How can I see my actual combined mpg with HV and ev combined?

Discussion in 'Clarity' started by Kingemail, Sep 28, 2020.

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  1. Kingemail

    Kingemail Member


    Yes I saw the power of thing a lot, those buttons are very confusing! I use to have the leave assist thing where my wheel would vibrate if Im getting out of Lane, but I somehow turned it off, but want it back again!

    Also, by using the left trigger thing behind steering wheel, does that slow down the car at all? I know with the volt it did, it used the whatever braking system
     
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  3. insightman

    insightman Well-Known Member Subscriber

    There are a series of carats (^) that appear at the top left of the instrument panel when you pull on the left (-) paddle. During normal driving you effectively have 1 carat of regen braking. When you pull the left paddle once, you get 2 carats of regen braking. When you pull the left paddle twice you get 3 carats of regen braking. When you pull the left paddle three times you get 4 carats of regen braking. If you want to reduce the number of carats, you can pull the right (+) paddle. In any mode other than SPORT Mode, the number of carats will return to the invisible default of 1 carat shortly. In SPORT Mode, your Clarity PHEV will retain the selected number of regen braking carats until you change them with the paddles.
     
    Kingemail likes this.
  4. LegoZ

    LegoZ Active Member

    I completely disagree here setting an equivalent amount of energy to a number that corresponds roughly with a gallon of liquid fuel allows you to have a combined efficiency score in a plug-in hybrid this allows you to gauge the efficiency of your driving he’s even an electric the harder you drive the more money you will spend. Honestly some people only care about gas usage which in theory then it should reset on the thing and it should go up to 9999.99 it does and also have an e-mpg Read outs for those who charge the car regularly yes still use each hv mode offense, and for those of us who use almost 100% electricity to drive the vehicle a miles/kWh or kWh per 100mi. As this is almost all done with software assuming the clarity has the ability to count the power passing through it.
     
  5. I completely understand the desire to know miles per kWh. It’s more or less the same as miler per gallon. We only need to know the battery capacity and the range that capacity is able to deliver, in order to determine miles/kWh. That range is quite variable depending on many conditions.

    What I view as a meaningless number is, what the EPA calls MPGe. They’ve taken the energy available in a gallon of gas, 114,000 btu’s, and converted it to ~33.5 kWh’s of electricity. Then they calculate, or measure how far an EV can travel on ~31kWh’s, probably to account for efficiency losses, and squirt out the MPGe figure.

    For the Clarity, the MPGe is 110, which works out to ~3.5 miles/kWh. Why not just say it gets 3.5 miles/kWh?

    Now throw in some freezing temperatures, turn on the heater and watch the numbers drop to 2 miles/kWh. The MPGe figure should be reduced to 62. They’ve cherry picked the conditions to produce the most desirable result. I those same conditions a gallon of gas may deliver 36mpg, rather than 42. It won’t drop by 40% or more.

    From a cost standpoint, 31 kWh’s may deliver 110 miles under ideal conditions. The same as 2.6 gallons of gas at 42mpg. In cold temps those kWh’s may only produce the same mileage as 1.5 gallons of gas. For each of us there are different considerations when determining what is most efficient.

    Combined efficiency score will now be added to the same category as MPGe.
     
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  6. I think the EPA's goal with MPGe is to provide a way to compare efficiency levels of various EV's out there.
    It feels good to pat yourself on the back for saving the planet with an EV but, naturally, there's a big range across the manufacturers and offerings.

    The Clarity PHEV is rated at 110 MPGe combined. The Clarity EV is 114. By comparison, the Tesla Model 3 Standard Range gets 141 MPGe while the Porsche Taycan Turbo S gets 68 MPGe. Obviously, Tesla's working very hard at optimizing their systems for efficiency. Porsche has different priorities.
     
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  8. MrFixit

    MrFixit Well-Known Member

    I agree with @Landshark here...

    It is just as valid (and more direct) to compare vehicles apples-to-apples using miles / kWh. That is what is happening... Electricity goes in (kWh) and miles come out. Just like a conventional vehicle where gas goes in and miles come out.

    A contrived figure like MPGe is different by a constant scale factor, but it just obscures what is really going on.
     
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  9. For an engineer or technical person it makes all sorts of sense. For the general public, 3.2 miles/kWh just looks unimpressive (a small number vs. a big number).
     
  10. MrFixit

    MrFixit Well-Known Member

    OK then... Make it miles/100kWh. Then instead of 3.2 it would be 320 !! Looks even better than the bizzare 110 MPGe :p
     
  11. ...but not relatable to the ICE cars that they'll inevitably be cross-shopping.
     
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  13. MrFixit

    MrFixit Well-Known Member

    This is exactly the problem. By specifying a figure like "MPGe" you are implying that you can relate it to a gasoline vehicle. You just can't (and therefore you are much better off with a figure that you cannot relate). For instance, people will think that the Clarity (with it's 110 MPGe figure) is twice as 'efficient' as a conventional hybrid that gets 55 MPG. It just isn't, and it leads people totally down the wrong road. You just can't relate electric operation to ICE. They are entirely different mechanisms, and they need entirely different figures of merit. Fundamentally, something like MPGe is assuming that electricity is free, and it is not.
     
  14. DucRider

    DucRider Well-Known Member

    MPGe is a bit bizarre and for some reason is the biggest number on the sticker (sometimes confused for range at auto shows and on dealer lots), but the Monroney also has both kWh/100 mi and gal/100 mi info.

    Running on electric is more efficient. I uses a much higher percentage of the energy of the fuel to actually propel the vehicle with much less lost to waste heat. Unless you have a different definition of "efficient" than something like (they vary a little):
    "utilizing a particular commodity or product with the least waste of resources or effort".
    Honda claims the Clarity ICE to be 40% "thermally efficient". An electric motor will be ~90+%, but getting the juice to the motor drops it by about 10% so 80% efficient.

    There is no assumption of electricity being "free". Annual fuel cost for the Clarity PHEV is listed at $650 (electricity + gas), for the Model 3 LR AWD it is $550 (electricity). This is based on 45% highway, 55% city driving, 15,000 annual miles and current fuel prices. Fueleconomy.gov allows you to personalize this to your specific use and fuel costs.
     
  15. MrFixit

    MrFixit Well-Known Member

    You are right of course.. I had forgotten the specific definition of eMPG.

    The fact remains that it was a poor choice to use a nomenclature on the sticker that so closely resembles the historical ICE MPG ratings. Many (most)? who are just starting to consider an EV may attempt to draw some conclusion by comparing this number to the regular old MPG they are familiar with for conventional vehicles.
     
  16. Let’s not forget that the electricity still needs to be generated. On average, in the US, more than 60% is generated from the same thermodynamically inefficient fossil fuels that some of us pump into our tanks. That kWh was generated from a 30-40% efficient energy source.

    A few percent is lost in transmission, 10-15% is lost forcing it into the battery and another 10-20% is lost to make the wheels go round and round. It’s 80% efficient once locked and loaded, but that doesn’t tell the entire story.

    MPGe is a deeply flawed energy conversion calculation that is presented in a deceptive and misleading manner.
     
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  17. DucRider

    DucRider Well-Known Member

    And lets not forget that it takes on average 6kWh of electricity to refine 1 gallon of gas.

    MPG and MPGe are not related to the efficiencies in producing the source fuel, only how efficient the vehicle is at converting that energy in to miles. They look only at the utilization of the energy put into the vehicle from the pump or plug.

    The efficiency of producing gasoline will vary greatly (low quality shale oil is one example), as will how electricity is generated. The EPA ratings only look at the vehicle itself, and do not even attempt to determine the "efficiency" of producing gas, electricity, hydrogen, or any other fuel source.

    MPG and MPGe are used to rate the efficiency of the vehicle. Nothing more, nothing less.
     
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  18. It is a flawed comparison.

    While a gallon of gas contains 114K btu’s, which converts to 33.5kWh’s, a gallon of gas will not generate 33.5kWh’s of electricity. A gallon of gas may generate 114K btu’s as a heat source. 33.5kWh’s of electricity may also generate 114K btu’s of heat. That would be a rational comparison.

    A gallon of gas may generate 10kWh’s of electricity. Put another way, it may take 3 or more gallons of gas to generate the 31kWh’s used as the standard for determining the MPGe figure. 3 gallons of gas would propel a Clarity 126 miles, while the 31kWh’s that the same amount of fuel would generate could propel the car 110 miles.

    Unfortunately, MPGe is the spawn of halfwit bureaucrats who get together to come up with brilliant ideas.
     
  19. DucRider

    DucRider Well-Known Member

    That's exactly the point. Engines that convert the energy contained in gasoline into a usable form are horribly inefficient. The Clarity is at or near the top by turning only 60% of the energy in the gas into heat instead of usable power.

    Your math doesn't make sense, since the Clarity (for all intents and purposes) runs only on electric motors and therefore electricity. Does it provide 126 or 110 miles worth of electricity (not that it really matters to the argument).

    Once again, MPGe defines how far a car can go on a defined amount of energy - without trying to figure out the efficiency of the production of that energy.
    MPG defines how far a car can go on that same amount of energy - without trying to factor the efficiency of producing that gallon of gas.
     
  20. And that is exactly why it is a flawed comparison.
     
  21. DucRider

    DucRider Well-Known Member

    OK, I'll bite.

    What is the efficiency of producing a gallon of gas?
     
  22. Perhaps Elon Musk can answer the vague question.

    From a Business Insider article dated 10/26/2011: “You have enough electricity to power all the cars in the country if you stop refining gasoline. You take an average of 5kWh’s to refine [one gallon of] gasoline, something like the Model S can go 20 miles on 5kWh’s.”

    Well, Mr Musk, my Honda Clarity can go 42 miles on the same 5kWh’s that it took to refine that gallon of gasoline, even when it’s 32F outside, with the heater on.

    Maybe we should stop generating electricity to power electric cars, until the source of grid power is derived from well below 50% fossil fuels.
     
  23. Pooky

    Pooky Active Member

    Fortunately, such is already true for our grid, and the story is even better for Washington state exclusively.

    upload_2020-10-3_11-45-2.png
     

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