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Traded in the PIP for a new 2014 Volt...

Discussion in 'Gen 1 Prius Plug-in 2012-2015' started by ny_rob, Mar 22, 2014.

  1. ny_rob

    ny_rob Senior Member

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    It 's impossible and inaccurate to use just one number or even two numbers to quantify efficiency in hybrid vehicles because of the number of modes these vehicles now use for propulsion.
    Pure EV's like the Leaf and Tessla are simple- mi/kW and total range under a std (simulated) course like the EPA currently uses is good enough. Once you go over to hybrid vehicles you have EV mode, ICE only mode, and HV mode that blends both power sources. You'd really need three sets of figures- mi/kW for EV mode, mpg for ICE mode, then some kind of figure that represents HV mode efficiency?

    The window sticker on my 2014 Volt shows 98MPGe, and 37MPG- as I mentioned above, I've driven 900 mi so far and used 0.6 gal of gas which works out to 1,500MPG . Clearly the current system doesn't work....
     
  2. inferno

    inferno Senior Member

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    Could be a marketing thing.

    We are used to seeing Miles per Whatever.

    Seeing a car say 300 Wh/Mile next to a sticker that says 100 mpge would definitely need a double take!
     
  3. jdk2

    jdk2 Active Member

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    Do you think, given your commute, you may never need gas for as long as you own the car?
     
  4. ny_rob

    ny_rob Senior Member

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    Since the vehicle manufacturers list usable kWh capacity of their batteries it's easy to derive accurate range predictions based on published mi/kW efficiency.
    Vehicle "A" gets 3.4 mi/kw and has 10kWh usable battery = 34 mi EV range
    Vehicle "B" gets 3.7 mi/kw and has 10kWh usable battery = 37 mi EV range
    From what I've read- most current EV's get between 3 and 4 mi/kW so there's not a big gap in efficiency like there is in ICE vehicles (comparing a Yukon to a Fiesta), but once you know it's efficiency spec and it's usable battery capacity- now you get the all important EV range prediction result.
     
  5. inferno

    inferno Senior Member

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    BTW...Talk about KWh per 100 miles which the epa has a pretty "good" rating (a rating that's albeit available).

    The Prius is 29 KWh/100 miles
    The Volt is 35 KWh/100 miles
    The Energi Fusion is 34 KWh/100 miles
    Tesla is 38 KWh/100 miles

    So this is very interesting! The Prius is the most efficient of the bunch. So to match the Volt they don't need as large of a battery. What I would like to see Toyota do to stay ahead of the competition is match the current Volt's range (GM is about to find a way to put that 5th seat back in so Toyota must be able to somehow do that), but have an EV Power mode. One of the greatest things about the Gen III Prius is the Power Mode which is sufficient enough and doesn't act like the stereotypical Prius. That would satisfied all worlds.

    And of course let the Plugin not lose it's overall range (whereas the Volt is like 300 straight, the Prius would hopefully keep it's 500+ range with more batteries). Then we would have a winner. And **that's** what the automakers should be touting their numbers as. Of course it's a bit backwards because mpg you want higher, KWh/100 miles you want lower...

    Tesla is also going to improve their efficiency as well. Glad to see the Prius is on top though even if it's a minuscule amount of energy.

    Let the competition heat up, so many choices! Tesla though of course is difference since it's pure battery, though the 85 KWh version supposedly has a 265 mile range which is close to the Volt.
     
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  6. fotomoto

    fotomoto Senior Member

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    But at what speed(s)? This kind of goes back to the ongoing disgust at the EPA's highway rating system.
     
  7. ny_rob

    ny_rob Senior Member

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    Very possible!
    If I get ICE'd at work I'd need to burn some gas for the trip back home- but I haven't got ICE'd a long time- so I'll keep my fingers crossed ;)

    The Volt's computer will run the ICE for a few min every six weeks to keep it lubed properly, and it will also run the ICE every six months (not quite 100% sure about that time period) to burn off some gas so you can add fresh 91 octane gas into the tank to keep it from going stale. So even if I never had the need to burn gas- the Volt will still burn (under 10 gal/year ?) just for maintenance.

    FWIW- this morning after a full charge my EV range estimate was up to 46 miles!

    Exactly!
    They need to make a meaningful simulation for EV's and stick with it- the old simulation for ICE vehicles doesn't work for EV's and hybrids. There are people on other forums that love to quote the EPA's "6 mi" EV range figure for the PIP as it's normal EV range.
     
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  8. Zythryn

    Zythryn Senior Member

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    I agree completely with your first statement.
    As for the latter, you are comparing mpg to MPGe which can only be done, and will give you a much better result, if you include the electricity you have used.
    You can't blame a screwdriver for being a lousy tool because you are trying to hammer a nail.
     
  9. fortytwok

    fortytwok Active Member

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    "Very possible!
    If I get ICE'd at work I'd need to burn some gas for the trip back home- but I haven't got ICE'd a long time- so I'll keep my fingers crossed ;)

    The Volt's computer will run the ICE for a few min every six weeks to keep it lubed properly, and it will also run the ICE every six months (not quite 100% sure about that time period) to burn off some gas so you can add fresh 91 octane gas into the tank to keep it from going stale. So even if I never had the need to burn gas- the Volt will still burn (under 10 gal/year ?) just for maintenance."
    Does a Volt have the same requirement as a PiP to replace 50% of the gas every 6 months ?
     
  10. fotomoto

    fotomoto Senior Member

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    Basically yes. GM recommends keeping about 1/3 of a tank for folks with very high % EV ratios. My Energi also has a fuel maintenance mode so being that I'm at 90+ EV ratio I'm planning to keep 3 gallons in mine ($10 "fill ups"!!!) for the occasional short out of town trips I make.
     
  11. Jeff N

    Jeff N The answer is 0042

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    However gasoline is used to power 1/3 of the miles driven by all of the Volt on the road, according to OnStar's periodic PR updates. That tells me that the hybrid mode mpg of the Volt is important and that, while adequate, it needs to be improved.

    The Prius is not really 29 kWh/100 miles because that EPA estimate includes burning a small amount of gasoline. If you make an effort to back out the gasoline part of that the result is probably around 32 kWh/100 miles although there is no precise way to do that calculation.

    If you then add more heavy batteries to increase the EV range of the Prius that will tend to drop the efficiency a bit. It's a tradeoff and so there is no perfect answer for everyone. That's why it is good to have multiple cars on the market with different design points.
     
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  12. john1701a

    john1701a Prius Guru

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    Dividing kWh of electricity consumed (including charge loss) by EV miles gives good measure, especially when real-world data is used.

    Here's mine...
    [​IMG]

    (3,415 / 12,333) * 100 = 27.7

    The electric motor is surprisingly efficient.
     
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  13. Jeff N

    Jeff N The answer is 0042

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    Here's my monthly OnStar email report that I received 2 days ago that is based on my 6 day a week 100+ mile roundtrip commute. As an aside, I just passed 50,000 miles on grid EV charging and have 77,300 miles overall after 3 years and 3 months (not quite the 143,000 miles another owner has on his car...).

    Although not directly shown in the OnStar report, you can also derive:

    525 kWh Electricity (inc. charging loss)
    23.3 gallons of gasoline
    45.6 mpg hybrid mode
    75.5 MPGe combined gas & electric

    image.jpg
     
  14. ny_rob

    ny_rob Senior Member

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    Jeff...
    I haven't gotten a monthly report yet.
    I bought the Volt on March 16th, should I expect the report April 16 or so?
     
  15. markabele

    markabele owner of PiP, then Leaf, then Model 3

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    Earlier someone mentioned that the larger the battery pack the less the MPG's matter. This is only true on a case by case basis. Someone that takes many road trips or has a super long commute would definitely care what kind of MPG they get.
     
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  16. fortytwok

    fortytwok Active Member

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    Dividing kWh of electricity consumed (including charge loss) by EV miles gives good measure, especially when real-world data is used.​

    Here's mine...​
    [​IMG]

    (3,415 / 12,333) * 100 = 27.7 The electric motor is surprisingly efficient.​
    -----------------------------------
    ok John - what am I doing wrong here ? my kWh / 100 miles is coming out way low compared to yours

    10602 EV miles
    1145 HV miles - 22 gallons - 52 mpg HV 534 mpg overall
    2069 kWh - not sure how you calc'd charging loss but if I multiply as you did then I get 2435 / 10602 = 22.9

    Edit - Doh ! I just figured out low is good !
     
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  17. Zythryn

    Zythryn Senior Member

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    To individuals, sure. But in general, the more batteries, the less mpg matters.

    If you take 100 people and give them all 5 miles of EV range, the mpg matters a lot as most will be using gas for much of their trips.
    If you give them all 90 miles of EV range, mpg matters much less as a group. Because even if you have one driver that drives 150 miles a day, you have 90 that will use no gasoline.

    For those 90, they could care less if the gas engine got 75 mpg or 2 mpg.
     
  18. telmo744

    telmo744 HSD fanatic

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    for fortytwok - Nothing wrong, probably you are driving your PiP in a better/efficient way... ;)

    I've met someone that squeezed 30km+ in EV out of a european test fleet PiP, while my driving got 25km only, and Iway babying it...
     
  19. markabele

    markabele owner of PiP, then Leaf, then Model 3

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    Very true. So you are saying that hopefully they didn't spend too much on R and D for the ICE on the Volt 2.0 if the pack truly is larger as proclaimed? ;)

    Lots of choices for lots of situations. That's the great things about the time we are living in.

    This is the graph people need to look at when deciding between a Volt and PiP.
    [​IMG]
     
  20. Zythryn

    Zythryn Senior Member

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    I'm hoping they spent some effort as that is the weakest point of the drivetrain.
    However, if the EV range was only 20 miles, then I would say good mpg of the gas engine is much more critical.
    It is still important, just not AS important. All a matter of finding the right balance.

    Perhaps it would be more useful if the pricing assumptions were listed.
    It is a great idea, but the calculation changes for every utility, every various program each utility has (i.e. TOU, tiered, flat rate, etc) and fluctuates day to day with local gas prices.