Prime EV mode in very hot climates

Discussion in 'Prime Technical Discussion' started by DallasGuy, Aug 2, 2016.

  1. DallasGuy

    DallasGuy Junior Member

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    I've noticed that my gen 3 Prius will not function in EV mode when the outside temp is 100F or higher. Is there any info on if the gen 4 Prime will have the same constraint? I've moved to Palm Springs and if I can't use EV mode half of the year I'd like to know before I buy a Prime.
     
  2. 'LectroFuel

    'LectroFuel Senior Member

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    Does your car actually say that it's to hot to use EV mode? Does the battery not charge enough in 100°F weather? I would say that the Prius Prime would handle that temp. The new lithium ion battery pack in my gen 4 is a lot more powerful than my gen 2 nickel metal hydride battery. I can drive in EV mode in 100°F weather in my gen 4.
     
    #2 'LectroFuel, Aug 2, 2016
    Last edited: Aug 2, 2016
  3. DallasGuy

    DallasGuy Junior Member

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    My gen 3 will not switch into EV mode when the temp is 100F or higher. When I attempt to switch it to EV mode the dash beeps and says EV mode not available so yes the car is telling me EV doesn't work in high temps. The question is not about charging. The question is will the new Prime function in EV mode in high temps. No reason to buy a prime if the car functions like a regular Prius half of the year.
     
  4. GasperG

    GasperG Senior Member

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    I think that more than outside temp alone, it's important factor if the car is on the sun or not. Prime could come with cabin pre-cooling, battery is cooling with cabin air.
     
  5. CraigCSJ

    CraigCSJ Active Member

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    My Plug in Prius drives in EV when temperatures exceed 100 degrees. It is my understanding that battery degradation is greater if the battery is full and the car is parked in the sun when the temperature is high. For this reason, I would expect the Prime to use up its EV portion of the battery as soon as possible in hot weather. The default mode of my Plug in Prius always does that unless I operate it in such a way as to cause it to start the gas engine.
     
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  6. drash

    drash Senior Member

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    In that climate I would make generous use of the Remote A/C function. I have the base PiP so it's only available from my key fob. The Advanced PiPs have remote A/C available via their cell phone I believe. This will use up some EV but will save your battery especially when parked in the sun for a bit with EV left. But back to your question. Once in EV mode it will stay in EV mode unless it drops to about 15F which I assume that won't be a problem.

    If you would like to know more about Remote A/C and how it can use house current instead of EV range, I can explain its function in a bit more detail.


    Unsupervised!
     
  7. bisco

    bisco cookie crumbler

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    because the prime has pure ev function, it will be much better than the lift back. but that doesn't mean there won't be limitations. i don't recall reading anything yet, and it may be too early for a specification like that to be revealed.
    keep in mind, ambient air temp and battery temp may be two different things. toyota is more likely to reduce out put at battery temps exceeding certain parameters. but you will be able to find some of this info before purchasing, although, it may not be comprehensive enough for your satisfaction.
    a lot of good engineering data come from users, not toyota.
     
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  8. Trollbait

    Trollbait It's a D&D thing

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    The Prius has a much smaller battery pack than the PiP and Prime. For cooling, this means more surface area to the volume of the pack, and thus the ability to shed heat faster. The big advantage of the prismatic NiMH cells versus the standard cylindrical ones was that they shed heat faster. The Escape hybrid, and maybe the Honda ones had an A/C loop to cool the pack, where Toyota was fine with just a fan.

    All we know about the Prime's battery cooling is that it doesn't use a liquid system like the Volt. The Energi's are air cooled, and will reduce EV use when the battery gets too hot. The specifics on the Prime battery and cooling aren't out yet though. Newer chemistry could be more tolerable of heat, and there could be a supplemental cooling loop off the A/C for the battery. We just don't know at this point.

    As for the OP's PiP, are you able to monitor the battery's temperature? How cold do you have the A/C? Check to make sure that the battery vent isn't blocked or clogged. Try to listen for that fan. You might want to consider having the battery and it's cooling system checked out.
     
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  9. fotomoto

    fotomoto Senior Member

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    That type of information on operation hasn't been release yet.

    I can tell you that the Ford Energi series, which also use air cooling like the Prime, have an upper battery temp threshold of 113f when it will do the same thing as you described with your G3 and only drive in regular hybrid mode. NOTE: this is the pack temp not ambient outside temps. Level II charging outside in the afternoon sun and then using the pack hard (high speed driving) is a common way to trip this mode.

    The highest I've ever seen is 108f but I don't operate my vehicle in the above manner. Charging overnight and parking in the shade go along way to keep temps in check.
     
  10. bisco

    bisco cookie crumbler

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    i don't think the o/p has a pip, just trying to put his nimh lift back into ev mode.
     
  11. mmmodem

    mmmodem Taste Tester

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    Prius Prime EV does not equal Prius in EV mode. For example, Prius EV mode only goes up to 42-46 mph. Both PiP and Prime goes faster. EV mode on a Prius is not the same thing as EV mode on Prime. How many will buy a plug in that has to warm up the engine before EV mode is available like on a regular Prius? Very few.

    There's no reason to believe 100F will be an issue as my PiP operates at triple digits without issue as does my friends C-max Energi.
     
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  12. Trollbait

    Trollbait It's a D&D thing

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    In that case...
    EV mode on a non-plug in hybrid is a convenience function that many use as gimmick. Toyota's intended use for it was for shifting the car a short distance, like moving it out of the garage to reach the lawnmover, without the ICE turning on, or to keep the ICE off when leaving early in the morning or return late at night in order to not disturb your neighbors. I believe those examples where in the Japanese owner's manual.

    There is a list of a nearly a dozen conditions that will keep EV mode from operating in the manual. I believe Toyota didn't have EV mode available in the US at first, because they didn't want their dealers fielding calls from owners that didn't read the manual complaining about it not working.

    Using EV mode at the right time might improve overall fuel economy. It is easier to over use it and impair that economy.
     
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  13. bisco

    bisco cookie crumbler

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    heck, even pip has a list as long as your arm. some run into them more than others, for whatever reason. can't say i've had the opportunity to try ev in 100+ weather, thankfully.
    but i also think conditions before driving the car matter a great deal.
     
  14. DallasGuy

    DallasGuy Junior Member

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    Interesting idea. My gen 3 has remote AC from the key fob but is pretty useless as you have to be so close to the car to start the AC that you don't get any real pre cooling. I'd love to know how to pre cool a pip using house current so please explain more. Also the situation where I see my gen 3 won't go into EV mode offer 100 degrees outside is when I've been driving to work for about 20 minutes and I stop at the traffic light to turn into the parking lot at work. If I touch the EV button while stopped my gen 3 will go all electric into the parking lot if temps are 99 or below but not if the temp is 100 or above. I've tested this several times and awalys get the same result. Bottom line, this is not a pre cooling of the cabin situation because I've been driving for 20 minutes, always starting in my garage at home 20 minutes earlier. Since work is about 13 miles away from home I'm interested in driving there in all EV mode if I buy the upcoming Prime. I hope that will work at high temps and more importantly I hope I can get a very solid answer before buying!
     
  15. DallasGuy

    DallasGuy Junior Member

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    Thanks for the info. The vent for my gen 3's battery is clear and the fan seldom comes on (probable only 2-3 times during several years of ownership time.). I keep the cabin at 79F which in the desert is comfortable due to the extremely low humidity. I don't think cooling the cabin more (and chilling me) is energy efficient just to keep the battery cooler but hey, physics is physics. In my case, since I always start my trip from a shaded garage, I think outdoor temp is the key factor because if I try to force my gen 3 into EV mode after driving the same distance when at a stop light to go into the parking lot a work with temps 99F or below, it works and at 100F or above it doesn't. If you imagine paying extra for a new prime, backing out of the shaded garage into 112f temps and not being able to use the EV mode until cooler temps in October, you see my concern! I think the answe will only come from other drivers in a similar situation, and that may sadly delay my purchase decision at least until this time next year.
     
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  16. DallasGuy

    DallasGuy Junior Member

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    Thanks for the feedback on you pip experience. I have faith that Toyota will not take a step backwards with the prime!
     
  17. drash

    drash Senior Member

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    The EV mode in my Plug-in Prius (PiP) is the default mode if there is EV left. So if you start it up and there are EV miles left you stay in EV mode. When I want to precool my PIP while its plugged into the charger in my garage, I hit the A/C button on my key fob. The Remote A/C ALWAYS uses the battery but since my charger is 240V, it draws house current to replace what is being used by the battery and can keep up with the drain on the battery. If you plug into a 110V line the A/C will draw more than what is being replaced. And yes you have to be fairly close. Those with the Advanced model of the PiP can use their cell phone app to turn their A/C on. I'm assuming the Prime will have the same capabilities (Base - key fob, Advanced - cell phone app) except it will use a heat pump to help with cooling, much more efficient than just the A/C compressor. Supposedly the Toyota engineers made the Prime battery even more heat tolerant than the current PiP battery but that being said I have no idea what the upper limit is. The temps here only went above 100 once while I've had the car and after sitting in the hot sun for 10 hours it still stayed in EV and the A/C worked as expected. I would definitely take the Prime for a test drive but you might have to wait until next summer.
     
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  18. DallasGuy

    DallasGuy Junior Member

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    Thanks,
     
  19. 'LectroFuel

    'LectroFuel Senior Member

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    IMHO, the liquid battery cooling system in the Volt seems way more efficient than the air cooled system in most hybrids. Use the water that cools the car to keep the battery cool to the touch.
     
  20. Trollbait

    Trollbait It's a D&D thing

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    Water has greater heat capacity than air, so it will always be more efficient cooling. Also for heating, as the plug ins with it will heat the battery when it is too cold out. This reduces losses when charging and discharging the battery.

    The down sides to using it is that it adds cost and weight. For the shorter range PHEVs, air cooling should be fine. the Enrgi's have been on the road for a few years already without reports of mass battery problems from heat.
     
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