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cost per charge at home ??

Discussion in 'North America' started by jmanning, Apr 24, 2017.

  1. jmanning

    jmanning Member

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    I go to car shows and other events and at times I get the question how much does it cost per charge at home, increase in electric bill, ect....
    We have solar panels, got them month before Model S. Because we get energy from the panels too, I can't calculate how much energy I am using nor the cost straight up.
    Anybody have figures on this using Massachusetts costs??
     
  2. Xenoilphobe

    Xenoilphobe Active Member

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    In Virginia we pay 10 cents a KW with NOVEC. 0 to full costs $9 (added some for charging losses)

    I have solar too, but leave that out for simplicity. So about 0.3 cents per mile. With solar I don't pay anything.
     
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  3. bakerboy

    bakerboy Member

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    I just got my 2013 MS P85 and was wondering this too, I currently have to charge my car with a standard 5-15 outlet, Im charging a rate of 4mi/hour, we have a 3 tier rate in my area:

    Tier 1: $0.16/kWh
    Tier 2: $0.25/kWh
    Tier 3: $0.31/kWh

    We usually fall into tier 2, I've been charging around 10-12 hours a night, do I just multiple the $0.25 x 12 hours = $3 to get my "daily" charge usage/cost?
     
  4. Haxster

    Haxster Member

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    After checking your W/mile energy use over the last 30 miles and your utility rate, this could get you close:

    W/mile x $/Wh x 1.2

    The 1.2 (my guess) represents losses in charging and vampire juice.

    So, if you run 300W/mile and pay $020/kWh, then it costs you about 300 x .2 x 1.2 ~= 7.2 cents per mile.
    Adding 100 miles costs about $7
     
  5. Reciprocity

    Reciprocity Active Member

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    I am getting around 9-10c per kWh so usually under $7 for 70kWh for an X75D. I have to charge between about 1-5am to get the best rates. I have actually seen negative rates where they pay me 1-3c per kWh to charge, but its like 5 days a year and typically is between 1-5am as well. I am in Chicago and have a smart meter and what Comed (electric company here) calls real time pricing which allows me to get cheaper rates during down times and higher rates at peak times. Also get a $10 a statement credit for the summer months to allow Comed to control my ac during peak times.

    Edit: So 200 miles for $7-$7.50
     
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  6. gfb107

    gfb107 Member

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    My electric rate is a flat rate at just under $0.12/kWh, My X 75D battery holds approximately 75kWh, so that's $9 for a full charge if there's 100% efficiency, but let's assume there's only 85% efficiency, so it's actually $10.60 for a full charge, but round it up to $11. EPA Rated range is 237 miles, so that comes to $0.0464 / mile.

    I tell people I pay under $0.05 for electricity per mile. Current gas prices here are $2.25/gallon, so my electric cost per mile is less than than the gasoline cost per mile for an ICE that gets an EPA rated 45 MPG.

    For comparison purposes (from The Most Fuel-Efficient SUVs ):

    Code:
    MAKE & MODEL                   OVERALL    CITY    HIGHWAY
    Toyota RAV4 Hybrid XLE         31         26      36
    Lexus RX450h                   29         24      33
    Lexus NX 300h                  29         23      34
    Honda HR-V LX                  29         20      39
    Mazda CX-3 Touring             28         20      36
    Mercedes-Benz GLA 250          26         19      35
    Subaru Crosstrek Premium       26         19      34
    Mini Countryman S              26         19      33
    Subaru Forester 2.5i Premium   26         18      35
    Hyundai Tucson Sport (1.6T)    26         18      35
    
     
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  7. oktane

    oktane Active Member

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    Close but no. The pricing you referenced above is per killowatt-hour, which is a unit of energy.

    In your case, since your signature suggests you have an 85kWh battery, your cost at Tier 3 is the following:

    0.31 * 85 = $26.35 per full charge.

    I am using Tier 3 pricing since unless you have solar, most likely you will incur Tier 3 pricing.
     
    • Informative x 1
  8. MikeBur

    MikeBur ManualPilot

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    @jmanning I let TeslaFi just figure this out as there's also vampire loss, etc. you can specify what the "cost" is based on whatever you wish. I use utility rate of $0.11 KW

    Couple of examples:
    IMG_0277.jpg

    IMG_0276.jpg
    This is adding 21 miles (from odometer) for $1.32 for $0.063 per mile.

    In terms of vampire drain, below is the best example I can find (ignore day between the 2, the car did charge in-between so is actually 4am day previous to 3:50am due to silly connectivity loss playing with VP s on my router)... anywho, it's ~$0.44 for just sitting there as vampire loss:
    IMG_0274.jpg

    So, I pay about 50c a day + 6c per mile.
     
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  9. SageBrush

    SageBrush Active Member

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    Answer #1: This gets 3.0 - 3.5 miles a kWh
    Answer #2: Get PV, then it is dirt cheap!
     
  10. Reciprocity

    Reciprocity Active Member

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    I don't think I could charge cheaper with solar then 9c per kWh and I am expecting a bit lower in the summer on real time pricing. It would be difficult to charge only during the day as my car is with me at work, though I guess I could charge half of what I need for the week on Sunday.

    I'm between a rock and a hard place on the solar. My rates are low and my home is very efficient and Comed has great rates with real time pricing. The payoff is like 13 years unless I use more energy for something that I don't have yet, like a hot tub it heated pool. Thought about switching to electric water heater but I'm pushing it with 200amp panel as it is.

    I need solar to come down a bit it hail to destroy my roof. I would seriously consider that slate wood Elon showed. A 50 year solar roof would as a fair amount of value to the home while also providing clean energy. Need to see pricing to see if it's worth it, but my roof is probably good for 10 years unless there is a big hail storm.
     
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  11. SageBrush

    SageBrush Active Member

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    These two statements are mutually contradictory

    Say you can generate 1.6 kWh a year from an installed watt
    To match 9 cents a kWh from your utility, the installed cost* would be $3.65 a watt after the fed tax credit,
    Or $5.21 before the tax credit

    *25 year life at nameplate capacity, calculated from 0.5% annual degradation and nominal 30 year life.
     
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  12. Brass Guy

    Brass Guy Member

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    Tell them it depends on how far they drive, about 7 cents per mile with electric rates as they are here in MA.
    Right now it is very close cost-wise to a 32mpg gasoline car, but you won't find a car with this performance and size that gets near that fuel economy.
     
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  13. Rocky_H

    Rocky_H Active Member

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    I actually just had this conversation with a friend recently, and I like to keep it simple and ballpark, so we can get to a realistic number quickly for that realization and "ah-ha" moment. Most people already have an idea of what they spend on gas and approximately what electric rates are, maybe, but I don't want to get much into electric car efficiency values. I say, you get about 3 miles per kwh, so take the amount of miles you drive in a year, and divide it by 3. For 15,000 miles, that's 5,000 kwh. Now what's the price per kwh for electricity? Here, it's about 8 cents. So multiply 5,000 by 8 cents, and that's about $400. Fuel cost. For the whole year.
    :eek:
    "Whoaaa!"
     
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  14. cgiGuy

    cgiGuy Active Member

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    Have you looked at the EV plans? Night time rates are ~$.11 I think, but start a little later than the normal TOU plan.
     
  15. Kanting

    Kanting Member

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    If you're with PG&E, log onto pge.com to change the rate plan. I have 2 EVs, so EV Rate Plan charging at night is definitely the best! The Off-peak is 11PM~7AM and is $0.11/kWh.
     
  16. SageBrush

    SageBrush Active Member

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    Better approach than my cents per mile -- that just not give them any perspective.
    Lately I've taken to saying "for our 16k miles a year, about $25 a month."
     
  17. jmanning

    jmanning Member

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    MikeBur, thanks for that info. Is that an app for TeslaFi, couldn't find it. We have solar too, so it might figure the electric use but having solar changes that a bit..
    Thanks to everyone for the info. Looking to cut one tree down and possibly add a few panels this year....maybe powerwall if producing enough energy and makes sense !!!
     
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  18. ecarfan

    ecarfan Well-Known Member

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    I think most Tesla owners get those questions regularly. I try to keep my first response very simple: "It costs me much less than half of what you pay for gas to go the same distance."

    That opens their mind and gets their attention. Anyone can understand that. Once that is established you offer more information on a basic level, as in "It costs me less than $9 to fully charge and it happens at night while I'm asleep, so I spend zero time doing it."

    If you first respond with an explanation of electrical costs per kWh, TOU and when to charge, how much stored electrical energy equals a gallon of gas, EV efficiency in kWh/mi, etc., most people get confused and you haven't made an EV convert. They think owning an EV is complicated, when in reality it is far simpler than owning an ICE in multiple ways.

    KISS.

    The most common question I get is "How far can you go?" By which they mean "How far can you go before you run out of juice?"

    Again, I keep it simple: "Just like with your car, that depends on how fast I go and if there is a lot of uphill or not."

    Then I give them my range number based going 65mph on a flat road and no headwind: "About 250 miles" (of course that was when my battery was new, by now it is somewhat less). Again, that opens their mind and gets their attention. If they want more details I can continue the conversation but the vast majority of people don't ask for details.

    KISS.
     
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  19. 2012MS85

    2012MS85 Member

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    KISS mantra is a very smart way to answer a complicated question since most people are very bad at math. I'm a numbers geek, so I quickly lose almost everyone when I start talking about kW power and kWh energy (most people don't care to understand the difference).

    I often mention Iowa's average 9 cents/kWh electric rates, divided by 3 kWh per mile, and tell them they could drive an EV for 3 cents per mile. Or they could install PV solar like I did and bring the incremental cost (of selling excess solar production back to the utility at 3 cents/kWh) down to a PENNY A MILE! Of that entire explanation, 90% of the population will only pick up the "penny per mile" cost of my EV driving.

    Then you have to explain that they are paying much more (even with $2/gallon gas in Iowa, and a great 40mpg car, the best case ICE driver is spending a nickel a mile). And if they're in an average SUV getting 20mpg, they're up to a dime per mile. And when gas goes back to $4, it'll double their cost of gas...while I'm still at a penny per mile ;o)
     
  20. SageBrush

    SageBrush Active Member

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    My explanation in the past to a tee, but I've decided to change my approach because the majority of Americans cannot make the mental jump from pennies a mile to thousands of dollars a year. So I translate for them into dollars a month.
     

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