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Power your home from the battery

Discussion in 'Battery Discussion' started by Selector, Jan 10, 2012.

  1. Selector

    Selector Member

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    Can the car battery supply electricity to your home? I think it can because the car itself has an DC / AC inverter, and maybe Tesla should put a button that says "Power the House" and you just connect the car to your house. :smile:
    The average household spends ~ 4 kWh daily, which of course is not a problem for a Tesla battery. This is possible right?
     
  2. widodh

    widodh Model S R231 EU

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    In theory it is possible. Nissan has presented this with their Leaf. Although I think you use more then 4kWh a day, but on the other hand, if you know you are running on the battery of your car, you'll probably be more conservative.

    I don't think that Tesla has any plans for this at the moment.
     
  3. Doug_G

    Doug_G Lead Moderator

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    Tesla has stated that this will not be supported by the Model S.
     
  4. Robert.Boston

    Robert.Boston Model S VIN P01536

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    I expect that Tesla doesn't like this option from a battery warranty perspective -- extra cycles, but no miles. Too bad, really; EVs could in theory provide valuable electric grid support services ("VtoG" or, as I prefer to call it, "carbitrage"), providing reserves and ancillary services by being able to sell power back onto the grid during peak hours.
     
  5. Lloyd

    Lloyd Active Member

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    I would expect that the little that you get from the power company for the power stored in your battery will not offset the cost of the wear on your battery, or the loss of your battery warrenty with Tesla. We as owners need to have an idea of what a full charge cycle will cost. If we can expect 3000 cylces (guess) from our battery, and a new pack costs $15000, thats $5 per cycle. if you sell 60 Kwh at .12 per kwh you would make $2.20. If you charged at .06 per kwh at night that would be $3.60 making a net loss of $1.40 Would it be worth it??? I just don't see the economics in this. Who pays for the equipment to enable this transfer safely?
     
  6. jaanton

    jaanton Roadster NA #1026

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    #6 jaanton, Jan 10, 2012
    Last edited: Jan 10, 2012
    Something like 18 months ago I read an article that someone/organization demonstrated a house being powered from a roadster. I can't find that now. I agree that the wear on the battery probably makes it not truly a good idea. But for emergencies maybe. Also, once roadster batteries start to be replaced, i.e. when they have dropped to maybe 70% of original capacity, it might make sense to extract the old battery and use it for home power storage. I'm eagerly waiting to hear what happens to roadster batteries when they are replaced. I think only the earliest models are even close to being ready for replacement.
     
  7. shark2k

    shark2k Member

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    I think the average is more like ~20 kWh give or take a few kWhs.

    -Shark2k
     
  8. dsm363

    dsm363 Roadster + Sig Model S

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  9. shark2k

    shark2k Member

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  10. Robert.Boston

    Robert.Boston Model S VIN P01536

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    That's because you're not doing the economics quite right. Under FERC Order No. 745, issued June 2, 2011, "demand side management" (which includes behind-the-meter generation, such as injections from batteries in your car) has to be paid at the "full Locational Marginal Price." Now, there's some fine print in there, and you have to be aggregated up so that you're a wholesale resource, not merely running your distribution meter backwards, but at least in principle you could get paid up to the wholesale price cap for the power. The cap varies by area; in New England, it's $2/kWh; in Texas, $10/kWh; in California, $1/kWh. Here in Boston, if my parking garage aggregated all of the EVs plugged into its free charging stations (they're up to 14 of those now) so that we could sell to the bulk power system, I could charge overnight at $0.06/kWh, sell in extreme conditions at, say, $1/kWh, and earn $50 or so.

    You can also get paid merely for being ready, willing, and able to inject power, even if you are never actually called upon. This is called "spinning reserve" or "synchronized reserves." The price is usually pretty low (~$3/MW/hour), but sometimes it, too, can go up to the wholesale price cap.
     
  11. Lloyd

    Lloyd Active Member

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    Interesting! Thanks for setting me straight!!
     
  12. Citizen-T

    Citizen-T Active Member

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    I like the "emergency" case. I'd love to be able to just turn this feature on when my power goes out.
     
  13. roblab

    roblab Active Member

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    If you already have PV, or are planning to get PV panels, the cost to go to an emergency off grid situation for a day or two is not nearly as expensive as buying an electric car: Lead acid batteries, large and heavy, are cheap by comparison to the light, small batteries required for automotive use. I have a couple thousand dollars in sealed glass mat lead acids that are supposed to last ~20 years with absolutely no maintenance other than the charging supplied by panels. In case of grid failure, the batteries kick in, in 1/300th of a second with computer grade sine wave. A gas fired generator would cost more than the battery system upgrade.

    My house uses about 17 kWhk, the water pump and septic pump use about another equal, and the electric car uses another similar (YMMV)
     
  14. dpeilow

    dpeilow Moderator

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  15. Doug_G

    Doug_G Lead Moderator

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    I would suspect air conditioners. Also houses in the southern USA have crappy insulation, which doesn't help with A/C.
     
  16. jcstp

    jcstp Active Member

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    #16 jcstp, Feb 16, 2012
    Last edited by a moderator: Mar 13, 2016


    one way to get off the grid and live of batteries
     
  17. vfx

    vfx Well-Known Member

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  18. ToddRLockwood

    ToddRLockwood Active Member

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    Not only "not supported," but will void the Model S warranty.
     

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