Should Electric Vehicles Be EPA Rated For Both City And Highway Range?

3 years ago by Eric Loveday 39

Chevy Volt EPA Ratings

Chevy Volt EPA Ratings – Should There Be A City And Highway Electric Range Figure?

EPA Rating For Nissan LEAF

EPA Rating For Nissan LEAF

Mark Renburke, a Chevy Volt owner who lives in Connecticut, posted the following to the Chevy Volt Owners Facebook site:

“A recent post started me thinking – wouldn’t it make more sense to rate electric range for both city and highway like gasoline cars? I think the positive effect on adoption based on the city range would outweigh the negative highway number, as most people are getting plug ins for urban driving anyhow. For example, the current Volt might be rated for 45 city AER and 32 highway, or the LEAF for 100 city and 65 highway. It would give people both more encouraging and realistic expectations. What do you think?”

Well…what do you think?  Would knowing the city and highway electric range of all plug-ins in America be a useful bit of information?

Mark adds that he’s very interested in the responses and ideas” because his organization (Drive Electric Cars New England) is “gearing up for some major 1st-person education initiatives.”  So, your input is greatly appreciated.

Collectively, we at InsideEVs feel this would be a step in the right direction.  Do you agree?

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39 responses to "Should Electric Vehicles Be EPA Rated For Both City And Highway Range?"

  1. Yeah, I think this is a great idea. I spend a lot of time trying to talk to people about EVs, and my answer to “how far can it go on a charge?” is always, “it depends”.

    1. Nathan Crawford says:

      If you click the “Personalize” button on the comparison page, you can set the percent of city/highway driving. This updates all the economy and range numbers. You can also edit driving distance and fuel prices to adjust your 5-year savings over the 23mpg average vehicle. Neat!

    2. Emc2 says:

      Did you get the link right? EPA only provides ratings for city and highway driving for fuel economy, not all-electric range.

      i do think it will be very useful indeed to provide the AER for both environments since PEVs strength is in urban driving, and particularly I think it will contribute to improve plug-in hybrid sales. People will be surprise to learn how much city driving can be achieved in all-electric mode.

    3. mike w says:

      The link you provided shows only GAS mpg ratings for city and highway. The electric number is an average. I’m thinking they are asking if you want the Electric numbers broken out for city and highway, like the gas numbers are. To which I would say YES it would be nice to have all 4 numbers not the 3 they currently give.

  2. Warren says:

    Oops! Plug-in hybrids DON’T give electric range broken down for city vs highway. That is bizarre. BEVs get rated for both. Why not plug-in hybrids?

    1. Eric Loveday says:

      True…but those figures don’t appear on the window sticker. So, the typical consumer never sees that.

    2. K-lein says:

      Because the sticker is standardized and only has room for two figures.

      Doing city/highway for plug-in hybrids would require a different sticker, which is absolutely unacceptable : people are too stupid for that ! That’s too much information for stupid people, they’d be lost, they wouldn’t understand, they’d be an easy prey for evil Detroit corporations.
      So they keep only two figures max.

      It’s also the reason why they decided to use that weird MPGe thingy even for electric cars instead of using the most logic miles per kWh.

      Americans aren’t the worst.
      In Europe, people are so stupid that the EU had to hide electric efficiency completely from stickers. Electric cars use no gas, that’s all that matters.

  3. David Murray says:

    I agree – I’ve been thinking this for some time.

  4. ffbj says:

    When I get my utility bill it ranks me compared to others with similar sized homes. I rank in top 5% btw in efficiency. So a class efficiency rating, for each vehicle, how much fuel/power does it take to run the thing. This vehicle is in the top 5/10/15% etc… or use 95%,90%, etc… since people think higher is better.

  5. lewl says:

    I think manufacturers should only be allowed to advertise based on the lowest value, be it city or hwy.

    This both gives a realistic number for the consumer, as well as encourages manufacturers to improve efficiency across the board.

    For example, in ICE cars, they all tout about 40MPG these days. Well that’s a steady speed and pretty easy for any car to do. What good is that if you drive in the city and only get 20MPG.

    If they had to advertise on that embarrassing 20MPG, we’d see huge strides to improve efficiency where it matters most.

    And this carries forward to the EV discussion – if you buy a car advertised at 120km, you know that’s AT LEAST 120km, not “you can possibly, on a nice warm day, coasting at 50km/h, get 100”.
    You can reasonably assume you’ll get 120km out of it on the hwy, more in town (bonus!).

    Obviously doesn’t account for winter heat demands, etc, but it’s a start.

  6. Even the dual city/hwy ratings for battery electrics only are not that useful to the consumer, because they are in MPGe, not actual vehicle electric range. So for example, additional calculation is required for the consumer to figure out that the 84 mile combined rated range for the BMW i3 is actually rated at 94 miles for city driving.

    1. Eric Loveday says:

      These city/highway figures are out there, but they’re not publicly displayed. For example, the EPA says the 2014 LEAF returns 92 miles of range in the city and 74 highway for a combined 84 electric mile rating.

      1. liberty says:

        They should be easier to see on fueleconomy.gov all the individual tests should be transparent on the website. Lets face it on the car label there is enough information, adding more makes them harder to read, but when researching the website should make all the information transparent.

    2. While Highway Ranges is not explicitly listed on EPA sticker, City Range is on the EPA sticker and the sticker references FuelEconomy.Gov website with related stats.

      eg: 2015 LEAF is listed at
      http://www.fueleconomy.gov/feg/noframes/34918.shtml

      Combined: 30 kWh / 100 miles = 0.30 kWh/mile
      City: 27 kWh / 100 miles = 0.27 kWh/mile
      Highway: 33 kWh / 100 miles = 0.33 kWh/mile

      Knowing a LEAFs usable ‘City Range’ listed as ’84 miles’ tells us the battery pack’s usable capacity is: 22.68 kWh.
      http://www.fueleconomy.gov/feg/Find.do?action=sbs&id=34918

      City: 84.0 miles (EPA listed range)
      Highway: 68.7 miles (22.68 kWh / 0.33 kWh/mile)
      Combined: 75.6 miles (22.68 kWh / 0.30 kWh/mile)

      note: if kWh/100 miles is missing, can take 33.7 / MPGe value to get kWh/mile.

      Combined: 114 MPGe –> 33.7/114 = 0.296 kWh/mile
      City: 126 MPGe –> 33.7/126 = 0.267 kWh/mile
      Highway: 101 MPGe –> 33.7/101 = 0.334 kWh/mile

      Differences in kWh/mile from above are related to MPGe values having 3 significant digits vs. the two significant digits given with kWh/100 miles.

      So EPA does provide City & Highway Electric Ranges … they just like to hide values in plain sight. 🙁

      1. Jay Cole says:

        The LEAF is EPA rated at 92 miles city, 74 highway, combined is 84 miles (the weighted split is between the two is not the same). The only place you will find this information (and only on fully electric vehicles) is under the methodology/data disclosures.

        It is far, far from being in plain, I imagine most have no clue the data is even out there.

        Just for fun, here is a couple other BEV ratings.

        Tesla Model S (85) 262.7 city/266.8 hwy – 265 combined
        BMW i3 89 city/71.6 hwy – 81 combined
        Focus EV 79.8 city/71.5 – 76 combined

        1. City:
          92 miles city at 0.27 kWh/mile would require 24.84 kWh of usable battery capacity. (92 miles * 0.27 kWh/mile)

          Highway:
          74 miles city at 0.33 kWh/mile would require 24.42 kWh of usable battery capacity.

          How can it be that more energy is required to match the range than can be contained in a LEAFs 24 kWh battery? The most likely answer is ReGen (breaking) as drive cycles contain stops and starts.

          Thanks @Jay for that EPA ranges, do you have a reference or URL?

          1. Jay Cole says:

            Yeah I do Brian, I’ll link and/or email the file to you once stop travelling at some point today…big pain on the cell to do much hunting around, (=

          2. Kurt Endress says:

            I believe the EPA rates on the electricity used to charge the car, not the electricity coming out of the battery. There is something like a 15% loss involved in charging. That’s how 24.84 kWh goes into a battery that can’t hold that much.

            1. Yes @Kurt, while there are loses in charging, the charger* is not plugged-in while driving.

              The additional energy (over 22.68 kWh) is from regen. As you note the actual regenned amount of energy would be higher, but some energy is lost as motor recharges the battery. The only way to know the amount of regen is to run each test twice; once with regeninng enabled, and once with regen disconnected. The difference would measure efficiency of the regen system, something current testing does not take into account. The test process pre-dates hybrid and EV drivetrains and assumes a single energy source (just the energy stored in a tank, not that the tank is being refueled with energy while driving).

              *The spec for the onboard 6.6 kW charger states an input of 6.6 kW will yield a 6 kW charging rate. Add in loses at EVSE and 10-15% lose is what can be expected.

              1. JakeY says:

                The EPA test procedure is to fully charge an EV then leave it overnight. Then next day (24 hours) drive it on the EPA cycle until it can’t go anymore and come up with the range number (84 miles combined for Leaf). Then the next number to measure is the amount of AC electricity (from the EVSE) it takes to fully charge the EV after this procedure (25.2kWh for Leaf). They do NOT measure the DC electricity from the battery (which is what you are assuming).

                They calculate the efficiency rating by taking the kWh and dividing by miles (25.2kWh/80 miles = 30kWh/100 miles). A small detail is that they do (city, highway, and 3 other) cycles separately and use a formula to figure out city/highway/combined, but for my exercise I just used the combined value to simplify the match.

                So Kurt is correct that the extra energy is because of charging losses.

              2. @JakeY,

                You are correct, the J1634 test methodology used does calculate and use the on-board AC charger effiency.

                Details of the calculations can be seen in slide #6 (& #7).
                http://www.cse.anl.gov/us-china-workshop-2012/pdfs/session4b_demos_standards/duoba_4B-2-Duoba-ANL-Standardizing-Vehicle-Dyno-Test-Aug22-2012.pdf

                Note the:
                Recharge Allocation Factor (RAF)
                RAF = DC kWh (total test) / AC kWh (recharge)
                For 2012 LEAF, the RAF = 21.146 / 25.084 = 0.8430

                This is interesting as the on-board charger can have different efficiency depending if charged using 120V source or 220V source. (typically charging at 220V is more efficient as lower current and resistance for the same wattage). It does seem odd to me that the on-board charger is considered part of the drivetrain (battery, inverter, gearbox, and motor).

                Perplexed as J1634 accounts for AC (only) charger effienccy, but not the ReGen effienency of a PEVs drivetrain. Seems like PEV MPGe testing is not aligned to real-world engineering practices and technology in use. eg: the difference between regen being 90% vs. 60% effienent has a much greater impact on operational effience of a PEV that does a similar 60% vs 90% efficiency when AC charging. WTF?!

          3. ItsNotAboutTheMoney says:

            EPA estimated energy use is wall-to-wheel. Because of charging losses, the total amount of electricity need to charge is greater than the usable capacity. For example, I think the Volt is about 80% efficient when charging at 3.3kW.

            Since the EPA publishes separate efficiency ratings for city and highway, and combined ratings are calculated using 55% city and 45% highway, you can back-calculate the city and highway ranges using the relative efficiencies

      2. To be complete …

        Usable Battery Capacity: 22.68 kWh is based on the given EPA City Range (as city driving cycle is used to measure range) of 84 miles and the City efficiency of 0.27 kWh/mile.
        84.0 miles * 0.270 kWh/mile = 22.68 kWh

      3. To view EPA testing Drive Cycles (schedules) detailing speed vs. time for the various City, Highway, etc tests see:
        http://www.fueleconomy.gov/feg/fe_test_schedules.shtml

  7. DanCar says:

    Yes, range for 75 mph would be good.

    1. Aaron says:

      If you’re going that fast in an EV, you’re taking a HUGE range hit. Especially in today’s EVs (Model S excepted) because of sub-par aerodynamics. If I drive my i-MiEV at 75 MPH, I can watch the battery meter drop.

  8. Lad says:

    EPA seems to be in the test designing business; year to year the data means nothing because they keep changing the test.

    Put fully-charged BEVs on a standard dyno and run them at 35 mph, then 65 mph, until they hit limp mode. They could then factor in the aero and calculate the range at city and highway speed. That way a standard test that is not driver dependent, could be created and you would have a standard to compare against.

  9. GSP says:

    Great idea!

  10. Tesla Fan says:

    Ya and stop with the stupid MPGe crap that makes no sense

    1. MPGe is just an fictional unit, since defined as 33.7 kWh per MPGe, divide 33.7 by MPGe to get the a conversion in kWh/mile (or use 21.1 to get kWh/km).

    2. offib says:

      MPGe does matter, well at least it’s a good way of showing us what kind of car does better in which situation. It gives the idea of how much it would cost to charge too, but that’s what the window sticker and fueleconomy.gov is for where it tells you your annual cost and savings after 5 years.

  11. offib says:

    It’s pretty obvious. It would at least remind everyone that our mileage may vary.

  12. Lensman says:

    Well of course they should have different city/highway range ratings. Just like gas guzzlers have different city/highway MPG ratings.

    Better yet, they should have range ratings based on average driving speed of, say: 35, 45, 55, 65, 75 MPH. EVs lose a lot of range at higher speeds, and potential customers need to have a realistic idea of how far they can drive the car.

    While they’re at it, the EPA should revise the way MPG for gas guzzlers is figured, so their ratings are not almost universally inflated.

  13. Spec9 says:

    More information would always seem to be better.

  14. kdawg says:

    A couple other ideas.

    * A chart showing range based on outside temp

    * A 0-30mph time 🙂

  15. evnow says:

    EVs have large range variation based on speed and temperature. So, both need to be captured. In fact temperature variation may be bigger than city/highway.

    1. It is not typically the cold’s direct effect on the battery, as almost all electric car batteries are at least thermally managed with heating systems. It is the extra energy used to warm the battery, denser cold air and/or winter precipatipaton (which also affect gasoline car’s winter mpg ~12% negatively) For an electric, just these factors affect range 15-20% (for example my normally 50 mile EV range Volt estimates only 42 miles at ~30 degrees F) However use of the electric forced air heat (optional, if heated seats provide enough comfort) is an equal or even larger factor, as that alone can use battery energy that reduces range by another 15-20%. For example, at 26F I use this cabin heat for almost one hour and the EV range drops to ~30 mikes. So without using the heat (just heated seats) I can still average 20% over EPA (35 miles) but with the cabin heater use, it drops to 15% below EPA.

  16. Aaron says:

    I would be happy just to see realistic city ranges! My i-MiEV is rated at 112 MPGe. I regularly get 145 MPGe without hypermiling it, but driving in “B” mode.