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Help me with the math

Discussion in 'Gen 1 Prius Plug-in 2012-2015' started by Judgeless, Jan 28, 2011.

  1. sipnfuel

    sipnfuel New Member

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    0.34 kWhr per mile is off of the LEAF's EPA Window Sticker. I have to use this for my thumbnail calculations, because I don't have a LEAF or real-life data.

    I actually mainly did these calcs to find out the payback period on installing an Enginer system. It is useful to know the $ per kWhr so you can see if the Enginer system makes any sense at all.

    I read somewhere on this site that the Prius PHEV uses 0.24 kWhr per mile driven in EV mode. Don't quote me on that, but apparently Prius PHEV is that much more efficient as well.
     
  2. Judgeless

    Judgeless Senior Member

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    That is what I was looking for.

    My Nissan Leaf Forum • View topic - Electrical charging - measured results, 120v vs. 240v

    Using 240VAC it draws 16A max. This is in line with the number on the EPA sticker of 0.34 kWhr per mile. The posts claim that it draws a constant 16A. It never goes up or down.

    At my rate of .1139 per kWh it would cost me $3.84 for 100 miles for the Leaf.

    My Prius at 55MPG at $3 a gal would cost $5.45
    I would have to get 77MPG to make it even with today’s gas prices.

    Sipnfuel pays .1285 kWh at night and .31 kWh during the day
    At .1285 a kWh it would cost $4.39 at night (equal to getting 68 MPG in a Prius)
    At .31 a kWh it would cost $10.50 (equal to getting 30 MPG in a Prius)

    Tech_Guy pays .40 a kWh in CA
    At .40 a kWh it would cost $13.60 (equal to getting 23 MPG in a Prius)

    Electric companies are going to have to offer programs for people with EVs to make it comparable to hybrids.
     
  3. bisco

    bisco cookie crumbler

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    and what about in winter, and other conditions that cause the prius to get lower mpg and the leaf to go less than 100 miles on a charge. does that affect the comparison in any way?
     
  4. ETC(SS)

    ETC(SS) The OTHER One Percenter.....

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    That would depend on whether (and how much) temperatures will affect the amount of energy it takes for the LEAF to reach a full SOC, and how many miles you can travel afterwards.

    I've read data from the EPA that indicates that the 'real world' range for the LEAF is 73 miles. How they snapped the chalk line there is anybody's guess---and I would expect these data to vary wildly depending on the motives of the folks that are doing the measuring...just like the cost per mile.

    We'll just have to wait until there are more LEAFs cruising the highways and byways---and gather data.
    Like I said before, I applaud Nissan's efforts!

    However (comma) for me...it's just not an answer, but then neither is the Volt or Yota's PHV. I'm just reading and learning for now. If I ever get my fingers on a for-real plug-in, I'll let you know if I change my mind.

    I drove a G3 yeaterday for 134 miles and maintained 58.2 mpg. Gas is $2.78 this morning (still)......that's about 5 cents per mile, for a $22,000-$24,000 car.

    I can make that work for me for a while and let the science majors out there argue over PHVs/EVs. :cool:
     
  5. fuzzy1

    fuzzy1 Senior Member

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    I'm not seeing the claim that the current never goes down. And it doesn't square with a later post there:

    Based on other postings, this charging 'siesta' applies during a 100% charge, and current profile during an 80% charge remains TBD.
     
  6. cycledrum

    cycledrum PSOCSOASP

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    It wouldn't seem very feasible to rent a Leaf to try out for a week -

    It takes something like 20 hours to fully charge a Leaf on 110V. If you happened to have a level 2 charger, then you could juice it up in 8 hours, but I doubt you have one of those.

     
  7. cycledrum

    cycledrum PSOCSOASP

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    At the SF Auto show there were two PG&E reps talking about a service where you could get a seperate meter for the electric car, and IIRC, more of a flat rate. If PG&E has any brains, they will work with electric car owners, not gouge them for higher usage.

     
  8. fuzzy1

    fuzzy1 Senior Member

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    20 hours is for a fully discharged battery. If daily driving is about half its range or less, such a rental test should be feasible. It would still produce useful results about wallplug efficiency and charging current profile, and assist renters who don't have a 240V option.
     
  9. cycledrum

    cycledrum PSOCSOASP

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    Yeah, it's about 5 miles range / hour charge on 110V.

    Moot point though - I really don't think 'they' will be renting Leafs anytime soon. I would think too many people who are not familiar with the car might run it out of charge.

    Don't people who rent cars usually take it out on a trip? If so, the Leaf would be a terrible rental car. Recharge time not good for this scenario. I've heard debate that fast charging could shorten battery life, but not sure. Hopefully things get better, still, many can use a BEV. PHV is more promising for more people. Gotta walk before can run.

     
  10. cycledrum

    cycledrum PSOCSOASP

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    I think PHV's could offer an advantage if the price is right ....

    It's the short trips to the store that really kill fuel economy, even with a regular hybrid. I'm riding my bike more for 2 mile trips to avoid firing up this Accord.

    But, with PHV's, if they stay off gas on the 2 mile trips, which they should ... then no gas burned and you avoid the penalty of running on a cold ICE.

    So, the big question from me for the PHV is ........

    can you drive it very 'normally' with flow of traffic and not invoke the ICE at all? (of course assuming plenty range left).
     
  11. bisco

    bisco cookie crumbler

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    i could use an ev for 99% of my driving, as long as i kept it charged and ready at all times. most days it's 15-20 miles. a run to the cape in summer is 65 miles so, that might be iffy depending on state of charge. and i would need to be there long enough to charge it back up again to get home. i could probably work around trips like that, but the prius phev, volt or some other might be a better alternative. i s'pose by the time they are available for purchase, we'll have a better idea of operating parameters.:)
     
  12. uart

    uart Senior Member

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    I totally agree with this. The prius is already super efficient for longer trips. My wife in particular makes quite a few short trips (to the shops, to the hairdresser etc) and these are the real fuel economy killers. So yeah, even a short EV range would make quite a difference here.
     
  13. bisco

    bisco cookie crumbler

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    the engine having to warm up on short trips that probably won't use it is definately a bummer.:(
     
  14. uart

    uart Senior Member

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    Oh yeah that's a good point bisco, I was forgetting about that.

    Lets hope that in the final production model that they add a really good functional EV mode (eg EV button) to tell it that you intend to make a short trip on EV mode and to hold off the ICE unless it's completely unavoidable. (A bit like the present EV button but with a much more capable EV mode).
     
  15. bisco

    bisco cookie crumbler

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    +1 !!! ^:)
     
  16. sipnfuel

    sipnfuel New Member

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    I've done some more research on the matter as it relates to California

    The California Public Utilities Commission sets the highest rate of electricity at $0.31 per kWhr. You typically hit this Rate (Tier 5) if you are 200% above baseline for your designated area. In a Leaf, this is $0.1054 per mile in electricity. For comparison, in a Prius, you can drive $0.066 per mile using gasoline at $3.30 per gallon.

    The lowest you typically can pay for electricity in California is $0.11 per kWhr, and $0.14 - $0.18 is normal per kWhr.

    Basically, if you charge your EV everyday, you can expect to hit the highest tier. However, if you sign up for the CPUC "Time Of Use" program, you can get a fixed rate of approximately $0.15 - $0.17 per kWhr when you charge from 12:00 AM - 5:00 AM (or 6:00 AM in some areas).

    At $0.16 per kWhr, your cost per mile is $0.0544 per mile. Compared to a Prius at $0.066 per mile ($3.30 per gallon), this is 17.5% less in cost. For the same cost in fuel, you could drive 60 EV miles for 50 gasoline miles.

    The three large public utilities are Pacific Gas & Electric (N. CA), Southern California Edison, and San Diego Gas & Electric. Many small municipalities are independent and control their own rates.

    In California urban areas, we do not have much in wind resources. Roof installed Solar Panels systems are mainly what we can rely upon. If you had the money to install a $30,000 solar panel system, perhaps you can afford to go buy an EV :).

    Finally, you may ask yourself if you place a high value on energy independence. In California, > 95% of our fuel sources for electrical generation are domestic (or perhaps Nat Gas from Canada). You may decide if you would rather direct your dollars to countries and companies that have more of our national interests in mind.

    Still, about 60% of our electricity is generated from fossil fuels (Natural Gas & Coal), the rest is nuclear, hydro, and renewable & other. However, it is worth noting that most of our imported oil is not from the Middle East.
     
  17. macman408

    macman408 Electron Guidance Counselor

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    Not all of us have such high rates out here though... My municipal utility charges 8.8 cents per kWh. I also pay an extra penny and a half for 100% wind power. And even the peak time-of-day rate for over 300 kWh/month is only 11.5 cents/kWh...
     
  18. sipnfuel

    sipnfuel New Member

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    Wow nice. It's true some muncipalities control their own rates and that can be a great benefit to its residents. What portion of California do you happen to be from?
     
  19. sipnfuel

    sipnfuel New Member

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  20. pEEf

    pEEf Engineer - EV nut

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    Regardless of the present math, at some point (I happen to think soonish), Oil will be very expensive and electric is the future. It's easy to transport and covert, we just need to keep working on storage.

    Even if where you live, owning an EV is a break-even proposition, it's still worth doing. Not just for the environmental benefits either! If we buy more EV's, this will widen the battery market, and thus more money will be pumped into R&D and we will get better range. Also, the more EV's on the road, the more charging stations will appear, making range issues slightly less important. Buying an EV now with so-so range is like "priming the pump"! Your wallet vote will help the market grow!