MPG in Hybrid Mode

Discussion in 'Prime Technical Discussion' started by CEJ, May 13, 2019.

  1. CEJ

    CEJ Member

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    So, it seems fair to assume that if one travels in HV mode with non-zero SOC (either 100% or less), which we agree will not fluctuate much from its initial percentage (at least on longer trips), that the mpg reading (having been reset at the start) on the main display should be fairly accurate--about as accurate as the reading would be traveling with 0% SOC (which was discussed earlier).
     
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  2. jb in NE

    jb in NE Senior Member

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    Exactly correct.
     
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  3. jerrymildred

    jerrymildred Senior Member

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    Agreed. There will be minor variations because the system may be either replenishing or using the battery when you stop, but it's minor and it averages out.
     
  4. CEJ

    CEJ Member

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    Can you explain this in a bit more detail?
     
  5. Tideland Prius

    Tideland Prius Moderator of the North
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    Well the idea is that you’re charging at home so isn’t it best if you got home close to empty? That would mean you maximized the use of the EV driving range to reduce your gasoline usage.
     
  6. Blue-Adept

    Blue-Adept Active Member

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    Here is how I see it. I use all battery in the first 25 miles of my 65 mile commute to the family cottage. Then do the remainder in HV mode. Average 112 mpg summer to 96 mpg winter for the trip. If I do all HV at 60 mph. In HV mode the engine turns on and off as needed. This is at about 65 mpg. By running EV down to 0% then HV with one warm up cycle the car optimal for HV mode.

    Is my logic incorrect?

    May need more Beer
     
  7. Blauer Glimmer

    Blauer Glimmer Active Member

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    You might do a little better if you use EV for local streets and HV for highway speeds.
     
  8. CEJ

    CEJ Member

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    Yep. Makes perfect sense. Thanks!
     
  9. Salamander_King

    Salamander_King Senior Member

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    Off course, for many of PRIME drivers, using up EV range charged from the wall is more economical than burning gasoline. For me, I do it purely for ecological reason for EV drive from the wall cost more than HV drive from the gas station.
     
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  10. Tideland Prius

    Tideland Prius Moderator of the North
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    :( Canada Day means new taxes added to the fuel cost so our gas prices went up. All the more reason to stay in EV (that and it drives much nicer in EV Mode)
     
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  11. Salamander_King

    Salamander_King Senior Member

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    I am one of very few drivers who is wishing the gas price would go up more. lol When the gas price hit $3/gal, I feel very satisfied driving all the way to work and back to home on EV 38 miles.
     
  12. CEJ

    CEJ Member

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    Curious to know what the cost is per KWH where you are.
     
  13. Tideland Prius

    Tideland Prius Moderator of the North
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    It's about US$4.20/gal here... while electricity is US$0.08/kWh (usage only... not including basic fees which you would pay regardless of whether you have an electric car or not)... you can see why it's appealing (Although I'm still surprised it's not more popular... We have a decent number of DCFC's that are spaced out along highway rest stops and within cities to support road trips). Within town, most J1772 stations that aren't at hotels, are usually free to charge.

    The recent federal tax rebate here that is stackable with provincial rebates did help sales. There's a definite surge in Model 3s (the only one that is delivering at a decent pace) around town. Primes are also noticeable as are Niro EVs and PHEVs. The rest are trickling in as stock is in insanely short supply.

    The nice thing is that all incentives are point of sale rebates (both federal, and provincial where applicable) so it's not contingent on your income tax as it is in the US.
     
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  14. Salamander_King

    Salamander_King Senior Member

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    Our current electricity rate is $0.195/kWh. Gas on the other hand has been less than $2.50/gal. The cost of electricity I calculate includes everything I pay for the electricity from the grid. Supply, distribution, tax, fees, and renewable energy surcharge are all included in this figure. I have paid as high as $0.275/kWh in the past when I picked a wrong supplier. Here is my electric cost in last 10 years. Red is mine, Blue is the national average in the US.

    electric rate national average vs actual.png
     
    #254 Salamander_King, Jul 3, 2019
    Last edited: Jul 3, 2019
  15. Tideland Prius

    Tideland Prius Moderator of the North
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    :(

    If I include fees, it'll be significantly higher since our basic fees are higher than the US (lower population, cost of infrastructure spread out over fewer people = higher cost per person). Basic fees is 21 cents per day. There's also a regional transit levy of 6 cents/day and a customer crisis fund of less than a penny a day (basically if you happen to lose your job and can't pay the bill for that cycle, they can help you out).

    And since I'm looking at my bill, electricity is actually US$0.07/kWh not 0.08.
     
  16. Salamander_King

    Salamander_King Senior Member

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    Is your electricity highly regulated? I have never heard electricity fee being charged per day, but I guess, "per day" means fixed amount every month divided by ~30 isn't it? Some published "electricity rates" are just for the supply part I think. Some may also include supply and distribution, but my electricity rate is all tied to amount of kWh used. No fixed fees.

    Fixed fee or not, my take is that unless you pay the rest of "fees", "taxes", "premium" and such, you are not going to get any of your light bulb lit in your house. So to be accurate, true number of electricity rate should be what is paid for that month divided by the total amount of kWh used for that month. As you can see, in my graph, even though I have a fixed "rate" for given calendar year, except 13-14 when I contracted with a supplier who offered me initial 6 mo of low fixed rate and following 6 mo of variable rate, my actual cost/kWh fluctuate month to month. What I am not sure is that whither this monthly fluctuation is unique to unregulated states or not. We are unregulated states which allows consumer to pick and choose electric supplier.
     
    #256 Salamander_King, Jul 3, 2019
    Last edited: Jul 3, 2019
  17. Tideland Prius

    Tideland Prius Moderator of the North
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    Basic fees are for transmission, maintenance, upgrades etc. Usage is per kWh.
     
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  18. CEJ

    CEJ Member

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    Cost here in winter (Oct 1-May 31) is $.0548/kwh and $.08/kwh during the summer. Gas is like $2.80 or so per gallon. I roughly estimate my cost is (during the winter) 1/4 to 1/5 in EV compared to what it is in HV.
     
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  19. Salamander_King

    Salamander_King Senior Member

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    Well, if you use average electricity rate for whole year $0.0674, your full charge cost is $0.0674/kWh * 6.3kWh = $0.425 for average 25 miles of EV range. You cost per mile is $0.425/25 = $0.0169/mile
    For HV, 1 gallon of gas at $2.80/gal for average 54 mpg would give you $2.8/54 = $0.0518/mile

    So, the cost difference is more like 1/3 (0.0169/0.0518 = 0.326)

    Of course your MMV, the calculation is based on EPA rating for EV range and HV mileage.

    Also if you have electric bills handy, hand calculate your real rate by dividing the total amount paid in a month by the kWh used for the billing period. You maybe surprised to find our you are paying more than utility published fixed rate.
     
  20. CEJ

    CEJ Member

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    Yeah. I was just interested in the relative cost during the spring when the car was new. (Actually, one wouldn't use $0.0674 for the yearly average, but something like $0.0632 since the higher summer rate only applies for only 4 months out of the year.) At the time I figured it, I was consistently getting 30mi or more EV range. My wall meter says it takes about 6.6 Kwh to fully charge. So EVcost/mile=6.6x.0548/30 =$0.012/mi and for HV 2.80/54=$.05184/mi and the ratio of EV/HV cost is 0.23 about 1/4. Actually, at that time, I think gas was closer to $3.00/gal, making the cost ratio .214, closer to1/5. Now I am getting EV ranges of 38-39 but the higher rate of $0.08 just went into effect, which gives a ratio of 0.267 (and a week ago when the old rate still in effect, it would have been .0183).

    I am not inclined to include the usual fees on my bill in the calculation because they are a flat rate (not proportional to usage) and would be the same whether I was charging the car or not. The sales tax (a few dollars), which is, of course, proportional to usage, would change things somewhat but I didn't try to include that.

    Pretty darn economical anyway you scratch it!

    BTW, what is MMV?
     
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