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SolarCity is testing 8 kilowatt-hour battery (by Tesla)

Discussion in 'TSLA Investor Discussions' started by FreeOfPge, Jun 26, 2013.

  1. EarlyAdopter

    EarlyAdopter Active Member

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  2. SebastianR

    SebastianR Member

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  3. blakegallagher

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    Not sure but they have said when they are done testing ... 2015 they will be able to install in CA and in HA with each PV system and still sell electricity to homeowner for cheaper than Utilities ...



    Edit: Seems like there is a large market of "Preppers" out there that would love a solar system with a battery backup. Along with anyone who has every experienced a prolonged power outage
     
  4. Frankrb

    Frankrb Member

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    I have a 10.5 kw solar on the house and the other day with a power outage, realized that without a battery backup and bypass switch, I could not use the power i was generating...........just wasted! If you know anybody as Solar City that I could talk to about their system, I would be very appreciative.

    Frankrb
     
  5. Zzzz...

    Zzzz... Member

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    If grid fails, doesn't matter if you got solar on your roof or not. Even if solar system is capable to generate more then your house consume, it not going to supply you with power.

    Modifying solar PV system so it could serve as backup of grid connection is generally expansive and do not make economical sense. You would better be served by natural gas or diesel backup generators.
     
  6. electrictorque

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    I have a friend that is getting a Solar City Solar installation and he did asked them about the future battery backup, he was told that would cost him about an additional 1cent per KWH.
     
  7. AudubonB

    AudubonB Mild-mannered Moderator Lord Vetinari*

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    As I'm not on any grid (nearest lines are zillions of miles away), all my solar pours into a battery bank (see my other posts for more, and pix). Oh, yes, it's expensive...I've about $50K in the batteries alone...but then, I haven't any alternative.

    What I don't understand is the nomenclature. Each of my batteries is rated at 1100 AMP-hours, not kWh. The latter is a head-scratcher for me.

    By the way, an Absolyte IIP absorbed glass mat 1100 A-h battery weighs 550 lbs, without hardware. With the thick copper buss bars that tie all 16 of these batteries to each other, plus the250MCM welding cable running the juice to the inverters, plus the mounting beams and such, my bank weighs nine tons. I try not to move it around much.....

    With that as perspective, the batteries Solar City is discussing seem like amusing little toys to me. Possibly enough to keep a light or two on in your house in case of an extended power outage, but not enough to run your refrigerator or freezers, let alone heat or a/c..... I'd definitely like more information in that regard.
     
  8. bond

    bond Member

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  9. jkirkebo

    jkirkebo Model S P85+ VIN 14420 EU

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    It seems you have the 6V batteries? So 8 in series and two parallell string for a total of 48V and 2200Ah? 48*2200=105,6kWh. Since these are lead acid you probably can't use more than half that if you want long life from them. So about 53kWh usable, the same as a Roadster pack.

    You'd need about 8 of the Solar City batteries for a comparable bank.
     
  10. SebastianR

    SebastianR Member

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    Agree - but I'm not sure if your situation is the relevant comparator: Since batteries are so expensive and provided you have access to the grid, you may just want to optimize usage of your PV and pay as little for grid-drawn electricity as possible (depending on local legislation about feed-in tariffs etc. etc.). So I have seen 2kwh offers in Germany and their argument is that intelligent home appliances, the right size PV and a 2kwh battery can reduce your grid consumption by 80% by switching heavy appliances (dishwasher, dryer, washing machine, AC etc.) on an off depending on sunshine and using the 2kwh buffer for bad days, evenings and mainly lighting.

    No idea if it works exactly as advertised, but I think that with intelligent power management, you can save a whole lot of batteries...
     
  11. richkae

    richkae VIN587

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    The 8kWh batteries are not targeted at someone off grid who depends on their system to survive and needs to run their entire home - but instead someone who very occasionally has to deal with the inconvenience of power going out for a day or two.
    8kWh is not going to run A/C for any meaningful amount of time, but it is sufficient to allow a gas furnace to operate and keep you warm.
    An energy star fridge or freezer can easily consume less than 2kWh per day. The 8kWh is probably enough to keep just about everything you really need on overnight until your solar panels refill it.
    If the sky gets cloudy and you don't get any solar input, you can probably keep your food from spoiling for several days by turning everything else off.
    Recalling the last time my power was out for a long period of time ( 6 days, in the middle of winter ), the 8kWh probably would have lasted me about 2-3 days ( because solar doesn't do much in Seattle winter ) and then we would have started getting cold - so I have a generator.
     
  12. sleepyhead

    sleepyhead Active Member

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    The reason for the 8kWh battery doesn't have much to do with power outages. It has more to do with trying to solve Solarcity's biggest risk and that is net metering. If the governments take away net metering (and they certainly will eventually) then Solarcity's business model is shot and so is your 20 year solar lease that you signed.

    Since you are producing electricity from solar panels during the day when you are at work, and consuming in the evening/night when the panels aren't producing you have to have net metering in place in order for the financials to work out. By installing an 8kWh battery, you could charge the battery during the day and drain it during the evening/night and not have to rely on net metering.

    Net metering is a huge risk for Solarcity and it is great that they are trying to find ways to solve this. This is also one of the reasons why solar companies are only successful in states like California, New Jersey, Arizona, etc. Other states that don't have net metering policies in place are not profitable for Solarcity nor the customer.

    There are a lot of Solarcity investors on this board, but not many really understand their business model and/or risks. I would really recommend doing a lot more research in a company that you invest to maximize your profits. You can still make a lot of money by blindly investing in Solarcity, but you will never maximize your gains if you get out too soon or worse hold on too long. By understaning the risks, you should be able to realize when it is time to sell as these risks begin to materialize.
     
  13. blakegallagher

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    I am in this category for sure. TSLA is my only other investment and I spend more time then I should keeping up with it. I have taken a small portion of TSLA earnings and bought a few long term calls for SCTY and dont really watch them that close. I know I should find out more about the company but for now I just have a basic understanding of their business model and the threats to their success. Although when I first bought the options all I knew is it was trading in the 50's the month before I bought it and it was only 36 when I got my Options lol .... naive way to invest but it was a small investment.
     
  14. djplong

    djplong Member

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    According to my electric company, the worst month I ever had was an average of 50 KWh/day. My best averages were in the 27-29 KWh/day. Not hard to figure where the 8 KWh batteries would fit into that equation.
     
  15. Robert.Boston

    Robert.Boston Model S VIN P01536

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    Your usage is fairly for a typical US household; utilities usually model a household as using about 750 kWh / month, or about 25kWh / day. An 8kWh battery would cover an outage of up to 8 hours of typical use, which covers about 98% of outages (http://certs.lbl.gov/pdf/54365.pdf, Table 3-2). If you turn off non-essential loads, such as pool pumps, and take other conservation measures such as adjusting thermostats, most households would find an 8kWh battery fairly useful in an outage.

    Now if only we could just use the 85kWh battery parked in the garage...

    I strongly support @sleepyhead's conclusions about net metering, though: this gravy train for distributed generation will have to come to an end in places, like California, where the installation of lots of PV is badly misallocating the cost of maintaining the bulk power system. Going completely off-grid, ideally, or carefully managing the peak draw on the grid will be important to managing your future power bills.
     
  16. EarlyAdopter

    EarlyAdopter Active Member

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    Yes, my wish as well. Nissan is testing using the 24kWh battery in the Leaf for home backup power in Japan. Evidently the "Leaf to Home" power station to enable this is $6000.

    Tesla, if you're listening, I'd love something like that, too.
     
  17. rolosrevenge

    rolosrevenge Dr. EVS

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    Right behind you...
    But then people like me will come up with all sorts of crafty ways to make lots of money for me, you, and the grid...
     
  18. Palpatine

    Palpatine Banned

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    Tesla/Solar city should have a program to adopt a used 60/85 kwh battery pack at end of auto life. Maybe at 10 years old it will have 50% to 70% of original capacity. Just figure out how to place it in the garage to use as backup grid storage hooked in with the solar system.

    Forget this 8 kwh stuff. 40-50 kwh from a used Tesla battery pack would be more useful.
     
  19. maekuz

    maekuz Member

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    This is definitely a future market for used Tesla Model S battery packs. Although i expect to Tesla to integrate those used battery packs into superchargers first to enable off-the-grid charging.
     

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