Tesla Reveals Battery Storage Solutions – 7kWh, 10 kWh, 100 kWh (Video)

MAY 1 2015 BY JAY COLE 207

Tesla Outlines Plans Past Just Building Electric Cars On Thursday

Tesla Outlines Plans Past Just Building Electric Cars On Thursday

Elon Musk Announces Tesla Energy - Human "Shouldn't Try To Win The Darwin Award", Get Rid Of Fossil Fuel Energy Generation

Elon Musk Announces Tesla Energy – Humans “Shouldn’t Try To Win The Darwin Award”, But Rather Get Rid Of Fossil Fuel Power Generation

Late Thursday night in Hawthorne, California, Tesla revealed its “missing piece to building a sustainable future,” which the company says puts the world on the road to “enabling zero emissions power generation.”

Tesla notes that the world currently uses 20 trillion kWh of energy annually, which is:

“Enough energy to power a single family home for 1.8 billion years or supply energy to a nuclear power plant for 2,300 years (or launch the Falcon 9 rocket seventeen million times).”

Update:  Watch the entire Tesla Energy presentation by CEO Elon Musk (video at bottom)

The company says that the Tesla Energy products launched today will help to start to wean the world off fossil fuels.

More specifically the company is offering “a suite of batteries” for residential, business and utility use.  Those solutions are outlined below.

As for what was available before today, Tesla CEO Elon Musk was very candid, The issue with existing batteries is that they suck.  They are expensive, unreliable and bad in every way.”

Tesla Energy "Power Packs" Using Solar PV Power Accumulated Earlier Powered The Presentation

Tesla Energy “Power Packs” (Using A Solar PV System) Powered The Presentation

The Tesla CEO said that the first residential units will start shipping in about three months, but that the initial ramp will be slow, as early batteries will be built at the company’s Fremont factory.

However, next year production will switch to Tesla’s Nevada Gigafactory, and things will quickly speed up.

As a special bonus, the whole presentation made from California was done off the grid, via the company’s new utility grade “Power Packs”

The Tesla Model S And The Powerwall

The Tesla Model S And The Powerwall

Powerwall Home Battery

The PowerWall

The PowerWall

The Powerwall is available in two sizes, 10kWh (optimized for backup applications), and 7kWh (optimized for daily use).The cost for these units are $3,500 and $3,000 respectively (to installers) and both can be connect to solar PV or the grid.

We think this pricing says a lot about the raw costs of batteries these days for the company, and bodes well for the future Tesla Model 3.

“The 10kWh Powerwall is optimized to provide backup when the grid goes down, providing power for your home when you need it most. When paired with solar power, the 7kWh Powerwall can be used in daily cycling to extend the environmental and cost benefits of solar into the night when sunlight is unavailable.”

Not enough power? No worries, you can easily double, triple (or go up to 10x) the output with more units together.

The Powerwall not only contains the li-ion battery, but also a liquid thermal control system and software that can receive dispatch commands from a solar inverter.

Conservatively thinking, we imagine that most persons looking to leave the grid (or mostly leave the grid), would conservatively need two or three of the 7 kWh units to achieve that status…and the prerequisite, appropriately sized, PV system of course.

Need More Power?  No Problem

Need More Power? No Problem

The battery can provide a number of different benefits to the customer including:

  • Load shifting – The battery can provide financial savings to its owner by charging during low rate periods when demand for electricity is lower and discharging during more expensive rate periods when electricity demand is higher
  • Increasing self-consumption of solar power generation – The battery can store surplus solar energy not used at the time it is generated and use that energy later when the sun is not shining
  • Back-up power – Assures power in the event of an outage

The Powerwall Home Battery increases the capacity for a household’s solar consumption, while also offering backup functionality during grid outages.

Powerwall Coupled With SolarCity PV Installation

Powerwall Coupled With SolarCity PV Installation

Some specs on the Powerwall Residential system:

Tesla Energy "Powerwall" Specs

Tesla Energy “Powerwall” Specs

Tesla Energy for Businesses

As per the company:

Based on the powertrain architecture and components of Tesla electric vehicles, Tesla energy storage systems deliver broad application compatibility and streamlined installation by integrating batteries, power electronics, thermal management and controls into a turn key system.

Tesla’s energy storage allows businesses to capture the full potential of their facility’s solar arrays by storing excess generation for later use and delivering solar power at all times. Business Storage anticipates and discharges stored power during a facility’s times of highest usage, reducing the demand charge component of the energy energy bills.

Energy storage for business is designed to:

  • Maximize consumption of on-site clean power
  • Avoid peak demand charges
  • Buy electricity when it’s cheapest
  • Get paid by utility or intermediate service providers for participating in grid services
  • Back up critical business operations in the event of a power outage
Tesla Energy For Utility Is Infinitely Scaleable

Tesla Energy For Utility Is Infinitely Scaleable

Tesla Energy for Utility applications – “The Power Pack”

Tesla CEO Elon Musk Introduces the 100 kWh Powerpack

Tesla CEO Elon Musk Introduces the 100 kWh Powerpack

Tesla has also designed large scale systems designed for utilities.  These units come in 100 kWh “battery blocks” and start in total capacity from 500 kWh up to 10 MWh+.

Tesla say the units “are capable of 2hr or 4hr continuous net discharge power using grid tied bi-directional inverters.”

Systems support applications include:  peak shaving, load shifting and demand response for commercial customers while offering, renewable firming and a variety of grid services at utility scales.

No pricing was stated on this product, but the company did offer up what their “Tesla Utility Storage” is designed to do:

  • Firm up renewable generation by reconciling the intermittency of power from these sources and storing excess capacity to dispatch when it’s needed.
  • Increase resource capacity. Utility Storage acts as on-demand distributed power generation, contributing to the overall generating capacity while adding resiliency to the grid.
  • Ramp Control. Utility Storage can act as a buffer while the power output from a large generation source is ramping up or down, delivering power instantly to smoothly transition output to the required level.
  • Improve power quality by preventing fluctuations from propagating to downstream loads.
  • Defer costly and time-consuming infrastructure upgrades.
  • Manage peak demand by deploying power within seconds or milliseconds.
Tesla Energy Utility Design

Tesla Energy Utility Design

Those interested in having a home Tesla battery can reserve units now at Tesla’s new “Powerwall” mini-site here.

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207 Comments on "Tesla Reveals Battery Storage Solutions – 7kWh, 10 kWh, 100 kWh (Video)"

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And now, batteries are sexy.

In the past, I’ve seen some pretty sexy energizer bunny costumes.


Uh oh…is kdawg a furry? 😉

I was going to link a pic, but NSFW. Google is your friend 🙂


Sort of gives a new meaning to putting on the dog.



I was liking the news release until I got to the power output of the 7 kWh system… 3.3kW peak, 2kW continuous. Ouch. That limits exactly what is used in a backup scenario for sure.

I was hoping that with a purpose-built unit like this (and associated cost), there would be at least a 7kW output from a 7kWh unit.

Also just noticed it’s just a battery… They don’t include an inverter. Oy! I guess I set my bar for expectations far too high.


Right! If an EVextend.com inverter kit can provide 1.5 kW and people have two plugin cars in their garage… 🙂

Really curious how they thermally manage the power wall, surely it would not be installed on a Southwest facing wall in Arizona.

Alonso Perez

It has a liquid cooling system.


I just got my quote back for backup battery for my grid-tied PV system from my local solar installers. To get 7 kWh usable and 2 kW continuous, it would cost me $8k with an inverter. I am asking to get the cost broken down for me.


OMG how could you Anglos oppress the whole world, when you don’t even realize that you can simply combine up to 9 of those “Powerwalls” if you need more power?

What is the actual total size of each pack? 15, 20kWh’s? I’m guessing they are both 15kWh’s but the 7 one has a larger buffer than the weekly 10 battery…


Mr EnergyCzar – go to http://www.teslaenergy.com – the specs are there. They are 7kWh and 10kWh units. Power output is at 2KW continuous.


3500 bucks for a PowerWall Pack.. You could just get this and it would pay for itself in about a year… sign me up!


I think you should check your math before putting down a deposit. 🙂


depends what you pay annually for electricity and whether or not you already have solar PV and what their annual contribution is


If Fabien is expecting a Tesla $3,500 Power Pack to “pay for itself in about a year,” he will be bitterly disappointed.


Assuming $0.20 per kWh and using exactly 7 kWh’s per day every day for a whole year,

$0.20/kWh * 365 * 7 kWh = $511 per year. payoff will take 7 years.


My interest is in the battery backup… $3500 + inverter is less than the cost of an equivalent generator plug fuel supply for me.


I pay 50 cents per kilowatt hour during peak hours. I see payoff in 4 years


Perhaps a scenario could be to use the Powerwall during peak hours and grid energy overnight during off-peak?

Mainly, I too am interested mostly for power backup. Grid-charged, without any solar panels, it still would be an interesting proposition instead of a diesel generator and storing all that diesel fuel.


What exactly is the interface? You don’t seem to get any AC to DC or DC to AC inverters and the battery box needs 350 to 450 volts DC.

How does it connect to the Solar Panels, your current Inverter and the Grid? What are the extras?


Based on the datasheet perhaps it does have a DC to AC inverter since it states it is single phase compatible. So that leaves open the question of how it gets changed since they say AC to DC inverter is not included.

Alonso Perez

It gets charged DC to DC. It’s meant to be charged from solar panels, which are DC.

I’m more concerned with the low power. 2.0 kW is two hair dryers. You can easily exceed that even in a small home. So it would take special effort to go off-grid with just one of these. You’d need about three.


I don’t know if you can say “it’s meant to be charged from solar panels,” when Tesla states that one of the benefits to the customer is load shifting, which would charge from the AC grid and require an inverter.

“Load shifting – The battery can provide financial savings to its owner by charging during low rate periods when demand for electricity is lower and discharging during more expensive rate periods when electricity demand is higher”


Not sure it is that simple. My panels don’t output 350-450 and even if they did it would be more power than the battery can take. That means you need to have the battery pack DC inputs in parallel with the normal Solar Inverter so the excess power goes to the Grid.

A normal Solar inverter tries to keep the voltage from the panels at an optimal value (tracking) don’t know how adding the battery pack in parallel effects that.

I think I hear/read you need a “supported” solar inverter. So anyone with a current system might need to upgrade their solar inverter.


Alonzo, a hair dryer runs for 3 minutes, you cannot compare…
Don’t you think that Tesla would not sell ill powered batteries for a normal usage in a normal household??


I mean a 2 kilowatt hair dryer does not use 2 kilowatts for an hour but for 2 or 3 minutes.

A hugely more hungry clothes dryer use 3.3 kWh, big difference!

Alonso Perez

Honestly the info is too sparse. I would expect to see block diagrams for typical installations. I’m saying you would need special power management to go off-grid with just one of these. It’s doable but not practical unless you are a power geek.

So I am guessing the one-pack scenario is basically to balance demand, not to eliminate it altogether, plus to act as a backup in case of power outage.


Probably more accurate info would ruin the theatrics of the announcement as it would frame the use of those products in a much narrower niche as what is suggested by Tesla I am affraid.


Going completely off grid isn’t practical in general. Look at some “off grid living” websites, you’ll quickly discover that (other than lots of good advice on solar power systems) they are mostly about how to live with a -lot- less power.

To aim specifically at the market for off gridders would be rather foolish for Tesla. That market is much too small.


That small market is plenty for Tesla. It includes half of Australia, who pay 15c/kWh *average* for distribution and transmission alone.
Add in profit, generation, and environmental tariffs, and you’re up to 28c/kWh average there.

Then you have people around the world using TOU pricing, commercial customers looking to cut demand charges, remote homes paying 30c/kWh+ if they want a grid connection, and people wanting to go offgrid for personal reasons.

Up to 10M packs per year demand will be easy, IMO.


(10M packs/yr in the long term. 1M packs/yr market in the next 5 years, IMO.)

Turbo3, their summary specifically lists “DC to AC inverter not included” under the “Installation” section in the Specs image above.


Spec sheet implies 48vdc input bus, most likely post charge controller. But it’s not clear.


If you look through the window of the Tesla Model S in the picture, you’ll see an inverter manufactured by SolarEdge hanging on the wall.


So, there are two Models:

Powerwall comes in 10 kWh weekly cycle and 7 kWh daily cycle models.

10 kWh $3,500
For backup applications

7 kWh $3,000
For daily cycle applications

My question is: Can you use the 10 kWh of juice everyday? Why does the big model say ‘weekly’?


Some how the systems are tuned for either bulk storage with only infrequent (weekly?) discharge (Backup app) or Daily cycling to shift energy during the day. That is the way I read it.


I noticed that the website says it is 10kWh “weekly cycle” . That does not sound good. That is only 1.4 kWh per day. Enough to maybe power a single refrigerator.

Dr, Miguelito Loveless

Weekly discharge means it is optimized as a backup system to cut in when you lose power. It’s battery life usage is predicated on being cycled once a week for up to 10 kWh. The “daily cycle” system can be used every day, and provides up to 7 kWh.

Here’s more specs. At this Voltage you should be able to DC charge a Tesla if they make it an option.



Voltage is not a concern. DC-DC converters are very efficient (>98%) and relatively cheap these days.


“92% round-trip DC efficiency”. That should be music to the ears of DC-chargeable PHEV owners. I assumed <85%, thinking inversion losses, would make solar-home battery-car battery a tough go. Now, I appreciate more the virtue of keeping the whole path DC.

no comment

i’m not sure that i understand this: a lot of cities have moved to net metering, which means that when your solar panels generate excess energy that extra energy goes into the grid and you get energy credits that you cash in during the evening or other times when the solar panels aren’t generating electricity.

so with net metering, the only use that i can see for this is house-wide battery backup.


I am on net metering and would not mind charging at night and sending back to the grid during daytime peak rates. Buy low sell high.


Exactly, buy low sell high. Over the course of a whole year, this adds up. Combined with a PV array, it’s even sweeter since you are selling back even more peak sunshine-kwhs during the day.


It doesn’t seem like you would make any money unless the spread between peak and off peak electricity was really huge.

If the spread is $.20, then you would make only $380 per year and $3,800 over ten years. ($.20/kWh x 7 kWH per day x 365 days x 90% AC to DC inverter efficiency x 92% round-trip DC efficiency x 90% DC to AC inverter efficiency = $380.80 per year)

Is the round-trip DC efficiency from the specs a measure of how much energy is lost from putting energy into a battery and pulling it out?


Correct me if I am wrong, but your calculations seem to show – for that price you would have installed a clean running, quiet, no maintenance back-up generator which pays for itself after eight years.


Assuming an average price difference of 20 cents per kWh, which seems rather high imo. My opinion is therefore that the unit will not pay for itself.

But that doesn’t mean it isn’t a very sexy and desirable addition to any home 😉

Robb Stark

For Southern California Edison super off-peak is $.11 per kWh and $.36 per kWh Winter and $.46 kWh for peak with a basic monthly charge of $.93.

Peak rates can go down to $.35 and $.25 if you pay a monthly $16 fee.

I would save about $1k per year.


That ginormous spread in rates will probably be significantly reduced soon. California state energy regulators recently proposed major changes to overhaul electricity rates.



I liked the high peak rates with solar, I made money. Now they changed the peak time to 2pm until 8pm just to stick it to the solar owners.


Don’t fool yourself the five member public utility comision in California is in the pocket of the big electric guys. We pay about 3X the national average for electricity.



You wouldn’t have a 24/7 backup generator if you planned on buying electricity at night and selling during the day. Your solar panels wouldn’t be charging your Tesla battery during the day, and it would be empty by the evening. Since your Tesla battery would be empty in the evening, if a blackout occurred in the evening you’d be in the dark until morning hoping it’s not going to rain or snow that day. For the Tesla battery to function as a reliable backup generator, it would need to have a high SOC in the evening.

Also, more than eight years when you factor in the cost of the inverter that you must purchase separately, and the cost of the electrician to install the system.

After ten years the batteries will also have been cycled/discharged 3,650 times.

If the spread is $.20, then you would make only $380 per year and $3,800 over ten years. ($.20/kWh x 7 kWH per day x 365 days x 90% AC to DC inverter efficiency x 92% round-trip DC efficiency x 90% DC to AC inverter efficiency = $380.80 per year) I don’t think this math isn’t quite right. Here’s my attempt but I could still be missing something. At 90% AC to DC and allocating half of the 8% DC to DC loss (92% efficient) to the charging side, you’d pull 8.14 kWh to charge the 7 kWh pack. Then you’d sell back 86.4% of that (90% x 1/2 of 92%) which is 6.04 kWh. So you’re pulling about 8.1 kWh and returning 6 kWh. To calculate the profit from this you need to know the spread and the base price, since even a nice spread isn’t going to help if you’re losing 2 kWh of high priced energy. Using Robb’s reported SoCal numbers of $0.11 base and $0.46 peak (which is probably best case scenario) you’d buy those 8.1 kWh for $0.89 and resell 6 kWh back for $2.72 for a profit of $1.83 daily or $667 per year.… Read more »

Dan, I think you calculation is more accurate than mine.


I think it is a bit naive to think that cheaper batteries will allow to save $ by selling sunshine Kwh into the grid. If that happens in some sort of noticeable scale the utilities will just gradually reduce the purchase price of those Kwh. I would rather see this as good news in a long term trend where solar and wind power can effectively replace “dirty” energy.


People who think they’ll sell from the panels at peak rates and buy at off-peak rates forget that, if panels become more than a blip on the radar, the utilities will be paying wholesale and selling at retail. You’re not going to make money. You’ll see.


Utilities are a heavily regulated industry. They don’t get to choose what they do. Right now, net-metering is the deal (you loan your PV electricity during the day and they pay it back at other times in kind such that rates are not involved).

Net-metering will eventually have to change as it becomes too popular. But the regulators will get to decide what is next.


Power companies will specifically ban this, if not already.


Southern California Edison is trying to ban olar. They changed the peak rate times to 2pm until 8pm so that they arent buying all the solar at peak rates since the bulk of the solar stops about 5pm.


net metering isn’t ideal as the utility company buys back off you at wholesale (not retail) rates, so in short, you’re still making a financial loss on excess electricity generated.

With the powerwall, that excess energy is stored for later rather than sold at a loss, so you’re actually saving money.

John in AA

It depends on your utility’s net metering tariff. Here in DTE-land (and maybe all of Michigan? I don’t know) the utility buys back from you at retail. In that scenario, I don’t see a “business case” other than as a whole-house UPS.

Doug B

The same cost to buy and sell model of net metering is changing as rapidly as utilities can do so. They need to recover the line maintenance and system costs that are included in your kWh pricing, and with standard net metering they do not as they give it back to you.
In the next few years you’ll see more and more utilities moving to a buy and sell model where you pay to move the power out from your home but get paid for the energy.
This system will then work best by saving your solar energy to avoid selling it at low cost and buying back higher. TOU rates will complicate this, but its all pointing to grid as backup to your home power microgrid.

John in AA

Yes, exactly, point being that the economics depend strongly (almost entirely) on the specifics of the tariff.

I wouldn’t buy one of these today, because the tariff available to me makes it unnecessary. If DTE changes the tariff (and is allowed by the PUC to do so) then I’m glad to know the option is available. It will also be interesting to see how the competitive pressure affects how utilities choose to play the tariff game.

Interesting times.


Doug B, I think you nailed it. Spot on.

Willem Post
Sven, Some folks are claiming one could buy low-cost energy during off-peak hours, store it in a wall-mounted, TESLA battery pack, and use the energy during high-cost, on-peak hours. Here are some calculations. At 90% AC to DC inverter efficiency, and allocating half of the 8% DC-to-DC loss to the charging side (the TESLA unit has a round-trip DC-to-DC efficiency of 92%, per spec sheet), it would take 7/(0.9 x 0.96) = 8.10 AC kWh of off-peak grid energy to charge 7 DC kWh into the unit. During on-peak hours, one would get back 7 x 0.96 x 0.90 = 6.05 AC kWh to use in the house. A big loss of energy!! The INSTALLED cost of the 7 kWh TESLA unit = $3,000, plus S & H, plus contractor markup of about 10 percent, PLUS $2,000 for an AC to DC inverter, PLUS installation by 2 electricians, say 16 hours @ $60/hr.= $6,500. In Southern California, base rates are $0.11, off-peak, and $0.46, on-peak; which likely is THE best-case scenario in the US. The 8.10 AC kWh, off-peak, would cost $0.89. The avoided cost of 6.05 AC kWh, on-peak, would be $2.78, for a profit of $1.89/day, or $691/yr.… Read more »
Alonso Perez

There are two business cases I can see, independent of metering structure:

1. Whole house UPS.

2. Off-Grid Solar

#1 can be hugely appealing in many areas subject to storms that down power lines regularly. Certainly worth $3500, or more. If power outages are rare in your area, then there is no appeal to this at all. I’d get this in suburban areas of south Florida, Florida Keys, other Gulf areas with limited access, parts of the country where ice can down power lines.

Some people have special power needs. Some drugs need refrigeration for example, or they might have an elevator because they can no longer use the stairs. If they can afford it, a whole house UPS is a a cleaner option than a generator, and requires less maintenance.

#2 requires, in most cases, more than one pack. It has interesting implications for remote sites that are now too far from an electrical connection. Even several packs are still cheaper than running a line for a mile or two. It will also appeal to those who wish to go off grid out of ideology, though that is a small number of people, they will provide early demand.


$3,500 is a wholesale price for just the battery. The retail price for an 11 kWh generator is $3,000. Cost it out, and Tesla’s “solution” is not only much, much more expensive, but considerably less powerful when it comes to the output needed to be an effective backup.


Of course the equivalent generator is cheaper. But it’s a lot noisier, stinks, a bigger fire hazard and is dependant on fossil fuel. Also can’t utilize a PV setup. It’s a no-brainer..


SCE buys back at retail


RE: “energy credits”

..or SRECs, are in a few states (not CA) where you not only get net metered, but a side benefit that will continue to accrue to PV-battery users. I say that assuming that if a home solar user can get SREC credit for watts they do not physically send to the grid, they can still get these credits if going to batteries.
<dozen states have them:

DSIRE is a great site, if you want to noodle utility policies. The SRECs can price $.10-.20 / kwh. I think of it as an economic benefit that is similar to CA users being able to arbitrage big peak spreads, and reduce consumption on their commonly tiered rate programs (the first, highest priced, at the margin kwh's).


The required inverter will still add a good bit of change to those sums.


I think the idea is that if you have solar, you might already have a suitable inverter.

Otherwise, you’re right. 🙂


A 3 kW solar inverter goes for around $ 500. The inverter for this battery can be simpler because it doesn’t need a maximum power point tracker. So the extra cost will not be that much I think.


A 3KW Grid Tied Solar inverter with MPPT for $500? Care to share a link?


The OmnikSol 3k TL2 or Hosola 3k TL or quite a few other solar inverters currently trade for about 500 euros or so, that is including 21% VAT and with a receipt.

Comparatively, the SMA Smart Energy 3600/5000 are quite a bit more expensive at 5000 euros with just 2kWh of storage.

It also uses a high voltage DC bus (150 Volts) so that the normal PV inputs can use it to feed into your grid at home.

What’s important to note is that these devices generally work in a hybrid mode. It’s not a UPS, most will disconnect from the grid when it fails, although some support island mode as well.

For example, if you request 2000 Watts, and the solar only does 1000, the inverter will then feed in another 1000 Watts from the battery for a net value of 0.

It works both ways simultaneously through the day. It’s not meant to power your house solely. If you request 5000 Watts, it will momentarily do 3k from the battery and fetch the other 2k from the grid.

The 100 kWh infinitely scalable “battery blocks” are potential money makers depending on the price per kWh and number of cycles if cycled daily?


This is the question left alone, I think. 7kwh @$3,000, really doens’t do the job for a house that might use 30-50kwh/day. Others can be criticized for modeling ~16kwh, in their more optimistic outlook for grid-tied PV-battery. When you grow the storage level, maybe to 20-30kwh, does this implied $428/kwh price drop? How much? I hope 7kwh isn’t the total storage spec, at this price.

Lastly, the inputs to know what’s worth what, against your situation are changing. Net metering is trending from retail price to wholesale, demand charges and fixed charges on solar are being levied in greater frequency, and the more progressive policy states are deliberately allowing higher prices (to motivate efficiencies, etc.) Some of these help make the PV-battery argument. Some hurt.


The average U.S. household uses 31 kWh a day. And if you look into the average, you find that only 61% of households are single family. The rest are attached townhouses, mobile homes, and apartments, just about all of them using a lot less than the average.

Therefore, the backup capability of a Tesla battery is something of a joke. I honestly wonder what in hell the company is thinking, unless maybe they just want to keep the name out there with another press release.

You don’t understand. Most home solar power systems are not intended to provide all the power for the home, 24 hours a day. They just provide power during the period when buying electricity from the grid is the most expensive. Electricity at night, during “off-peak hours”, is generally a lot cheaper. You shoul look at a home solar power installation from the viewpoint of a cost/benefit analysis. Installing solar panels is expensive. There’s a lot of benefit to installing enough square footage of solar panels to offset the energy demand during the hours of the day when electricity from the grid is the most expensive, which fortunately mostly overlaps the hours when the solar panels generate the most power. Beyond that limit of square footage, it makes a lot less sense to buy more solar panels. The cost/benefit ratio drops sharply. That’s why very few solar power installations will actually provide all the power a home (or commercial building) needs for a full 24 hour cycle. That said, 7 kWh does sound like a rather small amount of energy for daily use, especially if you only cycle 80% of that. But I suppose it might be sufficient for a small… Read more »

An apartment dweller isn’t going to have the panels to begin with, much less the battery. The time-shifting idea just doesn’t convince me at all. If you saved 10 cents per kWh by time shifting, I just don’t see how you’d ever pay for the rig once you’ve included all the costs, especially given that it doesn’t seem to last for more than 10 years. I’m genuinely puzzled over who’d really want to buy the thing.


Damn…. $3k? I was skeptical but at that price point, I’d be tempted to install one myself just as a lark. I need to learn more about the interface and how it is coupled to the home.


I agree with that. I wish they had some typical examples of the hardware showing how it is all connected together (solar Panels, Solar inverter, Battery, Grid/House).

Now everyone can afford a Tesla.


That is a brilliant observation, however if that is your home-produced solar electricity or the grid is down that 10 kWh would be worth a lot more than $1 to you 🙂


that was meant for Three Electrics down in the thread 🙂


Put the 7kwh pack hooked up and on the roof of a volt or leaf, now that sounds fun 🙂


Or, mount one or two on a trailer, and you have a 10 / 20kWh range extender.
Probably as a rental, as otherwise the RoI would be pretty bad…
I wonder how easy it would be to do this…

Great idea!

Add two 10 kWh packs to a LEAF and you double the range for $7k. The PowerWalls even look pretty aerodynamic already.


Or buy three of them for an EV conversion with a Tesla pack. You’d have some trouble with peak power, which they probably limited intentionally so people wouldn’t do that and/or because a home shouldn’t require that much peak power.

But, the price shouldn’t be any different from them to offer this kind of EV conversion battery in the future. I can hope (but again, I guess they wouldn’t bother though since there’s basically no market for that).


Power is probably limited by heat. the radiator is probably very small

Ocean Railroader

The Tesla batteries used in the model S and most likely this battery pack are double the energy density of a Mitsubishi i-miev battery pack. This means if you took the battery pack out of the i-miev and put this in you would double your range. This is also 50% more powerful then a existing leaf battery pack. Now if this pack is $3000 dollars that is well with in reason of battery swapping s existing low density EV battery.

Now if Tesla does upgrades their cells to use say 10% or 20% more energy density it will only make battery upgrading more tempting.

mr. M

More powerfull than leaf??? At 3*7=21kwh you geht only 6 kW power. You know that the leaf has over 50kw power??? Also you need around 20kw permanent for driving 70-80mph. Not good for cars…


Nissan say’s Leaf is good to boost up to 90kw total, wich make sense since the motor as 80 kw rating and can be floor anytimes. (As most Leaf driver do with pleasure(


I wonder how important this new line of products is to the off griders. I just had a quick check on the net and could find that 1,2 Kwh of deep cycle batteries (12V 100Ah) are about the same price as this (circa $350 for 1,2 Kwh, at least here in Europe where everything tends to be more expensive).
Now I guess those batteries have more deep cycles potential than the existing technology yet available to off griders.


If by “deep cycle” you mean deep cycle lead-acid batteries, then I’m quite surprised that the cost is approximately equal. In the home storage application, li-ion is said to last about three times as long as lead-acid. Or to put it another way, about three times as many cycles before they need replacing.


OK , so those new batteries could effectively be much cheaper than existing lead batteries currently available to off griders. It will be interesting to know number of deep cycles those batteries can sustain.


Both have a 10 year warranty so at least 52×10 for the 10kW and 365×10 for the 7kW. Pay more and you can extend another 10 years.


People have to stop and think about off-gridders. These are not generally the kind of folks with extra thousands to spend on Tesla’s approach — to put it politely.


The tiny percentage of people actually living off-grid are not going to make a significant impact on whether or not Tesla can make a profit at this.

The truly poor living off-grid use discarded, used deep-cycle lead acid batteries that have reached the end of their useful life powering a golf cart or whatever. Tesla isn’t going to lose money by not appealing to those customers, since they aren’t in the market for buying new batteries anyway.


Uh . . . many off-gridders are very wealthy people building very fancy remote cabins with all the modern conveniences because that is something you can easily do these days. It was much harder in the past but now with cheap solar PV . . .


Do you mean the nominal Wh rating for lead-acid batteries or usable because lead batteries have quite a narrow usable charge level.


Isn’t it Li-Fe batteries that are used with solar and micro windmills?


Lithium-iron-phosphate is a competitor. Everyone is just getting started on this technology. This is the first commercial home unit I’ve seen, but it may not be first to market.

Quoting the article: “We think this pricing says a lot about the raw costs of batteries these days for the company, and bodes well for the future Tesla Model 3.” The 7 kWh unit, engineered to be cycled daily, costs $3000. That’s $428.51 per kWh. Of course, that’s the price, not Tesla’s cost, and obviously includes some profit margin. But even still, that’s far from cheap, so I’m puzzled over the comment that this “bodes well for the… Model 3”. By comparison, a Tesla spokesman said that the Model S’s battery pack was about a quarter of the cost of the car. Taking the average selling price of a Model S, which was about $95,000 at the time that statement was made, that puts Tesla’s approximate cost at (95,000 / 85 / 4 =) $279.41 per kWh. That’s a heck of a lot cheaper. If Tesla’s per-kWh cost was the same for the home storage unit as for a Model S, then they’re making 53.36% profit on the home storage units. I don’t find that high a profit margin likely. Much more likely is that it will cost Tesla significantly more per kWh for these home storage units, at least… Read more »

I don’t think your comparing apples to apples here. The Model S pack cost you’re using is just the battery. The home pack is covered in packing, insulation, cooling mechanisms, control electronics, cabling, man hours to assemble it, equipment expense recovery costs, and profit margin, not to mention they are built for very different situations. The home pack doesn’t have to be designed for regen braking or high acceleration output for instance, charging is much more consistent and from a single power source, not from random superchargers that may or may not be damaged, much less stress is put on the battery in the home instance. The battery in this pack is less expensive per kWh than a Model S battery. How much is very hard to say without more information, but I would guess more along the lines of $225-$250/kWh. Which would put the pack itself in the $1750 range before all the other stuff is added on, which only leaves $1250 per pack for everything else I mentioned and to make a profit.


The Model S battery pack includes a liquid cooling/heating system, as well as wiring, a fuse for every individual battery cell, packaging, and a very strong, rigid case. It’s a lot more expensive than just the cells contained -in- the pack; perhaps closer to twice that cost.

In the long run, I would expect the home storage unit to be cheaper per kWh, because it’s used in a less demanding role. For example: The power output for a Tesla Model S battery pack can be very high, -much- higher than the typical residential power demand. That means the Model S battery pack needs a much more robust cooling system.

And yet, the 10 kWh is only slightly more than the 7 kWh. Which indicates cells are only a part of the cost, and possibly not even the biggest part. It’s called “scalability,” as many of the costs (“nonrecurring”) apply to the overall design, including both the 7 and 10 kWh designs. By design, I include testing, certification, and numerous interfaces, which are why homeowners haven’t thrown together their own buckets of cells already.

Much more likely we can hope your blanket statements will come down over time.


The small price difference between the 7kWh and 10kWh is probably because the “7kWh” daily cycle pack actually has 8-9kWh of cells that are under charged and under drained to take a daily beating.


$428.51 per kWh seems pretty good to me. In addition to the raw cell cost, there is the thermal system, the software, the case, the NRE, the profit, etc. So the raw cell cost could be in the $200s/KWH.

Before the announcement, various stories were suggesting a price of $10,000.00. So the $3,000.00 price came in surprisingly low to me.

I really need to learn more about how they plan to hook these up. I have a microinverter based PV system, so how would that integrate? Basically the same as a system with no PV system I suspect. And how do they hook into a home with no PV system? I want manuals! Lots of manuals!


I think a better way to compare is that the price difference between a base 60kWh and base 85kWh Model S was $10k, that means $400/kWh, which includes a healthy margin which Tesla gets on all its options.
On the solar storage side, it’s difficult to gauge what the non-battery pack costs are. You can’t take the difference between the 10kWh and 7kWh models, because I’m not convinced the 7kWh pack only has 7kWh of cells in it. But to look at the total cost of the 7kWh unit and see that that is $428/kWh (almost the pack only cost on the Model S) shows significant cost reduction.


I don’t think we can take the difference between the price of the 60 kWh Tesla Model S, and the 85 kWh Model S, and conclude anything about Tesla’s cost of making the battery pack. That’s confusing cost and price.

However, I’ve seen many people make the same calculation, so you’re in good company. 🙂


I am really disappointed with this, it’s just a battery, or rather a battery pack probably made from the scrap bin of the model s factory. I was at least hoping for an intergrated inverter maybe even v2g compatable with the S. The price is good but this could have been so much more.

There’s only one thing for it, $7k’s worth of batteries + a dc boost converter and I’ve go me a 20kW leaf Rex for occasional use, pass me the tin opener.


Well, they didn’t provide much detail so perhaps some of that will be added in due time.

I think this is largely just to create some more Tesla & Solarcity hype. And to show that they will have good reason to build the gigafactory beyond just Tesla cars.

And the market will be real assuming they do push prices down low enough.


Woah thats cheap, i buy one or two :-).


now let’s put one of those 100kwh battery in our EV’s that would be nice.

“Get paid by utility or intermediate service providers for participating in grid services”

Cue Bill, the Buffalo broken record!


$35,000 – Gets you ten of these and off the grid permanently.


Dr, Miguelito Loveless

The catch seems to be, “Reserves yours today”

Tap, tap, tap.

“Thank you. We will contact you when the Power Wall is available in your area.”

So, since I don’t have a Solar City in my state, I am guessing I will be waiting a LONG time.


I signed up and I’m just a mile or two from Tesla HQ and just a few miles from Solar City HQ. So I hope to hear from them.

Of course, they probably won’t want to sell to me because I just want to buy it and install myself. I’m a tinkerer that likes to do things hands-on.


Maybe not so long since you don’t have to use solar to benefit from the backup batteries.


What does “(to installers)” mean?

Wholesale price, I’m guessing.


So, what will they really cost?



Ocean Railroader

This could be great if you live in the Bahamas were you have to pay $500 dollars a month for power due to them having to important Dino juice to run the generators.

I could see myself buying one of these things if I ever get solar power. This would be great in that the price doesn’t sound to bad.

I think there is going to be blood in the coal industry now.

Three Electrics

Costs $3000 to store $1 worth of electricity.


That is a brilliant observation, however if that is your home-produced solar electricity or the grid is down that 10 kWh would be worth a lot more than $1 to you 🙂


Hopefully you mange to get at least two charge cycles out of it. Then I’d only cost you $1,500 to cycle through $2 worth. 🙂

Doug B

In Colorado its $0.70 worth of energy stored, and assuming no net metering (which we have) you’d have to cycle it 4,286 times to get to payback, that’s storing and using 30MWh of energy. Yikes!

mr. M

Yet it say you can use it for 7kwh*10*365days=25550kwh or 25.5 MW. Not that far from break even…

mr. M

25.5MWh of course.

Alonso Perez

It’s worth a heck of a lot more than a dollar the day the power goes out. In places where that happens often, this is an easy buy.

But yeah, if your grid is reliable and you have a good tariff structure, it doesn’t make sense yet.

Yes, $3K to store a little more than $1 of electricity (using a nationwide average). And THAT is a breakthrough price. Yes, batteries have been expensive and that’s why no one uses them. But things are changing. That battery price is dropping. And in many places, the electricity is more expensive. So on the NorthEast coast, California, and Hawaii, electricity costs more like 20 to 40 cents per KWH. Plus the price of solar PV has dropped by some 70% in the past 5 years. Between higher grid electricity costs, really cheap solar PV, and cheaper batteries . . . there is a fundamental shift about to start. I’m on the forefront . . . I live in California with high electricity prices, I have GREAT solar resources, I had the ability to self-install my own solar PV system, and I had the money to buy a (cheap) EV. And due to my advantages, I’ve created a ridiculously economically advantageous system for myself with a cheap solar PV system that provides all my electricity and transportation fuel for free. I realize that I am an anomaly but more and more people will be able to save money on electricity &… Read more »
I am failing to see the appeal of battery storage to people with panels — who, by the way, produce only 0.45% of the country’s electricity, less than half of what’s generated by burning of wood and wood products. http://tinyurl.com/uselecgen If you’re grid-tied, you already get a great deal. You feed electricity back to the grid, and exchange it 1:1 for electricity when your panels aren’t producing. In effect, the grid is your battery, and it’s free. The tiny group of back-to-the-land types who aren’t on the grid? I doubt very many of them are going to pop for Tesla batteries. Those people tend to use very little juice, and already have deep-cycle lead-acid storage. If this is Tesla’s business plan — to sell pricey batteries to one group of people who don’t need them and to a much smaller group who can’t afford them — well, I’m not seeing how it’ll work. At utility scale, big lead-acid-antimony batteries are just around the corner. We don’t have the cost numbers yet, but they are simple and are likely to be quite cheap. http://tinyurl.com/lqdbatt Methinks Elon Musk is going to miss on this swing. For Tesla’s sake, let’s hope they’re not… Read more »
Residences are not going to be a big market. Some will want them. If you can eliminate black-outs for $3K to $5K, a lot of people in California will get that. That’s pretty small change in comparison to the multi-million dollar home prices. But it will be businesses where the bigger market is. They are often subject to steep ‘demand charges’. Demand charges that they can avoid by installing a battery. And yeah, net-metering is nice. But if you’ve read the energy news lately you’ll know that utilities are no longer happy that they made that deal and they are are trying to kill off net metering as hard as they can. Things are going to change. (Who knows how but things won’t remain as is forever.) Hopefully we move to more of a time-of-use market-based system. And at that point, the use of storage starts becoming more important. It will be best for all to reduce waste. And that means charging high prices when there is high demand and charging low prices when there is low demand. And THAT will create a market for batteries. You can’t just look at the current regulatory framework . . . that is… Read more »

You are correct in pointing out that for a lot of people who have a home solar power system, it won’t pay to install a battery pack.

But some people would benefit, depending on their circumstances. For one thing, having a battery could even out the power fluctuations on a partly cloudy day.

But I think there is a more common scenario where buying a battery pack might make sense: Googling “off peak hours electricity”, the first hit is 9 PM to 7 AM. A rooftop solar power system will stop generating near-maximum power long before 9 PM, but the home owner wouldn’t want to start buying power from the grid until 9 PM. A battery pack could be useful to bridge the gap between, say, 4-5 PM to 9 PM. There’s a similar window of opportunity for early morning hours during winter.


Yes, the 5pm to 9pm slot is a big problem in California. Google ‘electricity duck graph’ and you’ll see the issue. All of the solar PV electricity goes away just as everyone comes home, turns on the TV, turns on the AC, and fires up the stove to cook dinner.

Right there is where we need batteries. They would be best on the grid level but consumer level helps too. Right now it is largely handled by cranking up existing plants and turning on peakers. But it would be much more efficient if we had battery storage to handle that evening peak.


I have no doubt that you can come up with scenarios where you can save a few bucks by time shifting, but you’ll never even come close to paying back the cost of the battery, equipment, and installation.

And if it’s backup, you simply get a natural gas powered, whole house generator. Those are $3,000 retail. Either there’s something significant that I’m missing, or this move by Tesla is just strange. I’m picking Door #2 for now.


Well it really depends on what the cost is doesn’t it? Tesla has openly said they are trying to push cells down close to the $100/KWH price level. If they get down there, that really changes things.

And the installation . . . well if you are already getting a solar PV system installed, adding a Tesla battery is probably just an hour or so of more work.

I agree that the residential market will be small initially. But there will initially be some early adopters that just want it because. We “sillycon valley” people can be like that with new technology that we find interesting. There will be people that value having a back-up system that lets them continue having electricity even if there is a local black-out. There will be off-grid applications.

Only when the price gets low enough or the incentive systems are right will there be much larger adoption.


Well . . . $1 worth of electricity is about what a typical house uses overnight.


If they are giving us the real story, and both packs are the same price, size, voltage, and weight, then they are using the same physical size and number of cells in each pack. The 10 kWh pack is “energy” cells, and the 7 kWh pack is “power” (higher C rate, lower storage capacity) cells. This is just what you see in e-assist battery packs. Panasonic, and Samsung sell this same cell format for e-assist packs.


For me, the big news is that everybody selling cells, and packs to the DIY EV crowd just had a heart attack! Tesla is now selling a pack for less than you can buy the cells for.


Tesla is now a battery company


Can Tesla they sell batteries in their company stores or will some states require Tesla to sell batteries through dealers? 😉


Well put…


I think the ‘battery company’ bit is overdone. Batteries are just a necessary technology for accomplishing their real goals . . . selling emission-free cars and helping build a green energy system.

The battery biz is a near zero margin biz that they are going into on a massive scale in order to have low cost batteries which enable solutions like electric cars and off-grid homes.

Anton Wahlman

What is competition for this product, and what kind of profit margin — if any — is associated with this product?


can i hook it up as an aux battery in my EV?

2013 coda


1) I already have an inverter for my solar system. Do I need a second inverter for this battery or can it be hooked up to my current inverter?

2) $3,000 cost to an installer. Does that mean I will be charged an additional mark-up? Also, what will it cost to install? Basically, what’s my out-of-pocket cost?

energy matters

MANY additional costs here:

– 350-450 volts is equivalent to a string of solar panels but is NOT a safe level voltage for self install or telecomm use. The high voltage reduces the wire size though helping to reduce weight.

– Only straight solar inverters operate at these voltages, most off grid units run in the 48V-60V range as that is a safe voltage.

– There;s no mention of the control CPU that makes all these magic things happen.

– No mention of the compatible inverters nor design and installation documentation.

– you WILL have to purchase an inverter. Expect $5K+ depending on your size.

– Expect a $1K metering interconnection from the utility.

– Expect $at least $1.00/watt for the install labor (based on your solar installer’s rates).

– Be aware in CA that the utilities have been in strong “harassment” mode on batteries being grid tied to the point of denying operational permission to connect ( which of course drives you to go off-grid sooner).

Many missing details.

It terms of single family home in New York where we sometimes lose power for a week how does this battery compare to a generator as electric supply backup. Would it run a boiler hot water heater and lights for a few days?


For a week? I’d stick to the generator.


Average energy consumption for an American single-family house is about 30 kWh per day, altho of course consuption can vary a lot, for example by whether or not you’re running an air conditioner, and how big the house is. When figuring how many of these Tesla units you’d need, remember that you don’t want to use more than about 80% of the full capacity of the pack. Fully charging or discharging the pack will age it prematurely.

Batteries are not a cost-effective solution for a power outage lasting a day or more.

Ocean Railroader

I could most likely get away with using this during the night. In that between 12.00AM and 7.00AM most houses use the least amount of power.


$350/kWh, and if it’s lithium ion you’d better not use all the kWh. A 10-year guarantee? Well, we can say this much, then: Tesla is extending its tradition of making products for the 1%. And they really should knock it off about positioning themselves as some sort of solution to energy generation, before we all burst out laughing.


I recall that the 2012 Tehachapi battery storage complex was over $1,500/kWh. It’s getting cheaper fast.


I rubbed elbows with Southern California Editor in a previous life. I cannoty imagine those people using company money for that project. This had to have been Uncle Sucker. Only the federal government would be quite that brain dead.

Ford Prefect

These battery packs sound like a great idea for a motor home or a camping trailer so you don’t need to run your generator at night (or until the permitted time).


A lot of people with RVs take extra 12-volt batteries for that job. No need to spend $3,000 — before the markup, which I’m sure will be hideous — for a Tesla battery. I think this new product is going to lay an egg. Too expensive. Way, way, waaaaaaaay too expensive.

Get Real

Well I see that the newest Tesla-Hater CP has magically appeared on this thread about Tesla’s newest product with no less then eight highly negative posts in about an hour.

Its funny but I don’t see CP on any other threads except ones that are about Tesla, makes me wonder if someone is paying CP and others to jump into Tesla news to spread their negativity?


If you only see me in threads about Tesla, all that means is that you read nothing but Tesla threads.

Get Real

No, I read and occasionally comment on Inside EVs which happens to include alot of Tesla stories probably because Tesla just happens to be leading the EV revolution if you will.
Nice try though!

BTW, I didn’t happen to see you comment on the Edmunds article, you know the one where Edmunds gives a very high rating to the Tesla Model S.

I guess you didn’t go there since it completely deflates your earlier assertions that Tesla sucks because Edmunds said so?

So I guess now Tesla has to suck because it comes from what you choose to call “SillyCon Valley”?


Do you work in Sillycon valley, then?


SillyCon Valley?

Really? Someone jelly.


@Get Real.
All what CP seems to say is that it is unclear what market those things are made for. Given little information Tesla disclosed regarding full cost of those products (retail price + installation cost + ancillaries such as inverter) I do not find this surprising. Is this opinion allowed here or should we revive the Spanish inquisition bonfires ??
A little less theatrics & hype, more hard facts (figures, graphs, like anyone else selling batteries out there) would easily fix this.


I compare this with the promise of the Bloombox a few years ago, where by now, they were supposed to have a home unit available for about the cost of an air conditioner unit that could power your home. Years later, like all fuel cell tech, it seems – and it’s still “a few years out”.

Cool thing about these batteries – is they will start shipping in summer! Wow!

Scott Franco, the greedy republican

Using sealed AGM batteries as a baseline:


6 volts, 415 amp/hours, 6*415/1000=2.49KWH, I am getting 7kwh is 2.8 times that, so I am getting an equivalent of:

7kwh: $1411

So Tesla is about double the cost of AGM batteries.

The battery/off grid solar market is pretty well established, with existing players. Whats the business model here? Selling the Tesla name????


AGM batteries have a lower tolerance for discharge than Litium-Ion. Best not to drop AGM (or any lead-acid battery) below 50% state of charge. So the Tesla battery might not be such a bad deal after all.


lead-acid batteries do not have a long cycle life. Especially if you deep discharge them. The Tesla Li-Ions will last at least twice as long as lead-acid so it is actually the Tesla battery that is the bargain.

I ran the numbers on this once when looking to replace the lead-acid batteries on an NEV with LiFePO4 batteries. The lead-acid batteries were cheaper in the short run but in the long run, the Li-Ions would be the better choice.

Jouni Valkonen

Actually, Tesla batteries will last probably four or five times as long as Lead acid batteries. The life time of Tesla power wall is around 10 to 15 years where as Lead acid batteries cannot last more than 2-4 years.

In addition, lead acid batteries has low efficiency, around 80 % and only about 50 % discharge depth is possible, where as lithium ion batteries can go up to 80 % discharge depth. Or more likely it is that actually 7 kWh version is software limited to 7 kWh to ensure optimal lifetime. Where as 10 kWh version has deeper discharge depth as it is for back-up solutions and not for daily cycling. That is, both 10 kWh and 7 kWh versions have same amount of battery cells, I would guess.

Therefore, I would guess that Tesla Power wall is cheaper than lead acid batteries by factor of six. And for commercial applications, by factor of 8.


Oh, I agree. I don’t know the actual end result (I don’t think anyone fully does because all these most recent battery chemistry mixes are new).

But we know that the Tesla Li-Ions will last AT LEAST twice as long as lead-acid.

I was kinda surprised when I ran the numbers. I figured that NEVs would then be using li-ions. But I guess companies just keep doing what they have been doing for years unless they are really forced to change. And switching to Li-ions does cost much more up front than lead-acid even though they are much cheaper in the long run. And that right there is the issue. People look at the up-front cost not the fully lifetime costs. That is why people by ICE cars and not EVs . . . and that is why NEVs use lead-acid not Li-Ions.


Pretty sad that an EV website can’t correctly use the terms POWER and ENERGY. I know that they are interchangeable in common vernacular, but that doesn’t mean that a EV oriented site should not use them correctly.



hello i search a new solution for energy hOUSE 12000 kWh YEARS

Ian Porter

I found the presentation poorly delivered by Musk, hyped-up by the stupid Apple-style ‘Wooing’ from the audience (was this the same rent-a-crowd?) and insufficiently detailed to be taken seriously by other than the brand name that everyone seems to stand to attention to because of the game-changing nature of the Tesla EV. I will wait for the facts. When the Chinese/Asians get a hold of this market, watch the price falls. So he has put a brand label onto a product with a following, the notion probably being to capture the attention of people who cannot afford a Tesla car that can give them entry to cred the label brings and of course to all the car owners who might just buy it because they have to have everything Tesla. So in 12 months lets see where things are at.


I could have wrote what you did.

So, +1


10kWh version only provides 2kW sustained.

A similar rated generator cost $599.

We haven’t even include the price of inverters and labor yet with the battery backup.


Is the similar generator automatic? Does it fill itself? Then you also have noise, vibratsion and fumes to deal with.

It looks like the backup model is geared towards longer, multi-hour breaks. Telecom, IT, Security equipment and emergency lighting. For those applications it is a great match.
For domestic use? Nope, unless we are talking about a cabin.


I also think is great for retail stores and offices.


Well . . . on the good side, an inverter can be quite cheap. It really depends on the size you need.

People can set things up in various ways depending on what they desire. For example, I might want to just add a really small back-up system that allows my solar PV system to run independent of the grid in an emergency situation and just supply my refrigerator, router, a computer, and a couple lights. In that case, a very small inverter would be fine. I don’t need my whole system in an emergency. Just keep my food cold, let me communicate with the world, and some LED light. Dishwashing, clothes washing, AC, etc. can be done by hand or wait until the grid returns.

Neil Dunn

This story has actually made the front page of The Times! (popular UK newspaper)http://www.bbc.co.uk/news/blogs-the-papers-32561630

mtr sun

Nothing New under the sun, I’ve used a simular solution for 13 years, the only new is the look and capacity!


mtr sun – I find the box spec of 2KW a little lacking. It seems like they want to sell you multiple boxes for aggregating power throughput to higher amounts of KW.

In california, they did pilot projects which are referred to as 5KW in power. Now, this new box has a continuous spec of 2KW. I don’t get it, really. Why not at least try to match the competition in terms of off-grid systems such as Outback or Schneider equipment. Even the SMA Solar TL array inverters which are relatively small offer a 15A 120V socket off the back for mid-day power from your solar if the grid is down.


They are not speaking about this in terms that are familiar to me as an off-grid home owner. I have a 24 volt battery bank with 1200 amp/hr reserve. They are not using terms like that to describe the battery. kWh is what I use over time but a battery pack is rated in amp/hrs at a voltage. Also, they say 350 – 450 volts. Off grid inverters usually work with 24 or 48 volt battery banks. I use a Xantrex XW (Schneider) inverter/charger.


Lee, would you be willing to answer a bunch of questions about solar panels, storage, and backup? I’m a complete numbers nerd, and have been toying with the idea of moving to a place where solar panels might make sense. Not moving for that reason, but if solar might work out then I’d consider it. Anyway, wanted to ask first before I go to work compiling questions. Probably about eight or 10 questions.