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How is EV mileage determined

Discussion in 'Prime Fuel Economy & EV Range' started by Oskar, Jun 22, 2023.

  1. Oskar

    Oskar Member

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    I've been curious about this every since I got my 2020 Prius Limited. In the summer I can get about 36 miles of EV charge. But, I know that if I get on the highway and zoom along at 70mph those 36 miles may end up being 18 miles. On the other hand, if I drive to the next town averaging 25 mpg (stop and go traffic) I can stretch the 36 miles by a few more miles.
    I know all-electric cars can give you about 250 miles on a change, but only if it's driven under certain conditions.

    So, my question is at what speed/conditions is the initial charge of 36 miles determined.
     
  2. Salamander_King

    Salamander_King Senior Member

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    It's called Guess-o-meter or GOM for short. The range is just an estimation based on your recent EV drivings and present conditions such as HVAC settings and ambient temp.

    It offers a very poor prediction capability unless you drive very similarly as you did in the past.
     
  3. john1701a

    john1701a Prius Guru

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    It really isn't any different than mile estimates based on MPG... speed, traffic, temperature, wind, etc. When you have a plug-in hybrid, focus tends to be on distance. The reason why is simple, you want to get the most out of the capacity available.

    Having recently switched from a Prius Prime to a bZ4X, it's easy to see value of mi/kWh and how most BEV enthusiasts have been neglecting it. When you have so much more capacity available, distance becomes a badge of honor rather than a practical measure. Heck, even when driving on a road trip, that mi/kWh is more informative than a miles estimate.

    I'm seeing around a 3.5 mi/kWh average with my wide variety of summer driving. From the 64 kWh of usable capacity, that's almost dead on with the EPA estimate. It calculates to 224 miles. Watching the value tease 5 mi/kWh at times is very rewarding. Watching it drop in the winter will be very informative, especially when exploiting the infrared-heater and with pre-conditioning.
     
  4. bisco

    bisco cookie crumbler

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    it uses proprietary software algorithms to determine the estimated range. because my ev driving is so similar day in and day out, my range estimate only changes with the climate.
     
  5. Oskar

    Oskar Member

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    Appreciate the responses, and they make sense to me. However, when I bought my Prime the sticker said something like 135mpg avg. I'm wondering how they got to that figure. From the responses I assume they used an average mph speed to arrive at that.
     
  6. Salamander_King

    Salamander_King Senior Member

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    Screenshot_20230622-155924.jpeg PP has EPA rated 133 mpge. Notice the "e" on the end. This is gasoline equivalent fuel efficiency for EV using battery. It just is another way of expressing how efficient the EV is. The conversion is 133 MPGe = 3.946002 mi/kWh. So just like EPA rated MPG for gas engines, under EPA testing condition, PP run at this efficiency.

    And remember that just like a gas engine MPG rating, your e-mileage may vary. It is just a bench mark. My life time efficiency on 2021 PP was 5.2miles/kWh. That's 175MPGe. But there are people who got much less than rated 133MPGe.
     
    #6 Salamander_King, Jun 22, 2023
    Last edited: Jun 22, 2023
  7. Trollbait

    Trollbait It's a D&D thing

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    The mpge or kWh/100 miles figure on the window sticker is figured out the same way as the mpg one for ICE cars, with the car in a lab running the EPA test cycles.

    https://www.fueleconomy.gov/feg/fe_test_schedules.shtml
     
  8. Oskar

    Oskar Member

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    I guess this is what I was looking for, thanks. Was always curious on how they arrived at the "average" figure.
     
  9. bisco

    bisco cookie crumbler

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    Don’t confuse mpg with mpge. It’s a useless number except for comparing models
     
    Oskar likes this.
  10. Jake Armitage

    Jake Armitage New Member

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    I'm not sure how it's determined, but it might not be so accurate. On a Prius Prime 2023 SE, my EV estimations come to about 37 miles, but I've routinely been able to squeeze about 10 more miles out of it every time, without thinking about driving economically. I'm sure if I tried, I can get a few more.
     
  11. Salamander_King

    Salamander_King Senior Member

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    The EV range Toyota publish is under very strict EPA testing parameter. Your driving condition may differ drastically from the testing. That being said, in my experience with previous PP models, it was easy to beat the EPA EV range of 25 miles. I routinely got ~35 miles of EV range in the summertime. I think your 23 PP is similar. But, be warned that the EV range will drop in winter. NJ is not very cold as my local, but it will drop substantially from the summertime high. In my climate, I got a winter low range of 18 miles which is almost half of the summertime high of 36 miles. So, on average 25 miles of EV range was quite accurate for me.