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EREVs/EVERs (plug-in hybrids) vs EVs

Discussion in 'Electric Vehicles' started by Jay Cole, May 17, 2012.

  1. Jay Cole

    Jay Cole New Member

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    #1 Jay Cole, May 17, 2012
    Last edited by a moderator: May 19, 2012
    [moved from the Fisker Atlantic/Nina thread]

    Thanks for the welcomes, (=

    I agree with you Iz. I've always been of the opinion the the extended range model is at its zenith today. It will never make more sense than today. With each incremental improvement in battery tech, and as the price falls, the extended range model is eroded to some degree.

    However, I don't believe in our lifetimes, we will see gas being ignored by the masses...there will always be a need (and a subset) that will demand it, but over time, the sliver of the population that can get themselves into a BEV today, will expand fairly quickly. Maybe 5-7% by the end of the decade?

    That being said, the next 2-3 years will see little to no damage done to ICE vehicles by the BEV, much less the various extended range platforms. We are seeing the luxury/premium buyers trend into more things 'green', like hybrids, with some EREV/BEV demand, but there is a long, long way to go. I think the second wave/2nd gen of battery tech will be the first real salvo into the regular mass market of petrol cars (and by association, the EREV platform) .

    Right now, BEVs/EREVs only 'sorta' make sense to maybe a third of the luxury car buying population (much less for entry level/middle class demo) , thats a long way from serious market penetration...now if you can double up on the range and hold pricing in place against inflation over the next 5-7 years, then its a different game.
     
  2. vfx

    vfx Well-Known Member

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    I always compare the EREVs to those combo VHS/DVD machines. Just the hybrid some people needed to buy at the time.

    It's time to buy a new video machine. With a shelf-full of VHS tapes (gasoline stations) and a interest in DVD's new better technology (EVs) the answer is buy both until next round of buying.
     
  3. SoCalGuy

    SoCalGuy Member

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    Still a niche for the range extended EVs

    I'm not so sure that we're necessarily at the peak yet of the EREV/EVER/PHEV. If someone comes out with a highly efficient, purpose-built, gas-based range extender, that will prolong the life (and increase the interest) in range-extended EVs. Consider this:

    -> 1 gallon of gas has approximately 33 kwh of energy and weighs 6 lbs or so
    -> A 33 kwh battery weighs approximately 900lbs in the case of the Fisker or 500lbs in the case of Tesla Model S

    High end of current ICE efficiencies are around 30% or so (60% lost as heat/exhaust, 10% as combustion/friction/pumping), so in that gallon of gas, you're getting a usable 10 kwh per gallon, or roughly 1.7 kwh per lb. That still compares favorably with batteries which are more like 0.04-0.07 kwh/lb. Theoretically, even with the current ICEs on the market, you could do away with the battery entirely and just mate the ICE to a generator and have that power flow go directly into the electric motors (quickaside: I wonder how that would improve the Fisker Karma - getting rid of 606lbs of weight or roughly 11% of its weight should improve fuel efficiency and acceleration times... they could replace the 20kwh battery with an additional 2 gallons of gasoline and save almost 600lbs!... )... To optimize efficiency for the ICE, you'd need some energy reservoir (maybe a small battery or super capacitor) that could act as a buffer during start/stop actions as well as during modes of generation surplus. A gas-based range extender would likely run at one single RPM level where its efficiency would be highest and thus, on low load applications like highway cruising, store the extra power generated into a small battery which would then alternate with the ICE to provide variable power to the electric motors.

    That as a long aside, but my main point is that batteries have a long way to go in the way of improving energy density vis a vis gas. If we could double the efficiency of gas-based range extenders, it would reduce the need for high-capacity batteries and still provide many of the benefits of the EV (imagine if you could get 20 kwh of usable energy in just 1 gallon, 6 lbs of gas - that would provide a fuel economy of 71 mpg for the Model S [20 kwh * 300/85 = 70.6], and likely much more than that if you can reduce the 1200 lbs of batteries into maybe a small 150 lb battery/capactior and a 300lb range extender and fuel tank).
     
  4. spatterso911

    spatterso911 MSP#7577 **--** MX#1891

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    There are still a few options for the EREV market, including use of high efficiency diesel engines, more compact battery technology with greater effective range and more efficient charging from the generator. The ideal EREV would get about 100 miles from the battery alone and about 350 or so from the generator.
     
  5. Dan5

    Dan5 Member

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    You are confusing the issues and weights. if you want to get really technical about it, the "fuel" for an EV is electrons which have a negligible weight, carrying around a large battery is no different than carrying around a car engine

    What you should really consider is the propulsion systems

    The propulsion system for an EV is battery (500 lbs) + motors (about 125-200 lbs) + inverter (25-50 lbs)

    Best case scenario for the Model S
    33/85 *1000 = 388 (battery) + about 200 lbs (motor + inverter+ wires); say 600 lbs total

    Normal car engine
    Typical engine is around 600 lbs + 6 gallons of gas + 10 lb gas tank + 5 lbs for misc components = about 630 lbs

    We can say everything else is "similar", transmission, AC, heater, interior, etc should weigh about the same- we all know that there's more crap on an ICE engine though, and EVEN more on a PHEV, but for simple calculations it suffices

    And actually the Model S gets over 100 mpge

    300 miles/85 (kwhr) *33.4 (kwhr/gal) = 117 mpge
     
  6. SoCalGuy

    SoCalGuy Member

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    I think the N20 by BMW weighs around 325lbs and fuel in an ICE car is still electrons as well - the difference is the chemistry in which these electrons are stored (gas vs. li-ion batteries), but I digress. The main point is that the energy storage mechanisms in EVs are clunky compared to the chemical energy storage in a conventional ICE. If you can marry the benefits of high energy density (e.g. ICE paradigm) with the benefits of an low/no emissions, durability, efficiency (e.g. EV), then you have the best of both. The key to unlocking this will be designing an engine that is optimal for converting energy in the form of gasoline into energy in the form of electricity. Taking an off-the-shelf, designed-for-mechanical-energy-conversion ICE and stapling it onto a generator is not the most technically efficient way to do so - its a 'hack' of sorts.
     
  7. ckessel

    ckessel Active Member

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    The EV-ER market segment mostly confuses me. If gas is relatively cheap, you never make back the surcharge for the EV part. If gas gets really expensive, you'd be best off ditching the ICE and getting a bigger battery EV. The only way the ER part seems to make any sense is in a particular gas price range where you could make back the surcharge, but gas isn't so expensive that you care all that much if you mostly run on gas (e.g. longer trips).
     
  8. qwk

    qwk Model S P2681

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    Exactly. It makes no sense. You still have to buy gas and change the oil, plugs etc., while paying a premium for the hybrid part.
     
  9. EVNow

    EVNow Active Member

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    It makes eminent sense. Ideally I'd like to have an EV & a PHEV/EREV. That way all our daily & in city travel is electric and we would still have a vehicle for the long distance. With this combination I can cut down my oil usage by more than 90%.

    An EREV also makes sense as the only car.
     
  10. I would venture a guess that most people who purchase EV"s at this point are not making the purchase mainly based on gas prices....
     
  11. ckessel

    ckessel Active Member

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    I can't speak for others, but it's a big factor for me. I wouldn't be buying the Model S if I wasn't going to save a bunch on fuel. Though I live in a state with incredibly cheap nighttime electricity rates.
     
  12. SoCalGuy

    SoCalGuy Member

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    People aren't buying the Model S because it pays for itself with the gas savings - they're buying it to make a statement. If you wanted an energy efficient car, Corollas, Pruises and Civic Hs make a lot more economic sense.
     
  13. ckessel

    ckessel Active Member

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    I never bought a car, or even remotely considered buying a car, to make a statement. I buy a car because it's something I'll enjoy driving and owning for the price I'm willing to pay. Without the gas savings, the Model S would fail to pass the "willing to pay" calculation of total cost of ownership.
     
  14. AnOutsider

    AnOutsider S532 # XS27

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    I think (especially around here), you'll find a third group that doesn't lean so much on the environmental as the cool tech and performance factors.
     
  15. Lloyd

    Lloyd Active Member

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    There is also the group that does not like the US to be dependent on foreign oil. If there were a problem with getting oil out of the middle east of which there are many scenerios that could instigate an issue, it would make the gas lines of the 70's look very small in comparison. Electricity at some time may be more plentiful and available than gasoline.
     
  16. vfx

    vfx Well-Known Member

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    [FONT=&quot]Coda quote about EV buyers: [/FONT]
    [FONT=&quot]Hausch said the EV market is divided roughly into four consumersegments: geeks, greens, gloaters and grazers.[/FONT]
    [FONT=&quot]Geeks are early adopters who love electric vehicle technology,while
    greens are environmentally aware consumers who want to reduce theircarbon footprint.[/FONT]

    [FONT=Verdana, sans-serif]Gloaters are vehicle enthusiasts who care a lot about design, and[/FONT]
    [FONT=Verdana, sans-serif]grazers are cost-conscious people who count every penny spent on gas, smogchecks and oil changes, costs that the Coda comes without.[/FONT]

    [FONT=Verdana, sans-serif]I would add there are people who don't care what other people think. If the car is right it does not matter to people who "think different. Keeping with the (lame) "G" theme call them the Gypsies[/FONT]

    [FONT=Verdana, sans-serif]Add the national security reasons too. The generals? The guns?[/FONT][FONT=Verdana, sans-serif][/FONT]
     
  17. Tommy

    Tommy Member

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    #17 Tommy, May 17, 2012
    Last edited: May 17, 2012
    And may I add the Grinners (again keeping with the "G" theme); those that buy a car for the fun of the driving experience which the Model S should have in spades and hopefully also the Fisker Atlantic. The nice part about this group of people is their purchase is not based on politics or any belief system per say; who can argue with you when you say you bought the car because of the "fun factor".
     

  18. Electricity has always been more plentiful and more available than gasoline?
     
  19. SByer

    SByer '08 #383

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    Nope. Things might have gone very different in the early days of the automobile had the electrification of America been further along.

    As for hybrids, yes, for a time they may make sense, but only if out-of-the-box gas-to-electricity conversion schemes are considered and made economically and commercially viable. Say, something like a free piston engine (which could have a high conversion efficiency if tuned).

    As crappy as ICE torque curves are, some of the ICE alternatives are even worse - but a hybrid model can divorce that requirement. The ICE and it's pathetic conversion efficiency just need to die already.


    As for Fisker, I still wonder what the heck they bring to the table. They really need to develop battery, motor, or controller tech in-house. Exterior design isn't a sustainable margin support. The current crappy parts they are putting into the Karma are kinda shameful. Where's the value add? I suspect they've hired enough talented engineering that they could get somewhere, and removing Henrik from the helm certainly helps. (Good engineers and good designers both defer the appropriate parts of a project to each other, Fisker didn't seem to be able to, or at least overrode engineering requirements with design dictates).
     
  20. Electricity in general is far more accessible and ubiquitous than gasoline, maybe you are talking about charging stations vs gasoline pumps?



    If one was in the market for a premium 4 seat vehicle but did not want to put up with the hassle of plugging in and waiting, the Karma makes sense. The Karma combined EV + Gasoline gets better MPG than most any other car in its class. Plugging in everyday and having to worry about charging, and planning to stop at RV parks for a few hours is not something most people are willing to put up with. I probably would select the Karma over a pure EV (if I only had 1 vehicle), from a pure convenience factor the ability to drive a significant distance on EV only distance (daily) but also the flexibility to drive longer distances without planning several stop overs and waiting, is a pretty significant advantage over a Pure EV. The quality of materials used on the interior of the Karma (minus the buggy control center) blows away the Model S (this is from someone who has a Model S Performance on order). There are far more vehicles that are sold by other manufacturers that make a lot less sense than the Karma...Cayenne Hybrid, GL Hybrid, Escalade Hybrid etc.

    Fisker developed & patented its EVer powertrain so there is value there. Generator -> Battery technology.
     

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