Tesla Abandons 10 kWh Powerwall, Only 6.4 kWh Daily Version Available Now

1 year ago by Mark Kane 80

Tesla Powerwall spec - March 2016

Tesla Powerwall spec – March 2016

Tesla Energy Powerwall

Tesla Energy Powerwall

Tesla Motors recently made some changes in its Powerwall offering.

In the originally released specifications there were two options – a 7 kWh ($3,000) and a 10 kWh ($3,500) home energy storage systems. The first was for daily use and the second intended only for back-up.

As it turns out, the 10 kWh version was abandoned due low demand and probably not that good value proposition (at just 500 cycles durability) compared to other solutions (even compared to lead acid batteries).

Greentech Media received comment from Tesla about the removing 10 kWh version:

“We have seen enormous interest in the Daily Powerwall worldwide. The Daily Powerwall supports daily use applications like solar self-consumption plus backup power applications, and can offer backup simply by modifying the way it is installed in a home. Due to the interest, we have decided to focus entirely on building and deploying the 7-kilowatt-hour Daily Powerwall at this time.”

Moreover, the lower capacity for daily cycle applications is now rated at 6.4 kWh compared to 7 kWh, at the same price of $3,000 ($469/kWh).

On the positive side is still the higher power output (3.3 kW) announced after the unveiling.  Tesla was heavily criticized at launch for just 2 kW of continuous output.

Multiple Tesla Powerwalls can be connected in parallel to get greater capacity.

Original Tesla Powerwall spec (7 kWh and 10 kWh) below:

Tesla Energy "Powerwall" old specs (click to enlarge)

Tesla Energy “Powerwall” old specs (click to enlarge)

source: Greentech Media via Autoblog

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80 responses to "Tesla Abandons 10 kWh Powerwall, Only 6.4 kWh Daily Version Available Now"

  1. Big Solar says:

    short? anyone anyone….

  2. tftf says:

    “the 10 kWh version was abandoned due low demand…”

    FUD, I tell you. FUD. Demand is off the charts. Elon said so.

    1. HeisenberghtNUTS says:

      Agree. To me it seems like demand was too high, and therefor Tesla chose to abandon 10kWh and reduce 7 to 6.4. This way they can deliver faster to more people. And in my opinion this is a smart move. Most people tend to buy more than they need. The higher delivery numbers will make stock holders happy, while shorter wait time will make consumers happy. From the grid viewpoint it also makes sense. At least in Germany lots of renewable kwh are lost due to overproduction. Local storage is the best way to solve the grid bottleneck.

      I don’t know what is the ratio of 10 vs 7 kWh orders, but just the reduction to 6.4 almost increases powerwall amount by almost 10%.

      1. tftf says:

        Improve your sarcasm detector 🙂

        1. HeisenberghtNUTS says:

          Oops you are right, a short look at your nick name should have told me that I am responding to someone not interested in pushing things forward to make the world more beautiful 😉

          Nonetheless I think that a higher delivery and installation speed will be good for the people and for Tesla, as this time Daimler followed quite fast with some real product. The faster Tesla can deliver the more market share they have secured, as those people who already have one power wall are unlikely to move to another es supplier for expansion.

          I wouldn’t be surprised if they also will soon offer even lower configurations at lower price.

          While I doubt that it will happen, a microwave oven sized device which you can just plug into one existing outlet would be a cool thing. A cheap sunlight detector outside could provide rough estimation on if storage or usage makes sense. Bluetooth or Wi-Fi are also cheap.

          In the holy Netherlands, micro inverters are legal.
          Why not think about micro peak shifting devices?

          This said, dear tftf I wish you some positive thinking!

      2. Bill Howland says:

        I bet they didn’t change a thing to ‘lower the 7.0 kw to 6.4 kw’.

        Sounds like the natural occurence of draining the unit at 3.3 kw, rather than 2.0 kw.

        Batteries are like that: the faster you discharge them, the more they heat, and the less usable power remains.

  3. RexxSee says:

    “The 10kWh model — designed for battery backup use during a power outage — has vanished from the product lineup. Given the unpredictable, infrequent nature of power outages, it stands to reason that the realistic use cases and resulting payback for a battery backup Powerwall are not attractive.”
    – Cleantechnica

  4. ModernMarvelFan says:

    The so called $3500 10KWh backup system never made financial sense.

    A comparable $3500 can get you a solid backup CNG/NG power stations that can supply you power for days… Sure it is dirty but it is far more reliable and powerful.

    The current financial investment with Power Wall only makes sense where peak/off peak rates are significant. That would require daily cycling to have any financial gain. At those price, it better works every day for a long time…

    I am willing to bet that 6.4kWh version is just a 10kWh version derated (almost exactly the same as the amount of derating used in the Chevy Volt battery from Gen I).

    1. Three Electrics says:

      The daily use system doesn’t make much sense either, at least for much of the U.S. SolarCity won’t sell it, for example: http://www.businessinsider.com/solarcity-says-no-thanks-to-teslas-new-battery-2015-5

      The reason is simple: at $3000 to store $1 of electricity, it’s far better to sell your solar energy back to the utilities using net metering. Otherwise, your electricity cost roughly doubles.

      However, for markets like Australia and Hawaii, where net metering has already reached its limits, the smaller Powerwall makes a lot of sense. And eventually net metering will be phased out across the entire world (populations can only use so much power at noon), in which case demand will spike. By that point you’ll probably have a large number of energy storage technologies to choose from, like flow batteries, CAES, hydrogen, etc.

      1. ModernMarvelFan says:

        Agreed that payback is too slow within the 10 year battery warranty period.

        That is the biggest risk.

  5. Speculawyer says:

    Yeah, that thing made no sense at all. Don’t buy an expensive Li-Ion battery to just have it sit there for months on end not being used at all.

  6. Scramjett says:

    That’s too bad. I was looking forward to getting this for an off-grid house. I don’t like the idea of lead acid batteries and Li-Ion is a much more attractive battery technology.

    I can see how it would not work in power outages. I’ve lived in SMUD territory for 9 years and I can count the number of times we’ve had a blackout on one hand.

    1. ModernMarvelFan says:

      10kWh won’t work for off grid house as it is not designed for daily usage or frequent usage.

      1. Scramjett says:

        By itself, no, but I recall Elon saying that these things were designed so that they can be installed in series. I figured 3 or 4 in series would work beautifully.

        As for daily or frequent usage, that depends on the cycle rating. Perhaps I’m wrong, but I would expect these to be designed with the same level of durability as the batteries in their cars which have a significantly higher cycling demand than something like a house would, even an off-grid house.

        1. ModernMarvelFan says:

          Yes, you are right that they can be configured in series or parallel.

          The problem is that 10kWh version wasn’t rated for daily cycling. You need that 7kWh version for daily cycling or frequent usage.

          I am willing to be the difference is derating. I wouldn’t count on the 10kWh version being your off grid power supplies.

          1. Scramjett says:

            The problem with the smaller 6.4 kWh (previously 7 kWh) systems is that they are limited to a 3.3 kW output. Most of the time that will work, but not when you try and run a clothes dryer. In theory, running them 3 in series should allow a 9.9 kW output, but something tells me the BMU won’t allow that.

            I’m with kdawg. Someone (Tesla?) should put together an off-grid package that can be scalable depending on size and projected usage. Might be a small market, but there would be a market.

            1. ModernMarvelFan says:

              I assume you want them in parallel so the “standard inverters” can be used…

              Either way, 3 of them would cost $9K which is a lot and only enough for 19.2kWh. That isn’t nearly enough for off grid system.

              You need at least 3x to 4x of that to be completely off grid…

            2. Pushmi-Pullyu says:

              Scramjett said:

              “In theory, running them 3 in series should allow a 9.9 kW output, but something tells me the BMU won’t allow that.”

              Assuming the home’s (or building’s) inverter can handle the current, I can’t imagine any reason that won’t work. Tesla shows photos of two PowerWalls connected together, and surely they will allow for more than 3.3 kW of power. Some electric clothes dryers pull 3.5 kWh, so 3.3 kWh isn’t going to cut it for the average American home owner.

              1. HeisenberghtNUTS says:

                It is possible to set up enough inverters to go off grid. Wk570 demonstrated that at Tesla motors club. However from a financial standpoint it might make more sense to replace certain consumers with alternatives which have lower peak current. I think you mention something similar further down, just overflowing the thread.

                The bad thing is, that often when you buy something it is not that easy to get information on peak current draw. It’s nice that people start to educate themselves about those issues.

                Maybe someone could set up a database for household devices and their current draw pattern. That would be a nice help for those off grid people. I agree that going off grid is most likely more a political statement than a money thing.

                It is nice to be free. Going off grid should be used until the power of the power companies is broken. After that point it will make sense to return to the grid for efficiency reasons. We are still far from that point, so I encourage everyone who has the money and time to go off grid. It can even be seen as a hobby. (a hobby rarely makes financial sense…)

                It would be quite easy to build a cloth drier with lower peak current draw (just manage heating and motor patterns differently) but there is no incentive for the companies to develop such devices until we demand them.

                They will save 5 bucks for a motor controller and thereby increase peak current draw by a factor of 10. No joke.

                We are the ones who decide. Will we keep buying household equipment which benefits the needs of electricity utilities (keep us in need to be connected… ) or will we work together to be free?

                In this sense : education is the key to be free.

                Most people know nothing about peak current draw.

                While a look at the fuse rating gives a rough limit, there is still no easy way to get real data.

                Demand management within the household is another way to reduce the need for oversized inverters.

                Yet another way is to have a separate 12V grid for led lighting and mobile phone and tablet and notebook chargers. Thus eliminating the stupidity to use an inverter and afterwards a transformer and AC-DC converter.

                When it comes to going off grid efficiency and load management is king!

                And while I really hate to say it, in some scenarios it might make sense to have an additional conventional generator.

                It all depends on the possibilities.

                How much solar capacity can I set up?

                How much wind capacity can I set up? (micro turbines are quite cheap nowadays…)

                How much can I reduce total power consumption?

                How much can I reduce peak current draw?

                Maybe someone with spare time can set up a web page consolidating the already available information. One could enter relevant information (location, roof size, household equipment, budget) and the page would calculate different scenarios. There is data on sunshine. There is data on wind. There is some base data on consumption. There is no connection of all this.

                1. Bill Howland says:

                  Oh, c’mon.

                  The usage by the motor is nothing compared to the heating element in an electric dryer. But the motor heat just adds to the drying effect.

                  I can’t believe anyone who is ‘off grid’ would run an electric dryer, unless he is rich.

                  Its rather like using solar power to run an electric resistance water heater. It would be far better to just heat the water using a solar loop (SUNWARD, etc) then waste valuable solar power for plain heating applications.

                  1. Scramjett says:

                    I realize I am replying 5 days later and that this probably won’t be seen, however, heat pump dryers like those used in Europe have a peak power output of between 2 kW and 2.5 kW. Also, heat pump HVAC have a peak power output of about 2 kW and use variable speed compressors (the one on my house has a minimum power output of 500 W). That technology was what I would be including in an off-grid house.

                    As for energy storage, I don’t think it is possible (yet) to have enough storage to cover inclement weather unless you live somewhere that rarely has it (i.e. the desert). You will need some form of backup generation akin to what I mentioned below. In this case, I think that having enough storage for overnight use plus a %30-%50 “reserve” would be plenty, and 3 or 4 of these powerwalls ought to be enough.

                    BTW, my 3 powerwall in series example was just that, an example.

              2. Liz says:

                If you live off the grid, I assume you use a clothes line, not a dryer…

                1. HeisenberghtNUTS says:

                  Personally I live off grid only part time 😉

                  But really, going off grid does not necessarily include leaving comfort behind… It all depends on proper planning. Choose the right devices, build some to your needs and enjoy freedom. I threw out all PC, as they have terrible efficiency. My monitor is one of the few that directly run on 12V. In fact I try to get rid of most 220V devices. And the cloth drier is one of my next projects. With 3 kids it’s really worth gold, but I am in the process of creating a 12V driven one.

                  1. ModernMarvelFan says:

                    Low voltage will require high current for the same power output which means thicker wires that are more expensive and hotter wires…

                    1. Scramjett says:

                      I think he’s talking about DC vs AC. My electrical engineering courses are years behind me, but, as I recall, you don’t need higher current switching from AC to DC even though your DC voltage is lower. That’s what has always made DC more attractive for efficiency. The problem with DC has always been that it can’t be efficiently transmitted over long distances. That’s not a problem in off-grid applications.

                      Having DC circuits is being looked at seriously here in California with the increase in renewables and the Zero Net Energy mandate. However, I think it is primarily being looked at for lighting and consumer electronics, not appliances.

                2. Joy Sabl says:

                  I’m on grid, got rid of the dryer years ago. Line dying is a free way to access both solar and wind energy, hanging the clothes is gentle stretching and exercise, a little wind takes wrinkles out if most fabrics, UV is a natural disinfectant, and sun-dried clothing and sheets smell fantastic. Confuses the heck out of me that it’s not the very first “eco” modification people make, unless they live in a truly tiny urban space, or someplace with super-bad smells.

                  1. ModernMarvelFan says:

                    I guess you don’t have kids and live in a wet area like Seattle…

                    1. Scramjett says:

                      Most likely. I can line dry clothes in Summer here, but our winters are wet and humid making even indoor line drying challenging. And, of course, there are the kids!

            3. Battery Bro says:

              They are scalable, and Tesla already makes commercial (larger) systems that could handle your needs. You just can’t but that from them at the moment.

              The nice thing about cells, which I’m sure you know is that they can be grouped and form larger batteries that work as a single unit. Eg. The sum is greater than the whole of its parts

              You can technically, scale the battery to be as large as you want. There is no limit except for space.

              Protective circuitry to manage a high number of cells is mature, and safety assured by separating battery modules and other things like what Tesla does in their cars (that have 7,000 cells I believe).

              So yeah, power-walls are available. And they can be scaled as large as you want.

              For DIY people, you can set yourself up a crude powerwall in just a day.

        2. Josh says:

          You can still string together the daily use batteries. If you need 20 kWh per day, just get three of the 6.4 kWh daily cyclers. $10,500 and you are all set.

          As someone stated above, the cycle limit is most likely due to the derating, still probably a 10 kWh battery pack in there.

          1. Josh says:

            Correction, $9k (plus install, plus some power source, presumably solar).

            1. kdawg says:

              Someone needs to put a package together for an off-grid house.

              Powerwalls(s)
              Inverter(s)
              Solar Cells
              Install
              ——–
              Total = ?

              1. ModernMarvelFan says:

                We would have to make some assumption on size of the system.

                Typical American homes need 1,000kWh per month.

                Assume $3 per W in total solar installation cost and you get 1500 hours per year per W of solar, you would get 1.5kWh of solar energy per year for each W installed.

                Assume your winter production is about 65% of your peak summer production and a back up factor of 30%.

                Then you would need 300kWh power wall at a cost of $3K x (300/6.4) = $141K

                If you assume 100kWh or 10% backup rate, then you would need $3K x (100/6.4) = $47K

                Yearly need is about 12,000kWh.

                12000/1500 = 8kW

                So, your solar system needs to be about 8kW minimum for a cost about $24K.

                Plus the inverter for the battery for another $2K and misc labor and fee for another $3K.

                You are talking about $76K to $170K where most of the difference are in the battery cost…

                That backup need depends on your weather pattern and how many cloudy or low generation days that you get in a row…

                10% is only 3 days consecutive and assuming full peak generation.

                30% is assuming 10 days without further generation degradation in the winter.

                1. ModernMarvelFan says:

                  Now if we use $0.20/kWh for 12,000kWh/year,
                  then that is annual cost of $2400.

                  $76K would mean a pay back of 31 years.

                  Will your battery last that long?

                  But as you can see that solar makes sense as it is a much smaller part of that upfront cost and will save you money quicker right of way…

                  1. ffbj says:

                    Suspect numbers. Average payback is around 10 years.

                    1. ModernMarvelFan says:

                      For solar panels alone.

                      Not to include battery cost and solar cost for a complete off grid cost vs. an on grid cost.

                      Which part of my estimate is “suspect”? Please point them out, I am all ears and willing to discuss.

                    2. kdawg says:

                      @ModernMarvelFan
                      But are you assuming electricity rates will stay the same over 31 years?

                      Also, couldn’t you reduce the amount of backup you need if you just install a fossil fuel backup system?

                2. Scramjett says:

                  This would depend on where you plan on going off-grid. If you’re buying property with no utility connection at the lot line (which is what I’d likely be doing), then going off-grid makes a heck-of-a lot more sense given the cost of paying utility companies to extend utilities to the house (I’ve heard upwards around $50,000 to $100,000 per mile). You can probably reduce some of that cost by including (dare I say?) a propane fueled ICE backup generator (or dare I say this?) a propane fuel cell backup generator that can provide 5 to 10 kW of peak power.

                  1. ModernMarvelFan says:

                    Yes, in those situation a propane based generator would have been cheaper than connection fee or large battery system.

                    But the use case for that market is relatively small for majority of the population.

                    1. kdawg says:

                      I see Scramjett mentioned other backups.
                      I’m also thinking (me personally) would need less than the average home. Was thinking more for a tiny-house, off in the wilderness.

                    2. Scramjett says:

                      That’s a good point kdawg. A tiny home probably wouldn’t need as much storage and could go without a propane backup generator. A tiny home wouldn’t work in my scenario given my wife’s rather large family though (they visit quite often). But we’re not looking at a “McMansion” either because…well…who the heck wants to clean all of that?

                3. Pushmi-Pullyu says:

                  ModernMarvelFan said:

                  “That backup need depends on your weather pattern and how many cloudy or low generation days that you get in a row…

                  “10% is only 3 days consecutive and assuming full peak generation.

                  “30% is assuming 10 days without further generation degradation in the winter.”

                  It makes no sense to pay for more battery capacity for those cloudy winter days, at $1000/kWh, instead of more solar panel area, at $3/watt.

                  Instead of having 3 or 10 days of backup power, have only enough to get through most of one day, and use the off-gridder’s rule of thumb that you’ll need 4x as much surface area in solar panels on a cloudy day as you need on a sunny one. Buy a lot more solar panels, so you don’t have to buy any more battery storage capacity.

                  Plus, if you’re contemplating a serious investment to go mostly (not entirely) off-grid, then consider alternatives such as a gas-powered clothes dryer, and either a ground loop heat pump air conditioner or else a gas-fired air conditioner. If you live in an area where you need to run a central air conditioner for months out of the year, then either will cut your energy cost substantially.

                  Trying to go entirely off-grid is a foolish waste of money. It’s well worth the monthly fee to be able to depend on grid power during an emergency loss of solar power, such as if your solar panels get covered with snow, or for those few cloudy winter days when you need just a bit more power. You’ll pay far less to stay connected to the grid, in most areas, than trying to cover the last few percent of your annual needs just so you can go entirely off-grid.

                  1. ModernMarvelFan says:

                    I agree with mostly what you said…

                    The best off grid plan is to shrink your total energy usage.

                    Tiny houses with less usage is by far the best way.

                    BTW, even 4x of nothing is close to nothing… =)

                    You will be surprised how little my 3.3kW solar panel generated on a rainy day… 1kWh in Northern California… So, 4x of that is still only 4kWh. 10x of that might work… but that is 33kW of solar which cost a lot of money and assume you got the surface for it.

                    1. Scramjett says:

                      Haha, yes. I also live in NorCal and I’ve had rainy days where my 2 kW produces a whopping 0.5 kWh with peak generation never exceeding 50 watts. Four times that would 200 watts, which, as you said, is 4 times nothing.

                  2. Scramjett says:

                    There is technology available (or coming down the pipeline) that could prevent using too much gas/propane. I was looking at an absorption heat pump for HVAC and water heating. You would be able to use solar water heating for the absorber in the heat pump and have gas backup (if necessary) to heat the water for the absorber (mind you, I don’t literally mean water, you’d probably run a lithium bromide solution through the solar/burner and the absorber).

  7. pjwood1 says:

    The 7kwh units are still popular, and according to the last earnings call, they are a net “cash positive” contribution. Arbitraging day and night production and use, with the higher life-cycle units still makes sense.

    Still 6.4kwh, on say a $.20 per kwh spread, or $1.28 saved per day, isn’t going to fund a whole lot. @$3,000 spent, before any interest rate, pays back in 6.4 years. This is why HI is about the only state in the US buying them.

    1. ModernMarvelFan says:

      $1.28 per day will take a long time to pay back…

      $3K is just battery packs. You haven’t included the inverter and installation cost yet.

      They are easily another $2K to $3K.

      The system pay pack is just a bit too long for it to make sense without financial incentives.

      1. ModernMarvelFan says:

        Also, the warranty is only 10 years.

        That means that you better pay back your initial investment within that time frame.

        This will add additional financial risks.

  8. Bevo says:

    In my opinion, Tesla has always been spot-on in regards to offering what folks would want- except for the 10 kWh rarely used back-up battery. From day one I couldn’t understand why they would push a product that isn’t meant for daily use, when everyone seeking to break free from the grid and utility monopolies has to use their battery back-up daily. As a solar customer (in Nevada no less), I’ve been waiting along with 17,000 other NV solar customers for a viable solution to break from the grid. I’m not sure why Tesla isn’t doubling down on residential batteries? With utility monopolies beginning to really run amuck I would’ve thought they’d be offering urban off-grid solutions in the near future, I would think they’d make a KILLING. Many non-EV folks would be buying residential batteries, hopefully we will see something larger (like the Power Pack for residential) that can power a home for a few days during cloudy periods.

    1. ModernMarvelFan says:

      ” hopefully we will see something larger (like the Power Pack for residential) that can power a home for a few days during cloudy periods”

      It is doable today by string together few of those Power Walls.

      The problem is cost. If we assume the worst case of having a period of 10 days of power need. That would imply a typical 300kWh for a typical American homes without EVs.

      That is a lot of battery. Even at only $100/kWh, you are talking about $30,000 upfront in battery alone.

      And you are also assuming that you got enough solar panels to over generate on good days to compensate for that 300kWh (worst case). That is additional increased cost in solar panels.

      Even with grid tied solar today, you are talking about decades of time before you can recover that cost vs. grid fee. Not to mention that eventually in 10-15 years, the battery will need to be replaced.

      1. Djoni says:

        This is why, they should work on a V2G within their own car.
        I know, it’s questionable that it would alter the life span of the battery, but if you limit the energy to tenth or so kWh, I don’t think it would be noticeable.

        1. ModernMarvelFan says:

          Still not enough for your house to be off-grid.

          But it will be nice to be used for a temporary power backup in emergency.

      2. kdawg says:

        Depends at how you look at “payback” too. How much does an inground swimming pool cost? What is the payback period (sorry that’s a joke). Inground pools can actually decrease the value of a home, but people enjoy them. And some people would enjoy just being off grid. Yes.. nerdy, but there are a lot of us nerdy people that look past the dollars and cents 🙂

        1. ModernMarvelFan says:

          “es.. nerdy, but there are a lot of us nerdy people that look past the dollars and cents :)”

          If you got $100K spare to be nerdy with… =)

          That is a lot of power you can purchase over the years..

          1. kdawg says:

            $100K, I’m not nerdy/rich enough for that (though others are). However I’d spend $30K to be off-grid before putting in a swimming pool.

            1. ModernMarvelFan says:

              LOL.

              I will pay people $5K to take away the pool for sure… =)

              Then again, I know few Model S owners who wouldn’t even blink with $100K toys… =)

      3. Nom de Plume says:

        You seem to be making the assumption that solar panels produce absolutely no power for long periods of time in winter. I have a friend who shared with me her solar stats for this past December, which was one of the gloomiest, foggiest, rainiest and snowiest months we’ve had around here in a long time. Her 10kWh system produced 250 kWh for the month, or an average of 8.3kWh per day. That’s with basically NO sun for the entire month. She was getting 3 or 4 kWh on even dismal days.

        You also make the assumption that all homes are energy hogs that consume over 30kWh per day. This is far from the case. Take the 4kWh from the panels on the worst day, add 20kWh of Powerwalls for nighttime use, and it’s quite possible for a well-designed, energy efficient home to get by.

        1. ModernMarvelFan says:

          “You seem to be making the assumption that solar panels produce absolutely no power for long periods of time in winter.”

          or very little power that wasn’t sufficient for a completely off grid system described here.

          ” I have a friend who shared with me her solar stats for this past December, which was one of the gloomiest, foggiest, rainiest and snowiest months we’ve had around here in a long time. Her 10kWh system produced 250 kWh for the month, or an average of 8.3kWh per day. That’s with basically NO sun for the entire month. She was getting 3 or 4 kWh on even dismal days.”

          Yes, a 10kW system. Do you know much power that same system would produce on a sunny day during the summer? Almost up to 60kWh!!!!! Compared with 3 or 4kWh.

          I have solar on my roof, so I am pretty clear on how much it does on good days vs. bad days… So, they aren’t assumption at all.

          Let us say it only produces 3-4 kWh per day. If my usage is 20kWh per day, then I would have to draw 16kWh from the battery. If those days continue for couples days, where do my battery charge from?

          Winter production on a sunny day is about the half to 60% production of a peak summery day. So, how do you return enough power to the pack if you don’t over install a much larger system.

          10kW solar system would cost about $30K upfront for a $3/W installation cost.

          “You also make the assumption that all homes are energy hogs that consume over 30kWh per day. This is far from the case. Take the 4kWh from the panels on the worst day, add 20kWh of Powerwalls for nighttime use, and it’s quite possible for a well-designed, energy efficient home to get by.”

          To get by. for how long? How many days can you sustain that? 20kWh of powerwall already cost you more than $9K in cells alone. That is only good for about 1-2 days. What do you do on the 3rd day and 4th day if your solar is only on 50% generation which is sufficient for your household use but no spare to recharge the battery? What do you do on the 5th day?

          Remember this is completely off the grid model where the entire house is depending on it.

          Sure, cutting back the house size and energy need will help. But that naturally reduces the cost in the first place.

  9. Bill Howland says:

    The only time I really see these things making sense is for an ‘off-grid’ application where reliable power is needed, in moderate locales where there is no Snow Cover. They won’t work in locales such as mine since I go 1-3 months (1 month this year on a warm winter, and 3 months last year on a record cold winter) without any Solar Production.

    “Grid-Tied” alternative-generation is not allowed with Net-Metering (a bigger bonanza than battery power) in NY State.

    A remote cabin in the woods, or a mechanized railroad crossing, that happened to be far from any power lines where the construction cost would exceed $10,000 would be served by Solar Panels or small wind turbines and then Tesla Power wall batteries and the requisite dc-ac inverter to provide 24/7/365 service.

    But utility rates would have to skyrocket in places where they are already ridiculously high in order to arbitrage time-of-day rates, with supposed savings from the batteries. Supposed since the payback time is about the life of the batteries, and you’d be crossing your fingers that there would be zero unexpected expenses in the interim payback period.

    For most situations, its too much stuff to make it worth the homeowner’s effort.

    If the battery could be trusted to last 30 years, then that would make the units somewhat desirable.

    1. Bill Howland says:

      That is to say, Net-metering WITH batteries is not allowed in NY State. Obviously what was mentioned IS allowed if there are no batteries.

  10. Ian says:

    If you have the money and you want it…just buy it. When it comes to buying products like EVs or solar panels or Tesla power wall people feel like they have to justify the money they spent. Screw it…just go buy it and tell your friends that you just wanted it so you bought it and be happy with your new toy.

  11. David says:

    Modernmarvelfan,

    That is beyond worst case, and, I think overkill. I’d certainly know better than to do a lot of vacuuming, hair drying, or clothes drying during a power outage.

    1. ModernMarvelFan says:

      That isn’t power outage we are talking about here.

      I am talking about the proposed off grid power for NV owners completely. 300kWh is about what typical homes uses in 1/3 of the month.

      Are you going to stop living when your solar panels don’t generate much in the winter?

      What are you going to do? Hibernate? =)
      That would be efficient.

  12. Bill Howland says:

    Reading between the lines here, I’m assuming Tesla discontinued the backup battery model since they are not price competitive with either medium life(15 year), or long life (25 year) lead – acid batteries, where, in stationary applications, the smaller size and weight of Lithium Ion batteries are not so much of an advantage.

    I know of one downtown theater that takes care of its emergency power needs with lead acid batteries and a 30 kw inverter, since roof mounting of an emergency generator would have been far more expensive, which is somewhat debatable, but these things do have their place, and the price premium may be softened by the simple convenience of using this small, wall mounted equipment.

    SO I’m rather surprised that Tesla is discontinuing it. I suppose other manufacturers will supply/service the market for any early adopters who previously

    1. ModernMarvelFan says:

      “downtown theater that takes care of its emergency power needs with lead acid batteries and a 30 kw inverter, since roof mounting of an emergency generator would have been far more expensive”

      Why would a 30kW generator be more expensive?

      A powerwall with 30kW output would require 15 of those 10kWh version which would cost about $45K in battery alone. (Each 10kWh is rated only for about 2kW output). YOu would still need that 30kW inverter which would easily cost another $5K to install. That is easily $50K right there.

      Typical 30kW generator would cost about $9k to $15K. I can’t imagine it would cost more than $45K to install it…

      1. Bill Howland says:

        It frankly could have been done either way, but not as cheaply as you’d think since there was no real estate for it on the ground.

        The emergency generator could have been put in the basement, but then A remote radiator fan, and room ventilation would have had to be provided, as well as hundreds of feet of supply and return radiator piping, electric fan, and additional water circulator pump – it could have been just the architech’s preference since lead-acid batteries require less monthly maintenance than do emergency generators.

        Also, battery maintainers use less electricity than jacket heaters for generators (assuming they decided to ‘save money’ and put the whole thing on the roof.

  13. PVH says:

    See below link regarding comparison of such li-ion battery storage systems made in Australia:

    http://cleantechnica.com/2016/03/22/household-battery-storage-a-comparison-of-product-price-performance/

    It seems to appear that the Tesla Powerwall is not competitive as compared to other similar products (see one made by LG Chem in that comparison). You just can’t hype your way in a commodity market as easily as Tesla thought they could. I hope they do not plan to keep the gigafactory busy with that business. (I hope Getreal reads this, I would be disappointed if he didn’t :-)).

  14. Alan says:

    What about V2H systems ?

    I am planning an 8kw solar system with at least one battery to top up whilst not at home but with a V2H system on top when they become available here in UK.

    If you have a 60kWh battery vehicle, it could make sense ?

    1. ModernMarvelFan says:

      60kWh car battery is decent for homes.

      Enough for 2-3 days..

      However, you also lose mobility if that happens unless you have nearby DCFC to replenish your power or work location to recharge on those “rainy UK” days when your solar isn’t working…

      But keep in mind that your car battery will experience higher cycle count which will wear out faster.

      Also, V2H or V2G inverters aren’t cheap either.

      1. Luckily, Toyota Mirai comes with the V2H for emergency backup. Can power your home for an entire week!

        1. ModernMarvelFan says:

          Sure it can power a small home “UP TO” a week on the Japanese use model.

          But once I do that even for couple days, I realize that I won’t be able to find more H2 since it doesn’t have the range to make it to the next refilling stations anymore…

        2. floydboy says:

          Catchy moniker you got there. Very ‘right wing’ hyperbolic.

  15. Pushmi-Pullyu says:

    All the news reports about Tesla selling stationary power are for commercial and industrial customers buying PowerPacks, not the smaller PowerWalls. I’d be interested to see a graph of sales over time; hopefully they are increasing!

    Also, battery cells in PowerWalls (and PowerPacks) currently come from Panasonic’s factories in Japan (and elsewhere?). Hopefully, when the Gigafactory comes on line, Tesla will be able to sell PowerPacks and PowerWalls at a price that gives them an attractive cost/benefit ratio outside the limitations of “net metering”.

    No need to repeat what so many others here have said about a PowerWall usable only as an emergency backup not finding many customers. The surprise here is that Tesla tried to sell such a thing, not that it didn’t sell well.

    And only a Tesla basher would try to paint this as an indication that Tesla can’t sell in the stationary energy storage market.

    1. ModernMarvelFan says:

      “The surprise here is that Tesla tried to sell such a thing, not that it didn’t sell well.”

      My surprise is the price.

  16. Sveno says:

    10kw backup power would work well in commercial applications like communications but it would need to be rackmount.

    BTW – inverters are for beginners! 😛

  17. Sveno says:

    Speaking of inverters – I want DC-DC home charging!

  18. HeisenberghtNUTS says:

    And just to put more heat to the discussion (…and to push push me pull you on our most divergent topic 😉 ):

    When will there be enough home storage to make nuclear power plants obsolete for base load supply?

    While I see theoretical solutions for most nuclear power related issues, the main risk will never be eliminated.

    Power plants serve commercial issues and therefor will never run at the most secure configuration.

    Anyone claiming something else should take a look to the measures taken at Belgian nuclear plants right now…

  19. Jonathan B says:

    Wouldn’t a smaller unit’s lifespan be shorter since it will cycle more frequently and cycle count is directly related to degradation? It seems that a 10kw version would not only provide more power but also last longer.

    1. ModernMarvelFan says:

      10kWh version was the “less often used” version for back up only.

      The 6.4kWh version is the frequent used version. I believe/guess that 6.4kWh is based on 10kWh battery derated to only 6.4kWh so frequent/daily use won’t shorten the life nearly as much.

      Similar to what Chevy does with the Volt battery.

  20. Raymondjram says:

    $3,000 for a 6kWh battery pack? This may work for high-rise apartments where the residents need emergency power for two hours, but it is too expensive for most homes. I run an $1,000 5kWh Onan genset for ten hours a day when my power failed, and all my electronics have a UPS on them (my electrical appliances don’t need it). And gasoline for ten hours is still cheap.

    I will wait for prices to drop.