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"Official" recharge times

Discussion in 'Roadster: Technical' started by TEG, Nov 19, 2008.

  1. Doug_G

    Doug_G Lead Moderator

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    I think peak charging efficiency will require a bit more power. A good chunk of that juice goes into the cooling system instead of the battery; that's why 110V charging is so slow. It has been reported elsewhere on this forum that 240V 30A is the sweet spot. 40A is almost the same.
     
  2. vfx

    vfx Well-Known Member

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    Time permitting has to also apply to best electric rates too. If you charge continuously for 36 hours you will be paying a higher (sometimes much higher) rates for power in mid day. A faster night charge keeps the power bills down. 30 amps seems to work pretty well for hitting that window after coming home from work for a full charge in the morning. Nice to not strain the power company's output as well.
     
  3. dsm363

    dsm363 Roadster + Sig Model S

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    I'm pretty sure I pay a flat rate regardless of time here in Texas. I'll probably set it up at 30A then since 8 hours would be more than enough time to fill up the 40-60 miles I drive a day.
     
  4. vfx

    vfx Well-Known Member

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    Your price many vary.

    Who is your provider?
     
  5. tomsax

    tomsax Member

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    I agree with Scott, installing a NEMA 14-50 at 50A is the right thing to do. I don't think it will save you any money to install one of the lower-rated outlets on a smaller breaker and it will save you from having to buy another pig tail.

    You can still choose to charge at a lower rate by setting the current limit on the touchscreen. When you do that, the car remembers that setting for your home location and will keep using it until you change it. I charge at 32A which reduces the load on our panel, has about the same efficiency as charging at a higher rate, and might be a little bit nicer to the battery (Tesla says it doesn't matter).
     
  6. tomsax

    tomsax Member

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    You're not counting the losses due to charging overhead which are proportional to time spent charging. I studied this pretty carefully and reported the results on my blog:

    Tesla Roadster Charging Rates and Efficiency
     
  7. dsm363

    dsm363 Roadster + Sig Model S

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    #47 dsm363, Oct 16, 2010
    Last edited: Oct 16, 2010
    I have CPS Energy. Over 600 kWh it's $0.0843/kWh (up to 600 kWh it's $0.0668/kWh). I decided to pay for the wind energy program at 100% which adds $0.03030/kWh. I guess that brings it up to $0.1146/kWh. Maybe I should reduce my wind energy subsidy. It added $50 to my energy bill last month and I think the Roadster will balance out my green energy karma=)

    I sent CPS energy an e-mail asking them if they had a variable rate program like in California but haven't heard back yet.

    edit: Am I doing this math correctly? Assuming standard charge of 80% of a 54 kWh (0.8 * 54= 43.2) then my $0.1146/kWh * 43.2 kWh= $4.95 for a full (standard) charge? If I did that right, that's still pretty amazing to pay $5 to go 200 miles even with the wind subsidy. Of course that's negated by the new tires every 7500 miles=) Oh well, I'll have a blast doing it I'm sure. This wait is getting tougher and tougher. On day 10 but it feels like forever. I guess compared to the 18 months I was waiting for the Model S before I went with the Roadster, it's nothing. I don't know how you early adopters did it. Kudos to all of you.
     
  8. TEG

    TEG TMC Moderator

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    Your math seems about right, although it might use slightly more energy due to charging losses. Another way to look at it, is that the Roadster pack holds the energy equivalent of about 2 gallons of gasoline. Roughly $5 is ballpark the same as 2 gallons of gasoline right now. So it isn't that electricity is super inexpensive, but rather the Roadster is super efficient. Getting over 100MPGe in your high performance sports car!
     
  9. tomsax

    tomsax Member

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    Cathy and I pay for green energy which, in addition to the warm fuzzy feeling, means we have a great response to the frequent attack on EVs as just shifting emissions from the tail pipe to the power plant. There are great counters to that argument, but the easiest one is to say, "I use green energy to charge the car."

    We got 12,000 miles on our standard rear tires. Replacement cost was about $600 for the same tires through Tesla. You'll get less with more spirited driving, but I managed to have plenty of fun on those 12,000 miles.
     
  10. eledille

    eledille TMS 85 owner :)

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    The Norwegian EV association got so sick and tired of hearing the long tailpipe argument that they just bought sufficient renewable energy certificates to cover all EV charging in the country.
     
  11. dsm363

    dsm363 Roadster + Sig Model S

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    Good point. I guess saving $50 a month in energy shouldn't be a primary concern when you get a car like this. I'll keep doing the wind energy program. Hopefully enough people do it that they can reduce the premium they charge.
     
  12. vfx

    vfx Well-Known Member

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    How cool will it be to say "My car runs on Wind"?
     
  13. ChadS

    ChadS Last tank of gas: March 2009. EV miles: 254,000

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    When my wife asks me to slow down, I say "Sorry, the wind is blowing really hard today!"
     
  14. Kevin Sharpe

    Kevin Sharpe Active Member

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    I'm one of a number of Tesla owners in the UK that use 100% renewables from Good Energy;

    http://www.goodenergy.co.uk/

    We don't pay any premium for this...
     
  15. dsm363

    dsm363 Roadster + Sig Model S

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    That sounds great. I wish it was like that here but it's an extra 3.3 cents/kWh where I live. I guess they're not willing to have the broader customer base pay for the transition and put it more on the people who sign up.
     

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