrimental. By scheduling the charging you can minimize the time the car sits after the traction battery is fully charged. That being said, if your daily use is not predictable, then having the car sit with a full charge for a few houses occasionally is not likely to cause much degradation. If you plan to keep the car for a long time and want to keep the traction battery capacity, then try using scheduling.

    There really isn't much you can do to prevent the loss of EV range during cold winter. In my experience, PP loses almost half of the summertime peak EV range in the coldest days of winter. That is summertime EV range of 35miles (56km) is reduced to 18miles (28km). I also noticed that 2021 PP seems to have a higher temperature threshold for the engine coming on canceling the EV mode.

    If you have the ability to charge both at home and at work, then you should be OK for covering most of your commuting, but be prepared to see the engine coming on when you use a heater, defroster, and car under load. From experimenting in my case of ~36miles commuting, using HVAC setting at the lowest possible setting (No Auto, No AC, manually setting the fan speed to low, driver priority ECO setting) and use seat heater and switching to HV in moring time when the ambient temp is very low to use the engine heat and switching back to EV after the cabin warms up, and repeating HV/EV switching gave me better EV range with the use of gasoline. However, this practice is no longer an economical choice for me with the current higher gasoline price. In any case, you will likely be using some gasoline during the winter.
     
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  17. PiPLosAngeles

    PiPLosAngeles Senior Member

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    Schedule your charging so the battery is still warm from charging when you get in and drive. That should help a little bit. Maybe more if you have 240V charging available.
     
  18. AldoON

    AldoON Member

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    I've found similar issues when using pre conditioning to heat the cabin. Windows get really foggy.

    So far the only use I've found for pre conditioning is to keep me cool inside the car when I was stuck waiting a few hours for someone on a really hot day in a parking lot that conveniently had a L2 charger.

    Other than that, I find pre conditioning in hot or cold weather not useful and certainly not worth the hassle (I don't have Entune)
     
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  19. Tideland Prius

    Tideland Prius Moderator of the North
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    What @Salamander_King said.

    Scheduled charging reduces wear and tear by not letting the car sit at a full charge. Ideally, it finishes charging (and pre-conditioning) as close to the time you depart as possible.

    The side benefit is pre-conditioning and a warm battery. If you don't use cabin pre-conditioning (Climate Prep in the schedule menu), then the charging will finish close to the departure time. If you use cabin pre-conditioning, it typically finishes 30 minutes prior and then starts the 10 minute pre-conditioning, 10 minutes prior to departure.
     
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  20. Acadianer

    Acadianer Member

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    Is there a way to do both? Have a schedule at night, but be able to charge instantly at other times? During the week, I use it for commuting, but sometimes we use it in the evening to run errands or such, thus why I plug it in as soon as I arrive. We don’t have a level, just the factory level 1. I have been considering swapping out my 30a rv outlet to 50a though
     
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