Equivalent $/kwh to $/gal for Clarity?

Discussion in 'Clarity' started by Kathy, Aug 1, 2018.

  1. Kathy

    Kathy New Member

    I bought my Clarity over the weekend, my first plug-in vehicle. I'm still learning all the nuances of EV charging. Some public pay chargers I notice charge as much as $.56/kWh for electricity. My own peak (4pm-9pm) electric rates (PG&E) are $.37/kWh with $.27/kWh off-peak (solar system installation comes next).

    Right now I cannot charge my car at work and my round trip commute is 60 miles, so I am having to burn some gasoline every day. I had set my Hondalink app to start charging at 9pm to avoid the peak rate, but then my battery is not fully charged by the time I leave in the morning (Level 2 charger also coming).

    Has anyone done the math to convert $/kWh to $/gallon given the actual performance of the Clarity? I am trying to decide if it makes economic sense to pay peak electric rates to fully charge my battery, or even public charger rates which are much higher, to avoid burning gas to save money.
     
  2. Odobo

    Odobo Active Member

    Assuming you can get 42 mpg on HV mode and 87 gas is $3.5/gallon, then your average $/mile is about $.083.

    Then assume the actual usable battery in EV mode is about 14 kWh, charging full range at $.56/kWh is $7.84, and assuming you get 47 miles out from it and it will cost you about $.167/mile

    If you use those number for calculation, you will need to get a charge rate $.27 to save fuel cost. PG&E has a EV A plan with off peak (11 to 7) at $.125/kWh I think... At least in my area
     
  3. PHEV Newbie

    PHEV Newbie Well-Known Member

    We pay about 10 cents per kWh. Gasoline is currently about $3.20/gallon. I'm getting about 60 miles per full charge (about 14 kWh according to posters who measured) so about $1.40 per 60 miles so about 2.3 cents per mile. I do mostly in town driving so my Subaru Outback gets about 23 miles per gallon under the same conditions or 13.9 cents per mile. So from a fuel cost basis, it's about 1/6 the cost to drive my Clarity compared to my Subaru. That difference is less in the winter when there's little change in the Subaru mileage but a big drop in EV range. I do the comparison with my other car instead of the HV mileage because the HV mileage is really excellent (so you won't see that great of a difference in cost if your electric rate is high compared to gas) and I like to know what my cost would be if I didn't buy the Clarity. We are thrilled. Much cheaper and a far better drive!
     
  4. Kathy

    Kathy New Member

    Yes I plan on switching to the EV rate. I was going to wait until I go solar but maybe I should do that right away.
     
  5. bpratt

    bpratt Active Member

    If I lived in an area where it cost me the same amount to drive on electricity as gas, I would still have purchased the Clarity. If electricity cost were a lot more, I would have purchased a hybrid. I'm lucky I live in an area where electricity cost is just under 9 cents per kWh or about 2 cents per mile.
     
  6. Chooch

    Chooch Member

    Electricity costs me $0.16/kWh (24/7, no EV or TOD discount rates where I am) and a full charge at home takes about 15 kWh. Therefore the cost is about $2.40 for me to fully charge. At this time of year I am getting ~60+ miles range per full charge so the cost per mile is about 4 cents. In the winter I think I got an average of about 40 miles per full charge so it would be about 6 cents per mile then. The current cost of gas around here is about $2.75/gallon so assuming I get the rated 42 miles per gallon, the cost on gas is about 6.5 cents per mile. So for me, EV is cheaper year round but considerably more so in the summer. With your electricity cost numbers, I think operating on gas is likely cheaper year round if your operating conditions and price of gas are similar to mine. I have never used a public L2 chargers bc they are always more expensive than operating on gas for me, unless they are the free ones.

    BTW- we have solar PV system but unfortunately bought it years ago so it isn't sized to also accommodate charging the new car. I'd recommend that you consider making your PV array large enough to cover the car charging if possible- to do so I think I would figure at around 16 kWh times 365 charges/year*6/7 (assuming you'd fully charge 6 days a week) so that would require 5000 kWh/yr right there which is probably at least 3.5 kW I'd think. Our entire array is a 7.7 KW system and generates I think about 10,000 kWhr/yr so adding an additional 3.5 kW is substantial in cost and roof size needed. I would also ask your solar company to quote installing a Level 2 charger at a discount for you when they install the PV since they will have an electrician wiring stuff at the panel then anyway.
     
  7. Odobo

    Odobo Active Member

    The thing about solar panel and charging EV is that unless you charge in day time or you install a battery as well, it doesn't really help charging the car at night. PG&E FAQ say the surplus compensation is average $.03/kWh, so even with that the peak rate is still going to be higher than gas, and the average saving with that is $.42/charge to full range
     
  8. LAF

    LAF Active Member

     
  9. LAF

    LAF Active Member

    surprised you can't bet back and forth all EV???
     
  10. weave

    weave Active Member Subscriber

    You also need to consider that electric miles won't wear the engine out as fast. Even if electric was somewhat more expensive than gasoline, I'd still run electric.
     
  11. su_A_ve

    su_A_ve Active Member

    I did it simpler - My electricity rates (with delivery chargers) total $0.15 per kWh so a full 15kWh should be about $2.25

    I get free charging at work and commute is 12 miles each way. Being extremely conservative, I figured I'd do a full charge once a week at home and fill the tank once a month - assuming $20 at $3 per gallon (currently about $2.80). Total of about $32. This beats my 3 times a month fill-ups totaling around $135.
     
    Johnhaydev likes this.
  12. AaD

    AaD Member

    Note that this varies wildly by state and your utility- in MA, we are effectively paid the straight base rate (about 0.22 per kwh including delivery) for all surplus pushed back to the grid, and pay only a $7 customer fee monthly. Net metering rules here are great for us, as we can charge whenever we want to - we should find out around March if we covered all our use. Unsurprisingly, the utility is adding fees for new net metering customers, but we are grandfathered in.
     
  13. Carro con enchufe

    Carro con enchufe Active Member

    Wow, I guess I lucked out. I charge mostly at free public chargers, so last month paid $12 home charging to drive 1200 EV miles + 60 HV miles
     
  14. Atul Thakkar

    Atul Thakkar Active Member

    For Canadians Clarity is miracle. We have gasoline cost @ C$1.37 per liter , so about C$ 5.18 per gallon. Our electricity rate off peak is C$ 0.065c per KWH, so my charging cost per full charge max is $ 1.25 as per charge point app. this give me 80 to 85km per full charge. on Gasoline my cost per km is 13.7c/km v/s charging is less than 2C/km , so now I just enjoy , do not count anything moving forward.
     
  15. Numbernine

    Numbernine Member

    I'll second this statement and back it up with my data so far!

    - Car was delivered to me with 12km on it, and current odometer is 513km. Thus, I've driven 501km so far.
    - Car has only been charged at home, and only when time-of-use rates are at their lowest. Current 'low' rate is $0.065/kWh.
    - ChargePoint Home charger reports 82.573 kWh have been used for charging so far.
    - (82.573 kWh) * ($0.065 / kWh) =~ $5.37 spent so far.
    - ($5.37 / 501km) * 100 =~ $1.08 per 100km.

    Now, previously, I was driving a Civic Hybrid...
    - Lifetime fuel economy has been about 5.7l/100km.
    - Cheapest gas price near me is currently $1.199/l.
    - (5.7l/100km) * ($1.199/l) =~ $6.79 per 100km.

    So, for regular commuting and errands around the city, the Clarity costs me about 1/6th as much to drive. Not too bad. :)
     
    JCEV and Akinto like this.
  16. Alantn

    Alantn Member

    I think we are a bit optimistic on the charge rate. You won't get 100% depending on charger efficiency so it would cost a little more to charge the full 14kW. Level 2 (220/240v) is better than Level 1 (110v) charger, also take that into consideration for your calculations.
     
  17. JCEV

    JCEV Active Member

    Triple that Canadian statement. Make sure you add the delivery costs making it closer to 8cents.

    Even with that AND a full charge at 15KW usage (assuming 1KW loss) I'm looking at $300 a year for 18000 km. Simply unbelievable. My SUV with the same mileage was close to 3200 a year in gas. Let that sink in... 2900 a year savings. Needless to say the Lexus will not be getting much use anymore . No wonder you can't find these cars here.
     
    Numbernine likes this.
  18. KentuckyKen

    KentuckyKen Well-Known Member

    Based on the sum total of many posts, it would seem that a full charge requires ~14.4kW. That is the amount you have to pay for coming out of the wall to the car’s inverter which as you mentioned is less than 100% efficient. If you’re measuring cost, you don’t have to take into account the efficiency or how much of that 14.4kW you paid for actually enters the battery. It’s some what analogous to the cost of a gal of gas not depending on how much tax is included in the price. The price you paid at the pump is what counts when you’re figuring out your cost per mile.

    The best assumption I’ve seen seems to indicate Level 2 charging is ~86% efficient. Assuming that level of efficiency, then ~12.4. kW is the usable amount of the battery capacity and ~2kw is lost to heat at every charge. But you still have to pay for the 14.4 kW to get the full charge.
    Assuming all this, then we are using about 73% of the 17 kW battery in the Clarity and the battery management software keeps from completely discharging or completely charging the full 17 kW which if done would destroy the Li-ion battery fairly quickly. And this is approximately in line with what’s being reported in other EVs like the Volt. What we don’t know is how much of that assumed ~27% is buffered at the top and at the bottom.

    I think it’s safe to say that Honda has designed the BMS to safeguard our battery to the extent that we can just charge it up without having to worry much about it. Especially since California owners get a 10 yr battery warranty so Honda must expect the battery to last at least that long.
     
    Numbernine likes this.
  19. Texas22Step

    Texas22Step Active Member

    As already noted by AaD in this thread, these numbers can be very different depending on one's location. The Canadians posting have already noted that EV driving of their Clarity, given their low electric rates and comparatively very high gasoline prices produces a Clarity "miracle" for them, as they are saving 5/6 (80%) to drive a Clarity on EV compared to local gasoline costs. Here in my area of TX, the electricity rates I have are also low ($0.078 / kWh (including delivery), 24/7/365 & fixed under a 3-year contract) but gasoline costs are currently also relatively low (currently about $2.50/gal, but recently as high as $2.90/gal), so the results of EV driving my Clarity yield a lower rate of savings here than in many other places but are still around 50% or so over gasoline driving. And this doesn't factor in the current TX state $2,500 rebate for purchase of a new Clarity, so if I figure that into the cost equation, I can drive the Clarity completely free on EV here for over 5 years (using only my home charging station at my cost). Yes!
     
  20. kent335

    kent335 Member

    @Odobo, that's not how Net Metering works with PG&E. You sell power from the solar panels at the retail rates to PG&E, and you buy power from PG&E at the retail rates. If you produce more electricity that you use from the grid, then PG&E will pay an average of $.03/kwh for the excess.

    For example, if I send 6,000 kwh in a year to the grid, and I draw 8,000 from the grid, PG&E pays the retail rate for all of the 6,000 kwh that I send to PG&E. The retail rate will vary based on the rate schedule that I am on, whether it is tiered usage, or Time of Day Usage.

    If I send 10,000 kwh in a year to the grid, and I draw 8,000 kwh from the grid, PG&E pays the retail rate for 8,000 kwh that I send, and will pay me an average of 3 cents per Kwh for the 2,000 excess kwh that I send to the grid.

    For solar and PG&E, it works best to be on a Time of Use plan. For example, I'm selling to PG&E power at 47.3 cents and at 26 cents per kwh during the peak and part-peak hours. I'm drawing power at 12.7 cents per kwh during the night to power the Clarity.
     
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