Winter vs warm weather driving

Discussion in 'Clarity' started by PHEV Newbie, May 3, 2019.

To remove this ad click here.

  1. DucRider

    DucRider Well-Known Member

    The Clarity Electric is equipped with a heat pump, and it is a vast improvement over the Fit EV resistance only heater. At least in the "winter" we get in Coastal Oregon - less than half the range loss in all but the coldest conditions.

    There are heat pump systems that work well below freezing, such as the gas injection system on the Prius Prime:
    https://www2.greencarreports.com/news/1110627_how-does-the-heat-pump-work-in-a-toyota-prius-prime-plug-in-hybrid
     
  2. To remove this ad click here.

  3. David Towle

    David Towle Well-Known Member

    If you have no idea how it relates maybe sit and think a bit.

    No 40% is Honda's published figure for the Clarity engine.

    I guess you just don't get that fossil fuels are still what is used to generate most of our electricity, so all the same inefficiencies (including drilling, transporting etc.) that are applicable to ICE powerplants also apply to the electricity used in motors too.

    But our electricity system is getting better.
     
    HagerHedgie likes this.
  4. ryd994

    ryd994 Active Member


    I posted same words before, reposting:

    1. As @DucRider said, transportation of fuel wastes also has waste and pollution. Electricity can be generated somewhere far away and transportation is almost lossless. Once the grid infrastructure built, they can run for years.

    2. Car engine is far from efficient given weight and size constraints. A power plant can use all the heavy and huge devices to reduce pollution and improve efficiency. Do you really think the little engine in your car has higher chamber temperature and pressure and better cooling than a stationary power plant generator?

    3. Car engine is rarely working at best efficiency point. It must work under various load and rpm. In real life, you won't hit the 40% efficiency Honda claimed, which is measured in lab.
    In contrast, a power plant can control the generator to the best efficiency for the most of the time. The advertised efficiency is achievable.

    4. Even EV does not reduce any pollution and has as horrible efficiency as a ICE, it is still favorable by moving all the pollution away from city center, the most populated places.
     
  5. ryd994

    ryd994 Active Member

    drilling, yes, it's the same crude oil.
    transporting, no. For power plant, fuels arrive in oil tanker ships or oil pipes. For ICE car, fuel first arrive to a centralized warehouse, then distributed by tank trucks. There are so many gas stations around the city.
     
  6. DucRider

    DucRider Well-Known Member

    Fossil fuels are not used to generate most of my electricity. And this is true in many areas of the country.

    [​IMG]

    And the 40% thermal ICE efficiency is still half that of the electric motor, but indeed more than the 30% I credited.

    I'll stand by my statement that any vehicle is much more efficient using electricity than gas. The source of both fuels varies widely with a wide range of efficiencies in their production and distribution (with too many variables to be calculated by the consumer), but the vehicles themselves are easy to evaluate.

    How many BTU's are used in the exploration, drilling, pumping, transporting, refining, transporting, and pumping a gallon of the gas you buy? Do you know the source of your gas? High quality from the Middle East? Shale oil with extraction costs high, efficiencies low, and yielding lower quality crude that take more energy to refine with lower yields? Is it refined at an newer more efficient refinery?
    Add all those up and divide 45K (112K * 40%) by that total and the efficiency is? 5%? 15% 2%?
     
  7. To remove this ad click here.

  8. David Towle

    David Towle Well-Known Member

    Lucky you! You are then in the same fortunate group as Kentucky Ken.

    And I agree 100% with your efficiency statement, I just like to inform folks that EV powered cars are not quite as perfect as they think.

    Here's a couple more interesting facts re efficiency, ryd994 thought there was no waste in fossil fuels getting to power plants, not true at all. First here's the fuel distribution for power plants, only 0.6% is oil, versus 35% natural gas for instance:
    https://www.eia.gov/tools/faqs/faq.php?id=427&t=3

    And here's an idea of how much natural gas is wasted:
    https://www.forbes.com/sites/michaelkanellos/2015/01/29/the-mind-boggling-statistics-around-wasted-natural-gas/#23c0c6574775

    Plus it also mentions that manure is 9% of our methane emissions!

    The point of all these posts is energy is complicated, and its going to take a HUGE effort and many years for us and the world to get to the low emissions future everyone who bought a Clarity wants. I certainly wish more people felt the way we do.
     
    HagerHedgie likes this.
  9. HagerHedgie

    HagerHedgie Member

    I haven’t notice near
    agreed; range loss with AC is less than I expected after experiencing what running the heat does. Plus I hate getting sweaty. Being cold is no big deal.
     
  10. HagerHedgie

    HagerHedgie Member

    In cold weather, especially below 20F, the battery loses A LOT of efficiency due to internal resistance. Combine that with climate control and burning gas isn’t such a bad deal. In my case this only applies for 1-2 months out of the year.
    If you drive a lot of miles you’re burning fuel anyway.
     
  11. 4sallypat

    4sallypat Active Member

    Past 5 months, been getting over 50 miles per charge here in So Cal but now that A/C weather is upon us, I am using the open the windows to cool the car.

    I wonder if the drag created with the windows open vs. windows closed for A/C use - which is worse on my miles per charge ???
     
  12. To remove this ad click here.

  13. Robert_Alabama

    Robert_Alabama Well-Known Member

    I get such little loss with A/C use with the fan setting low that I wouldn't be surprised if at best it is a push, and the A/C might even win. I'm guessing, but I don't think the A/C is hitting me for more than a couple of miles of range (again with low fan settings), thermostat set at about 69, and outside temps lower 80s.
     
    HagerHedgie likes this.
  14. HagerHedgie

    HagerHedgie Member

    Agreed. The first few weeks when the weather warmed up here I was trying to avoid my AC use for the sake of efficiency but the difference was so small that lately I’ve just been turning on the air, staying comfortable and not sweating. I’m sure there’s some speed where the ac becomes more efficient than the windows I would imagine it’s in the 60s or 70s but that’s just a guess
     
  15. HagerHedgie

    HagerHedgie Member

    I wish Honda would have an “hv heat mode” that would just burn enough gas to heat the cabin(and the battery) and send all the torque to the generator. This would be perfect for people driving 80 miles a day like I do. Next winter I’m going to burn gas and stay warm. I’m sure I’ll still average 70mpgs.
     
  16. HagerHedgie

    HagerHedgie Member

    Energy transportation through the grid is anything but lossless. Losses range from 10% to over 60% depending on many factors. Transformers and length of the run are the biggest factors.
    The clarity was designed so that when the ice is running it stays as close to the 40% as possible.
    Don’t forget about energy expended in the manufacturing of the vehicle.
     
  17. The Gadgeteer

    The Gadgeteer Active Member

    Once the cabin is cooled down I am finding the AC even on minimal settings maintains the cabin comfortable without a noticeable range hit. Recycle vent mode makes all the difference.
     
  18. ryd994

    ryd994 Active Member

    1. 40%? Citation needed. I see 5%: https://www.eia.gov/tools/faqs/faq.php?id=105&t=3https://www.eia.gov/tools/faqs/faq.php?id=105&t=3
    "The U.S. Energy Information Administration (EIA) estimates that electricity transmission and distribution (T&D) losses average about 5% of the electricity that is transmitted and distributed annually in the United States"
    The wasted natural gas page you shared has nothing to do with production of gas. Those burnoff are byproduct of oil. They have to burned because we have too LITTLE, rather than too much need of natural gas. Nobody want's it, they only want the oil, and it's too dangerous to store the gas. What else can we do?

    2. Again. Citation needed. Honda claimed the HV will have better efficiency, but never claimed it will always reach the optimal efficiency. The power plant generator will have better efficiency than car engine. I've explain why it should. Feel free to provide opposite evidence.

    3. Sounds like gas car don't need manufacturing, and so don't engine oil .
     
  19. HagerHedgie

    HagerHedgie Member

    https://www.energycentral.com/c/ec/grid-efficiency-opportunity-reduce-emissions
    I was a bit misinformed. The grid is closer to 92% efficient on average. I was going off of memory and I must have lumped in production losses with my figure.
    The thing that really made me decide to just run HV more in the cold was the range. My cold weather range is less than 1/2 my warm weather range. If you factor cabin heating in the situation the clarity’s ice might run closer to 60% efficient since the heat is used for something.
    Don’t get me wrong, I’ll still use up most of my charge every day but I’m going to stay warm next winter. And if the heat is on so is my ice
     
  20. DucRider

    DucRider Well-Known Member

    The electric motors will always, under all circumstances, be more energy efficient than the ICE.

    Some weird morph has happened to what people are considering "efficiency" to be.
    It may be more cost effective to run on gas for some people in some circumstances.
    Power from the grid will usually produce less greenhouse gasses (well to wheels) than the ICE, depending on where you live, if that is your definition of "efficiency"

    [​IMG]
    https://blog.ucsusa.org/dave-reichmuth/new-data-show-electric-vehicles-continue-to-get-cleaner

    You can use the tool at fuel economy.gov to compare the Clarity BEV to an Accord Hybrid (47 mpg) to get a pretty close approximation to running from the grid or running the ICE.
    https://www.fueleconomy.gov/feg/Find.do?action=sbs&id=40044&id=39918&#tab2
    Under the Greenhouse Gas Emissions section, change it to show Tailpipe & Upstream GHG and note the total for the Accord
    Click the Calculate Emissions link for the Clarity and put in you zip code to get the upstream number for the Clarity (tailpipe is of course zero)
    The 47 mpg Accord Hybrid generates 227 g/mi (187 tailpipe + 40 upstream)
    Where I live, charging from the grid is 100 g/mi
    Denver is 270 g/mi (very coal heavy power mix)
    Washington DC is 140
    Atlanta is 180
     
  21. HagerHedgie

    HagerHedgie Member

    Thanks for the link. I enjoyed that information. I do think of efficiency in terms of the whole system. Of course the electric motor is much more efficient than the ice. It’s also a pleasure to drive. The beauty of this car is you get the best of both worlds. Gas still has certain advantages particularly in cold weather and in long distance driving. EV is generally cleaner and more luxurious. Of course those things vary from consumer to consumer based on personal driving habits and energy generation. I’m in MD so middle of the road as far as carbon emissions and electric cost. EV is cheaper for me until I turn on the heat in my car so I guess I’m a little biased. Before the clarity I’ve had two Prius so 40-50mpg is normal to me by now.
     
    David Towle likes this.
  22. Steve Caulfield

    Steve Caulfield New Member

    I'm with you, MNSteve. Here in Maine, the EV range only gets into the 40s when the temp gets back up to 50 or so. Finally saw the rated 47 mile range for EV mode when the temp topped 70 briefly. Oh, and don't get me started on the loss of "driver assists" when the ice covers that Honda emblem. There are still some cold weather bugs to fix. Must be nice to have one of these in the desert SW tho'.
     
  23. insightman

    insightman Well-Known Member Subscriber

    The HV battery doesn't like the heat in the desert SW, however.
     

Share This Page