Cost to Charge at Home

Discussion in 'Clarity' started by RickSE, Sep 3, 2018.

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  1. RickSE

    RickSE Active Member

    I’m living in Massachusetts using Eversource. Our electric rate is about 12.5¢ per kw plus a disribution fee of around 8¢ per kw. So it looks like we pay ~21¢ per kw. Doing the math says it costs (12.5 + 8) x 17 = $3.50 to go 47 miles. I get 34 highway in my accord and pay $2.80 per gallon. 47/34*$2.80 = $3.87. What am I doing wrong here since the distribution is based on usage?
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  3. Kendalf

    Kendalf Active Member

    You won't actually use 17kWh for a full recharge. A full recharge from 0 range to 100% will use about 15kWh (depending on EVSE efficiency because there is a budget in place for battery longevity reasons.
  4. jorgie393

    jorgie393 Well-Known Member

    I’m in Mass. also. Two minor corrections: the electrical “fillup” on the Clarity is not the whole 17kwh of the battery. It is only about 14.1 kwh (the battery has some cushion top and bottom to prevent bad battery life--this is a real # based on what I have seen from my EVSE). So your charge is (12.5 + 8) x 14 = $2.87.

    The other piece is that your Accord (and I just had one) is 34mpg highway, but you probably don't drive it 100% on the highway unless you live and work on exit ramps. So my guess is that, like me, you get more like 28 total average mpg based on the real-world use. I won't do the math since it's just a guesstimate, but the Accord costs more that you calculated.

    Our electricity is relatively expensive, and gas is not so expensive, in this state so you and I don't see huge cost savings, but there is some. We can still feel good about it, esp. financially when gas spikes again.
    Kendalf likes this.
  5. KentuckyKen

    KentuckyKen Well-Known Member

    The most anyone has reported pulling from their EVSE is 14.4 kW from the wall. With a charger efficiency of, say, 90%, then only less than 13 kW is available for use which gives about 4 kW split between the top and bottom buffer. But of course you pay for the 14.4 kW it took to charge a fully depleted battery (0% usable charge and 2 bars).
    The EPA/DOT portion of the Mulroney sticker uses 31 kW per 100 miles. FWIW, I’m only using around 24 kW to go 100 miles with ac on, single passenger, 75/25 city/hwy, speed limit 55 mph. Of course that will not be as good in the winter time or if I were going 70+ mph.
  6. jdonalds

    jdonalds Well-Known Member

    Our JuiceBox Pro 40 keeps records of every charge. We've only ever charged at home so the records are as accurate as can be I guess.

    The longest charge time has been 2 hours 10 minutes. The charge consisted of 14.318 kWh.

    Our local electric supplier charges $0.15 / kWh so a full charge is $2.14, for about 47 miles.
    Our cheap local gas today is $3.36. To be extremely lazy I'll use 47 mpg running in HV mode. So savings per 47 miles by running in EV mode are $3.36 minus $2.14 = $1.22.

    We are at a run rate of 20,000 miles per year. Divided by 47 = 425 gallons or full charges. Annual savings of $519. However...

    We have a solar system that supplies pretty much all the power the house needs, and there is usually enough solar energy left over to also charge the car. So our real savings is more like 425 gallons * $3.36 or $1,428 per year. Of course these are ideal conditions which we never have.

    Sadly we have been impacted by the so called Carr fire for over a month. We were fortunate not to lose our home. The impact on two factors has altered our solar situation. Smoke from the fire has nearly obscured the sun for most of the days of August and some smoke cover still exists into September. Our solar production is off between 20 and 25% so we've had to buy some grid power to get through every day since the fire raced through our neighborhood on July 26-27. On the other hand normal daytime temperatures have been held down, also due to the smoke, which has somewhat cut our Air Conditioning for the house. Normal daytime temps for the month of august are more like 105-112 but have been in the low 90s.

    For the year we are ahead. We've produced more solar power than we've used so we are at more than break-even with the electric company for the year. I count charging the Clarity as zero cost even though the solar system was expensive. But the solar system was sized and installed for the house, not the house plus car. So being able to charge the car is a big bonus. Even so, without solar, we would have lowered our fuel cost by buying the Clarity. Overall, considering all costs, the Clarity has been a huge bargain.
    Akinto, Peter CC and Kendalf like this.
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  8. StickWare

    StickWare Active Member

    I changed my energy supplier for the reason. Down to 5.79 cents a kwHr
    Texas22Step likes this.
  9. jorgie393

    jorgie393 Well-Known Member

    [Shhh: a secret: Though the Clarity is saving me money vs my old Accord in mileage (which is the correct comparison), the Clarity itself is so efficient at 40+ mpg highway....and with gas prices and electricity prices the way they are here....when compared to itself, I actually pay the same or more per mile to drive electric on the highway vs. using the ICE.

    This was a bit of a surprise. Again, the fair comparison is vs the old car, but still.

    I still drive electric whenever I can for multiple economic and non-economic reasons, esp in city (where it’s a financial winner again), but the general point is that a lot depends on local economic factors.]
    Last edited: Sep 4, 2018
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  10. AaD

    AaD Member

    You may also find that you can get significantly better than 47 miles much of the season if you are in the Boston area. My wife commutes via Rt. 2 from metro west into Boston (round trip about 40 miles). We usually see estimated EV range in the low 60's for this commute of mixed country road, highway and city traffic. That will change in the winter, but we're pleased. And we're using solar, and net metering with eversource means we're actually payed more for the excess we generate in the summer than it will cost to make up any shortfall come March.
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  12. My son pays .01 per kilowatt hour on reduced rates after midnight in Atlanta area for his Leaf.
    That is a deal!
    jdonalds likes this.
  13. The college next to my house lets me charge for free. SoCal Edison offers .13 + .08 distribution for electric car fill ups after 9pm, but you have to have a separate meter added. No electrician in my area will take the job even though Edison offers a $1500 rebate. They don’t like the list of requirements Edison has. Even then .21 per kilo is pretty expensive, god help us when they eventually add road taxes like gasoline.
    MZ5, Peter CC and (deleted member) like this.
  14. RickSE

    RickSE Active Member

    Thanks for the quick replies. I used too poor or a worst case scenario for sure. Pulled into my work garage this morning and noticed that they had 10 charging stations. Since I pay for parking anyway they let me plug in for nothing. Guess I just stuck another $75 a month in my pocket!
  15. bpratt

    bpratt Active Member

    During the summer using the AC, I average about 4 miles per KWh according to the KWh meter I installed on the plug for my 240 V charger. Since I pay $.086 per KWh used, it costs me about 2.15 cents per mile to drive in EV mode. Gas in my area is about $3.15 per gallon so I'm getting the actual equivalent of 146.5 miles per gallon.
    Texas22Step likes this.
  16. stanigu

    stanigu Member

    We get screwed here in the San Francisco bay area. Cheapest rate from our local carrier is about $0.13/kwh after midnight. Goes as high as $0.45 during peak periods. Typical gallon of regular unleaded goes for about $3.70. (and a decent 3bd/2ba home is north of a million, but that's a different topic).
  17. Alantn

    Alantn Member

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  18. Heino

    Heino Active Member

    Dang. I guess I shouldn’t complain... GA power standard rate is roughly 6 cents for the first 650 KWh and 10 cents for the next additional 350 kWh. Generally my hosehold uses less than 800KWh per month.

    I think I am really going to like these savings. Drove to work for the first time today on all electric, after getting my Clarity last Friday.

    So much fun!
  19. V8Power

    V8Power Active Member

    Crazy awesome. Nearly free fuel!
  20. V8Power

    V8Power Active Member

    TOU low demand rate here near Toronto, Canada, is C$0.108/kWh from 7pm-7am. I started logging to understand efficiency. 403 EV km driven, no ICE at all, and charged 70.5 kWh measured at the JuiceBox Pro EVSE baking in losses. This amounts to C$0.019/km, about 11x less than with my old V8 gas guzzler at $0.22/km! I love EV mode :)
    Akinto likes this.
  21. insightman

    insightman Well-Known Member Subscriber

    So will you be changing your handle to I4Minimally?
  22. V8Power

    V8Power Active Member

    1. I don't see how to change it.
    2. It shows where I came from.
    3. I still love that V8 - it was a Japanese Lexus engine, so smoooooth and powerful.
    4. The irony!
    I think I'll keep it unless something more clever comes along and I able to change it.
    insightman likes this.

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