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Prime really hates zero degrees

Discussion in 'Prime Main Forum (2017-2022)' started by Zed Ruhlen, Jan 15, 2024.

  1. Zed Ruhlen

    Zed Ruhlen Active Member

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    So it's gotten unusually cold here in Oregon and in the past few days every time I turn on the prime the engine immediately fires up. Haven't been able to run in EV mode at all for days. I've never had it this cold so it was a new experience for me. On the plus side you get a lot more heat :)
     
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  2. bisco

    bisco cookie crumbler

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    repeat after me: there's no such thing as climate change, there's no such thing as climate change...
     
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  3. Andy2

    Andy2 Member

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    Trying to upload picture of my car at -28 Celsius last week (about -18 F). Upload not working — maybe file size is too big?. Yes, engine comes on right away. Car still does go into EV on its own for some stretches. Today it started up and drove well at -36 Celsius! No issues.
     
  4. bisco

    bisco cookie crumbler

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    upload has been broken for awile, people have taken to linking offsite pictures
     
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  5. Zed Ruhlen

    Zed Ruhlen Active Member

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    I can't because my lips froze together
     
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  6. Zed Ruhlen

    Zed Ruhlen Active Member

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    Yeah, it's been fine except I have to sadly watch my cumulative MPGs drop more and more :cry:
     
  7. MalachyNG

    MalachyNG Active Member

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    Below about 14f and definitely below 0 the heat pump can't heat so if you're asking for any heat in the cabin it'll be more prone to fire up the gas engine and definitely will if you ask for front defrost. You can try to coax it to drive in EV by turning off the heat but with lower temps and snow you can expect pretty bad mileage anyway so it's a wash. Once the gas engine starts it'll keep coming back on to maintain operating temperature. Either you'll get 16-20 miles of EV range with a 2mile/kwh and then it switches to HV and still be 55ish MPG for a 40 mile trip or you can let it do it's thing and get a little better m/kwh and still get 55MPG for the same trip. I'd rather be comfortable. So I switch to EV auto on cold days or let it decide.
     
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  8. sylvaing

    sylvaing Senior Member

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    -10°C is the minimum temperature for the heat pump to work. However, if one was to NOT use the climate, just the seat and steering wheel heaters, would the engine still fire up? I've not driven in below -10°C so I haven't had a chance to experience it myself.
     
  9. ChapmanF

    ChapmanF Senior Member

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    Probably comparable work to just switching off JavaScript to upload them here, and then I can see them,
     
  10. Washingtonian

    Washingtonian Senior Member

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    I noticed this happening this week. I was sitting in the car waiting for my wife to finish shopping and the outside temp was about 20F. In EV mode, about 17 miles available from the HUD, heater on high to defrost the front window, and the engine suddenly came on. I remembered the car has a heat pump and that my home heat pump calls for the heat coils to come on at that temperature, so it didn't surprise me. My son has a Cadillac gas guzzler, and I am hoping he will drive it more to encourage Global Warming to return.
     
  11. john1701a

    john1701a Prius Guru

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    I answered that question an entire decade ago, with the original Prius PHV... at -19°C

    The engine stays off. Lithium chemistry will allow you to draw in surprisingly cold conditions (though with a big efficiency penalty due to in increase in electrical resistance), you just can't charge then.

     
  12. sylvaing

    sylvaing Senior Member

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    I see that when slowing down, it seems to recharge the battery. Was it the case or did you have to always engage the physical brake to slow down? Renegerative braking can send much more current (albeit for a shorter period of time) than charging alone. Was your battery temperature above freezing (ie, car was plugged in so the battery warmer was working while the car was parked)?
     
  13. Zed Ruhlen

    Zed Ruhlen Active Member

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    That's likely the issue and makes total sense. Thank you. The heat was has been on because, well, BRRRR.
     
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  14. Zed Ruhlen

    Zed Ruhlen Active Member

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    My drive home from work yesterday was in EV mode. Ahh, the bliss of 20F. And the battery was super unhappy about it, too. Range dropped faster than freezing rain in a wind storm.
     
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  15. DukeofPrime

    DukeofPrime Member

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    In my experience, turning on the front defroster always starts the engine regardless of temperature.

    SM-F731U1 ?
     
  16. sylvaing

    sylvaing Senior Member

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    Yes, that's how I turn on the engine after an oil change.
     
  17. Zed Ruhlen

    Zed Ruhlen Active Member

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    Yes, it's probably to operate heat and a/c at the same time. Which of course the heat pump is incapable of doing both. I wish you could direct air to JUST the windscreen without the a/c but that is not an option. Usually full fan on just the defrost vents is enough to keep up with defogging but if you have split level it isn't.