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Prime Heater question...

Discussion in 'Prime Main Forum (2017-2022)' started by stevepea, Dec 26, 2017.

  1. stevepea

    stevepea Senior Member

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    In my older "normal" cars, using the heater would almost be "free" (no gas usage, and pretty much just the energy usage for the fan), while A/C usage would really eat into the MPG.

    But obviously the Prime is different. I posted a while back about how surprised I was at how little the A/C seemed to affect the MPG (in EV mode it was noticable but still excellent, in HV mode it was hardly noticable). So my question now is about the heater -- both while in EV mode and HV mode.

    If one wants to use the heater in cold weather, where is it drawing the power from? From the traction battery or the smaller 12V battery? Does the power source (and amount) change depending on if the car is in EV or HV mode?

    Let's take EV mode first. Has anyone done a test to see how much using the heater will drain the EV range, if at all?
    And then if the car is in HV... will it not draw as much power from the battery if the ICE is on (will it get some heat from the ICE instead?), or is it the same as EV mode? If the traction battery is completely drained (other than its reserve buffer), where does the heater gets its power from?

    If one still has EV range left, and has a choice of whether to drive in EV or HV for a particular trip, yet wants to use the heat, which would be the better choice?

    Again, in my old cars, A/C always came with a cost (MPG), but heat was pretty much "free" once the engine was warmed up. Just wondering how it works on the Prime. Though I've used the A/C (only a handful of times) in extremely hot weather, I haven't yet used the heater, though I probably will want to in the coming weeks...
     
    #1 stevepea, Dec 26, 2017
  2. bisco

    bisco cookie crumbler

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    there is a specific thread here with testing of all ev draw and corresponding miles lost.

    you have a heat pump. it is a single unit that can provide a/c or heat. it is electric, and runs off of the hybrid battery.
    if you are in hv mode, the heat will come almost free, like a gasser, and save you ev miles.
    i say almost free because a gasser never shuts down. with a hybrid, the higher you turn the heat, or the colder it is, the more the engine has to run, costing you mpg's.
     
    #2 bisco, Dec 26, 2017
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  3. Tideland Prius

    Tideland Prius Moderator of the North
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    Estimated EV penalties for various heating cooling and lights | PriusChat


    It uses a world's first (for a car) vapour-injected heat pump. I assume the pump is run by the 12V battery (with the traction battery charging it). traction battery.

    Basically it's reverse A/C where it extracts whatever heat it can from outside air and through compression, warms the air. The "vapour injected" part is that a small amount of something (refrigerant?) is taken from the expansion part of the cycle, expanded so it becomes vapour and then injected into the compressor (to allow it to run cooler).

    This apparently allows an increase of 20% in heating capacity at 0°F, basically making it more efficient to run.

    How does the heat pump work in a Toyota Prius Prime plug-in hybrid?

    Advanced Heat Pump Comes of Age in the New Prius Prime. Would this be a good option for Model 3 or the Bolt EV??


    The "free" part is basically the engine using more fuel than necessary and producing heat as a byproduct. The more efficient Prius/Prime will produce less heat as a byproduct because less fuel is used. If the heat pump is producing enough heat for you, then I 'd stay in EV (assuming your commute is short enough). If not, then I'd go into HV. Besides, you need to burn off that gas in the tank so might as well get something out of it (heat) and put a fresh tank of fuel in the spring.
     
    #3 Tideland Prius, Dec 27, 2017
    Last edited: Dec 30, 2017
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  4. Washingtonian

    Washingtonian Senior Member

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    Since our local temperature has gone from the 60s and 70s to the 30s and 40s, my EV mileage has gone from a consistent 27 or 28 miles to 23 or 24 miles. I attribute that to my using the heater, set at 70 degrees. It is a heat pump, powered by electricity and I suspect that I could improve my range by turning it off or using the seat heaters.
     
    #4 Washingtonian, Dec 27, 2017
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  5. bisco

    bisco cookie crumbler

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    but also less efficient charging, discharging and driving. i don't have heat, but my range drops as soon as the temp goes below 70 or so.
     
    #5 bisco, Dec 27, 2017
  6. priuscatprimeguy

    priuscatprimeguy Senior Member

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    When we had a snowstorm a couple of weeks ago I used the "EV heater" my range was 12 miles. does that answer your question?
     
    #6 priuscatprimeguy, Dec 27, 2017
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  7. ct89

    ct89 Active Member

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    Coupling this conversation to another thread...
    How big a battery would you then want with a pure-EV car?
    Many of us are experiencing sub-20 mile ranges as the temperatures drop below freezing. 12 miles is really low.
    Sounds like we need Toyota to building batteries 15-20x the current size to get descent range in the winter.
    And I thought the trunk space was limited in the current version.
     
    #7 ct89, Dec 27, 2017
  8. Dudley1030

    Dudley1030 Active Member

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    There is a screen on the dash that shows how many miles you have if you use the climate control or without. I think if you're on the screen with the efficiency/power graph and go up 2 or 3 times and you will come to it.
     
    #8 Dudley1030, Dec 27, 2017
  9. huskers

    huskers Senior Member

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    Come on Spring !!!! -10 here now.
     
    #9 huskers, Dec 27, 2017
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  10. priuscatprimeguy

    priuscatprimeguy Senior Member

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    Since I'm paying $15.00/mo to use my landlords electricity I used a hair dryer to thaw out my windshield, the car was facing the sunshine so I hurried it along with the hairdryer:p outside temperature says +8 F here. drove to grocery store all EV told passengers to quit breathing because I have to open the windows a crack to stop the fogging:eek::LOL:
     
    #10 priuscatprimeguy, Dec 27, 2017
  11. bisco

    bisco cookie crumbler

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    50 miles pure ev works for me, we have another car for the few times i go further.
     
    #11 bisco, Dec 27, 2017
  12. Lee Jay

    Lee Jay Senior Member

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    #12 Lee Jay, Dec 27, 2017
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  13. Tideland Prius

    Tideland Prius Moderator of the North
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    Hmm, yeah now that I think about it, the 12V probably doesn't provide enough power. Oops.
     
    #13 Tideland Prius, Dec 27, 2017
  14. Salamander_King

    Salamander_King Senior Member

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    Our morning temp is dipping into sub zero. I am driving HV all the way to work (18 miles) and saving all EV range for my afternoon commute back home. I can get home without using gas this way.
     
    #14 Salamander_King, Dec 27, 2017
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  15. CraigM

    CraigM Active Member

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    Running the A/C at 70 degrees? That’s why they sell jackets, sweatshirts, gloves and warm socks. Man-up! :) I keep my A/C set at 63. Heck, my house is set for 65 and I just wear a long sleeve shirt.

    Slightly joking, but 70 degrees is too warm for me.
     
    #15 CraigM, Dec 27, 2017
  16. stevepea

    stevepea Senior Member

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    Sorry it's taken so long to log back in, but thanks for the replies, everyone! So heat isn't "free" in the Prime the way it is in gassers... ah well, that's one of the tradeoffs I guess. Living in SoCal, there aren't many nights where it's that cold, but I know there will be a few times where I'll want to use it. Thanks for all the data!
     
    #16 stevepea, Dec 30, 2017
  17. Lee Jay

    Lee Jay Senior Member

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    Heat isn't "free" in gassers either. Not only are you paying for it all the time whether you're using it or not, but you're also paying to get rid of it through drag on the cooling system.
     
    #17 Lee Jay, Dec 30, 2017
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