2018 Prius Prime - Remote Engine Start

Discussion in 'Prime Main Forum (2017-Current)' started by SydneyNJ, May 23, 2019.

  1. Salamander_King

    Salamander_King Senior Member

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    I am no auto mechanic nor do I claim to be an expert on this subject, but my understanding is that idling engine 6-8 min is unnecessary for a modern engine with fuel injectors. The engine warms up quicker by just driving. That being said, PRIME uses a heat pump to heat or cool the cabin using traction battery power. However, the heat pump is not effective to heat the cabin at a temperature below 14F. At or below that temperature, ICE will come on automatically to provide heat. Also, ICE needs to come on if you have to use windshield defroster. In my region, the winter temperature gets down to below zero, and I do park my car on the driveway. I wanted to install the remote engine start on my PRIME so that I can pre-warm the cabin and run defroster to make scraping ice easier in the morning. But for normal driving, engine warm-up is never needed.
    Warming Up Your Car in the Cold Just Harms the Engine
     
  2. Salamander_King

    Salamander_King Senior Member

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    Only if its above 14F and there is enough traction battery charge.
     
  3. jb in NE

    jb in NE Senior Member

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    Even in very cold weather, engine warmup is not required or desired. More so now that almost all new cars use synthetic oil, which doesn't thicken significantly at cold temperatures.

    On an engine that is parked outside at temps down to -15F, I generally start it and let the oil pressure stabilize for about 30 seconds while I fasten my seatbelt and set the defroster/seat heaters, etc. Then drive it gently (no full throttle, no heavy acceleration) until the engine is warm. Keeping the cabin heat turned down helps the engine warm up more quickly.

    The engine warms most efficiently with some load on it, thus the recommendation to not idle it but to drive it instead.

    Another thing to consider - many of these aftermarket systems don't interface well with the existing car systems and the installers don't all do top quality work. Personal opinion - I wouldn't add such a system to my car.
     
    #23 jb in NE, May 24, 2019
    Last edited: May 24, 2019
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  4. john1701a

    john1701a Prius Guru

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    What a truly bizarre thread. The topic is about an owner wanting to override the system, rather than take advantage of what it was designed to deliver.

    Living in Minnesota, I simply don't understand why. Our winters are more harsh. The electric preheat and winter EV work just fine.
     
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  5. Salamander_King

    Salamander_King Senior Member

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    Do you keep your car in a heated garage? I know how cold it gets in Minnesota. I lived there. I now live in northern NE where winter temp does get below 0F occasionally. I have tested the Primes' preheating capability during my first winter and found it to be totally useless. The heat pump could not warm-up the cabin temperature even after repeated remote climate prep up to 30 min. It also did nothing to facilitate defrosting the windshields. Just for that reason, I was contemplating installing a remote engine start, but after discovering that it can not be operated with the plug in place, I decided not to.
     
  6. john1701a

    john1701a Prius Guru

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    The car sits outside exposed to everything the entire time I'm at work. Electric preheat works so well, I get greeted with a melty windshield on those days above 14°F.

    Colder than that, I can see the need to defrost windows from a cat that contained moisture prior to shutoff... but that's not what the OP requested. The follow up post implied it was for the engine, which is clearly not needed.

    Here's an example of my commute home, in much colder temps without plugging in:

     
  7. Salamander_King

    Salamander_King Senior Member

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    I don't dispute the fact that PRIME is very efficient even in extreme cold. The engine runs great down to -20F I have experienced here. EV also runs fine despite as everyone here knows at a reduced range in winter especially in severe cold with heat on. I get 30-35 miles of EV range normally but in winter I get only 18-20 miles.

    But that's not what I am asking. My experience has been that when the temperature is in a single digit or lower, the heat pump does not work to warm the cabin. If the temp is above 14F, I do not need pre-warming, but when it's much colder in winter, I wanted to pre-warm the cabin for comfort and to facilitate quicker scraping of thick ice that formed on the windshield overnight. Prime's heat pump is just not capable for that purpose. During my typical winter morning commute of 18 miles, ICE stays on even with EV run if I set the heat ON.
     
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  8. SydneyNJ

    SydneyNJ Junior Member

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    So my original post definitely diverged into other topics. I am just reading and absorbing what you guys are saying.

    I live in NJ definitely not as cold as MN but can get to < 0F below but I'd say our winter is ~20-25F (survivable). Someone said
    if the charging cable is plugged into the charging inlet on the PRIME and parked outside, remote starter will not (or won't) work.
    Right? What if my car is parked outside during winter months but charging cable is NEVER plugged into the car? Will remote start
    the car in gas engine?

    In one of my replies, I said what if I don't charge my battery during winter months? Let it go near empty so it's below the threshold
    for to start in EV mode. This should start the gas engine when I remote start the car regardless which driving mode I left at the night before. Right?

    Again, I don't care about preheating the cabin or defrosting the windshield at this point.
     
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  9. Salamander_King

    Salamander_King Senior Member

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    Yes. As far as I know, the remote engine start will work as long as the charge cord is not plugged in. The point was that unless you need the engine to start for the heater at below 14F temperature, prolonged idling of the engine is not necessary or even harmful.
     
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  10. john1701a

    john1701a Prius Guru

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    What is your goal?

    It's very difficult to provide suggestions without knowing what the purpose is.

    Keep in mind, the regular Prius has proven the system is robust without any plug or warm-up.
     
  11. SydneyNJ

    SydneyNJ Junior Member

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    My objective, very simple:

    1. Start the gas engine in cold winter months when I press the button on the remote starter.

    That's it.
     
  12. SydneyNJ

    SydneyNJ Junior Member

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    OK. I just spoke to the installer. They spoke to their tech support - the company that makes Viper.

    According to them, the Viper will simulate the same exact functions as if I start the car manually.
    They said the PRIME will start the gas engine in low temps when you press "Push Start" (manually)
    regardless if your traction battery is full or not. But because i bought my car in late April, I didn't
    have a good test in low temps. This is the part where I wish I could have the opportunity to test.

    The people who are responding this thread, does this sound right to you?
     
  13. Salamander_King

    Salamander_King Senior Member

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    According to the manual, as I said before, 14F or below with the heat ON will force the ICE to come on PRIME. Some people here have reported that temperature is more like 11F or below in reality. In my experience when the temp is in a single digit or below. ICE comes on regardless of the heater being ON or OFF. And you are correct that if you do not plug-in, thus has no traction battery charge, then ICE will come on almost immediately after you start the car. There might be a slight lag before ICE kicks in even when you don't plug-in, but it is very short.
     
    #33 Salamander_King, May 25, 2019
    Last edited: May 25, 2019
  14. SydneyNJ

    SydneyNJ Junior Member

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    OK. another update. I just called a local Toyota dealer. Spoke to one of the reps. They told me Toyota DOES NOT
    recommend leaving the traction battery low or intentionally not charging it. The PRIME is not designed to operate this
    way. I don't agree or disagree at this point because I don't know. And yes, if the battery has no (or low) juice, it has no choice
    but to kick the start the gas engine provided you have gas.

    Well I'm going to contact Toyota HQ next week and see what their story is.
     
  15. Salamander_King

    Salamander_King Senior Member

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    That's a new one. :ROFLMAO::ROFLMAO::ROFLMAO:I would not believe anything a dealer says about PRIME. :cautious:

    No charge left for EV does not mean that the traction battery is empty. It still has a reserve of charge needed to operate on HV mode just like a regular PRIUS.
     
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  16. john1701a

    john1701a Prius Guru

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    For battery longevity, you should indeed avoid being low all the time.

    If recharging routinely is an issue, just use charge-mode from time to time.
     
  17. john1701a

    john1701a Prius Guru

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    There's even enough reserve in HV to run a prewarm cycle.
     
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  18. SydneyNJ

    SydneyNJ Junior Member

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    Technically the traction battery can NEVER be empty!! It gets charged while you're driving. I was just saying keep the battery below the threshold so it can't start EV. I wasn't implying to go empty.

    Anyway you could conceivably get 5 different answers from 5 different techs working at the same dealership.
    Some are highly experienced while some are mediocre. The salesman I bought the car from new much less about
    the 2018 PRIME. He couldn't even explain the basics of PHEV. Ex: what mi/kwh meant? Unbelievable!
     
  19. Salamander_King

    Salamander_King Senior Member

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    I see the comments on the battery longevity issue quite often but seems to me the level of the traction battery charge is managed by the car to prolong the longevity already. Something like the upper 20% and lower 13% of the battery is not being touched during normal use. So is there really an issue on not plugging in the car and keep driving it HV mode all the time?
     
  20. bisco

    bisco cookie crumbler

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    unfortunately, both viper and the dealer are wrong.

    regardless of how much charge you have, if you set the temp anywhere above low and turn the fan on before putting it away at night, and it is not plugged in, the engine will start with the remote the same as it would when you press the go button.

    if your objective is to warm up the engine before leaving, it will work under this scenario.

    edit: i forgot about the heat pump. maybe setting the heat to high will override it and start the engine for heat, but maybe not, if it isn't cold enough outside.
    this could be an issue if there is enough wall charge in the battery.
     
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