Let’s Get Straight: Tesla Powerwall DOES = $3,000
As you all know, I’ve been having a lot of fun working with a few readers to dig into the price of Tesla’s Powerwall a bit, and how it compares to competing products. However, something we’ve been assuming, and that I’ve seen all over the interwebs, is apparently wrong. The assumption has been that the $3,000 price for a Powerwall is the wholesale price.
I reached out to Treehouse this week, one of the initially listed Powerwall partners, to find out what kind of markup it would be putting on the Powerwall. I was informed that the Powerwall will actually retail at $3,000 on the site. Wow.
Of course, as stated previously by Tesla, most of us need an installer to hook up the Powerwall if we want to use it, and SolarCity is giving an initial estimate of $7,140 for the whole shebang, or $5,000 for a 9-year lease. But if you are a true DIYer or off-gridder, I think you must be happy to hear this news.
Also, perhaps SolarCity’s prices are a bit high (it does anticipate the price coming down in the coming few years) and perhaps other installation partners will offer a better deal.
Anyhow, next time someone argues that $3,000 is the wholesale price for the Powerwall, you can send them our way.
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Wow indeed! That’s a great price.
Are any other companies offering that price?
As it’s going to get cheaper in the future… Double Wow!
Hopefully it does get cheaper due to the Gigafactory, but who knows.
Maybe Tesla will sell these at a loss now until the factory is up and running.
The news just keeps getting better, doesn’t it? And yes I do suspect that Solar City’s fully installed price is higher than necessary for a frugal installer. Didn’t Tesla say ” two people, one hour”?. It takes two because the battery weighs 220 lbs. So one strong guy and an apprentice electrician.
The final pieces in the puzzle to be nailed down once and for all are: can you hook into any pre installed inverter? And, does 7 kwh model mean full discharge of 7kwh per cycle?
“can you hook into any pre installed inverter?”
I suspect you can if your own battery energy is being pushed back towards the grid (as AC) from the 7kWh unit in TimeOfDay load shifting mode. The PowerWall unit will just look like another 400V solar module string – even at night.
In backup mode (using the 10kWh unit), assuming the grid is down an existing inverter will refuse to run due to its built-in anti-islanding feature. And anyway it would be trying to feed the whole house +grid. The intent, according to the SolarCity web site is to supply limited function 2kW critical circuits, only when the grid is down.
This would require a dedicated inverter and would involve some other power switching shenanigans to supply the critical 2kW when the grid is up but the sun and battery are down.
I believe there are specialized inverters coming on the scene – SunnyIsland rings a bell – which may help here. But it’s an additional expense.
What’s needed most of all is a full technical description and specs.
Without that it’s all a bit like sprinkling fairy dust.
SMA has a grid transfer switch. There are others. SolarEdge and other brands do automatic shutdown when grid fails.
The Solar City installation includes an inverter and the PowerWall. I am not sure which PowerWall goes in that offer. If its the 10k, $3500 one or the other one. The SolarEdge SE5000 inverter is 5k and costs about $1330. So there is a significant mark up on the complete system. There are a few other items like a grid switch for automatic grid disconnect possibly, but not a whole lot more.
Installation requires significant labor and parts, especially for the backup system (the only version SolarCity will offer initially). The house wiring will need to be split between two breaker panels / load centers.
There is also no guarantee that SolarEdge (or anyone else) will produce off-grid/dual-use inverters for as little as their current grid-tried versions.
Yes. One of the things that comes out of analyzing these options is the realization of what works and what is economical.
Emergency backup is not just a matter of buying a generator and turning the crank to start it up.
You need a really big gas generator to power air conditioning loads, for example.
http://www.electricgeneratorsdirect.com/stories/36-How-to-Pick-the-Perfect-Home-Standby-Generator.html
Even gas generator sales start steering you towards separate loads and breakers.
Can you explain what you mean by dual use inverters?
Why the need for a dual use inverter. Just put you grid tied inverter behind the big battery pack and off you go.
LOL, “two people, one hour”…
To attach the battery and inverter to the wall, sure. Redoing the main breaker panel and installing a secondary one, necessary to isolate whatever circuits the homeowner might want powered by the backup battery (the only configuration that SolarCity will offer initially), and all the conduits and wiring between each piece, will take dramatically longer.
I went through a main breaker panel upgrade a few years ago, it took the whole day (and a 4-figure bill).
Yes. Breaker panel installation is best left to an electrician. I wonder why one couldn’t power the whole house on backup? I guess they figure that if the grid fails suddenly and your air-conditioning is on, its too much load for the battery backup. It sure is a hassle to make a separate breaker box and rewire just critical loads to it.
Why should it cost that much to install? If you already have solar, I thought it was mostly just a matter of slicing it in on the DC side of your existing inverter. Seems like a couple hours work and minimal parts beyond the Powerwall itself.
Most modern residential PV solar systems use micro inverters attached to the back of each panel so it’s not as straight forward for all solar systems. There may be an opportunity to do what you’re mentioning (that was my original understanding of one option for system design) but many will require another inverter to convert AC to DC (to charge powerwall) and back again (to use power from the battery).
If you have micro inverters, the system is complete and storage is difficult to slip into the system. Microinverters are made for direct solar to AC.
Other systems have MPPT and a large inverter in the house. If the inverter is 400VDC in, the PowerWall slips in between the solar PV and the inverter seamlessly.
Any work like this should have an inspection for safety and because it will add to the value of the property and lower insurance costs.
Unfortunately, again, you can’t simply add this battery to the DC input of a regular inverter (before the MPPT) and expect the PV to still work properly.
The only systems I can foresee this may work with (assuming that the pack includes a 350V DC-DC) are optimizers-based, where the battery can be inserted between the MPPT and the inverter.
This still only covers the PV time-shifting case. For backup (or to time-shift off-peak grid power), a new or different inverter will need to be installed.
Thats right. If the MPPT is inside the inverter, thats not going to give the solar any MPPT with the battery in between.
SolarCity need humunga dunga mark ups to pay the large salaries of their executives and recover some of their operating expenses. marketing and building your distributorship isn’t cheap.
Citation?
/hungadunga/usaidit/yeow/
Or do I have that mixed up with a different one?
SolarCity only plans on selling the backup version. To power some loads while the grid is down, a new inverter is needed, as existing grid-tied ones are designed to shut down if the grid disappears (and can’t charge a battery anyway).
Also, the house existing breaker panel has to be pretty much split in two, with some automatic switch in between (which may be part of that new inverter).
Anyway, a significant amount of hardware and labor will be necessary. 3.6k$ seems quite cheap for this actually, and probably assumes a straightforward install and an existing leased PV system, from which they can pull an inverter usable for another customer.
A few days ago, I got an off the cuff quote of $2500 just for the necessary inverter to make the powerwall work with my existing grid tied system as a backup.
So where do I place my order?
Hey unless you have experience with electricity don’t do this yourself. The pack has a 5.8 amp current. To put that in prospective 1amp WILL kill you if you make a mistake. Hell half an amp can kill you. Your house line has even more current. Don’t mess with electricity.
People can “mess with” electricity rather safely and do so on a regular basis without many incidents. It’s when people don’t read the instructions or don’t know what they’re doing that accidents happen. If Tesla designs this thing correctly, then a lot of people across the country could be able to install the Powerwall no problem.
One can install as in place the battery’s on a wall with the correct inverters and control equipment and do the same with pv on the roof but and this is the important part then get a qualified technician to come and do an audit and he/she does the connections and earth leakage tests.
The paper work has to be submitted by the company that audits your install.
Frankly get the advice before doing anything reputable companies will assist with this service.
Take a look at some of the DIY battery pack websites. Ever see a hole the size of a dime blasted out of a wrench faster than you can blink? Thats what a 400VDC 5A battery pack can do.
If the pack maxes out at 5A, that wrench won’t even heat up in a way you can feel it (remember, P = I^2 ⋅ R).
400V can easily kill though, so that’d be the main danger here.
To melt stuff, the dramatically higher current that e.g. big but lower-voltage lead-acid crank batteries can (briefly) produce when shorted would be much more “adequate”.
Now the Tesla Pack doesn’t have much C. Remember, it can go to 8.6A in peaks. But thats rated, not what it will actually do if you short it. Of course, an ordinary LiFePo is a little worse, and A123 with 25C? You are lucky you have a hand left. I wouldn’t try an experiment to see if LiFePo or PowerWall wins.
Personally, I have seen a pair of needle nose have a smaller hole dredge out of it from only a few cells shorted, not the pack. I shudder to think what the pack could do. And if the pack starts heating up, better run for cover. Seriously. No joke.
And no, this is not theory. It doesn’t just sit there and glow.
http://www.solarjourneyusa.com/Pictures/wrenchsc.jpg
http://www.solarjourneyusa.com/learn-build-array.php
Electric i found easier than plumbing. If done properly little to no danger at all.
residual current switches trip at 30mA to protect you (for 230Vac/50Hz that is)..
I think that is just Amps, not milliamps.
For safety, ground fault currents are much less than Amps. Its milliamps.
No, definitely mA not amps as an earth leakage current i.e. difference in current through the active wire as compared to the neutral. Some will trip as low as 10mA for medical applications.
as the others already said, it’s indeed just 30 mA at 60+ Volts that can cause your heart to lose it’s rhythmic beat..
Ref.: http://en.wikipedia.org/wiki/Residual-current_device
So be careful out there folks!
And if you can afford it, get RCDs installed into all your circuits.. these days they are available 1 unit wide (same as MCBs) and cost ~40 AUD up here in the woods where I live. http://www.sparkydirect.com.au/assets/thumbL/ADC320T.jpg
Milliamps can kill you when the voltage gets high enough. Ground fault circuits have to trip when they measure currents under 100ma.
DC is particularly bad. If contact is made, unlike AC which passes through zero current on each cycle, current and voltage are constant. If an arc is drawn, it tends to stay.
There is a protocol. You are supposed to wear special heavy rubber gloves that are high voltage rated. You have a protocol to blow them up before each use to make sure there are no punctures. Thats a bare minimum. All ties, rings, and jewelry must be removed. See what I mean? Not for the faint hearted. You must have some experience.
I would say register now the supply has been used up to the middle of 2016 with orders already.
Once the Giga factory comes on stream the supply will even out in the first week it seems some 37000 orders have been taken.
The best way I feel to use the Powerwall is hook up 2 of them in the 7kwh configuration with PV so that it is usable for peak demand not in the high discharge mode as that will only allow a limited number of discharges per year.
thanks.
The big red button here to reserve is your best bet. They let you pick the time frame on which you want your powerwall: http://www.teslamotors.com/powerwall
thanks for the link. will try it later.
The solar city installed price is higher than what they quoted for a Tesla system last year….hmm. I think it was $1500 down and $15/mo for 10 years though I don’t recall what size that system was.
The lease might be a good deal for a change. After 9 years, the battery will have cycled about 3200 times and its resale value might not be that great. For starters, you would need to pay for Solar City or another buyer to come back and haul it off. If the install costs $4140, then tearing it down might cost half as much or so (just a WAG). Secondly, a 9-year-old battery would be woefully obsolete by that time, so even if it retained a lot more capacity than predicted like Roadster batteries are doing right now, the resale market would be a tough road for a used Powerwall. Finally, the opportunity cost of $2,140 over 9 years comes to almost $3,000.
If the lease includes installation and decommissioning, then it’s a good idea. Plus, who knows if putting in a Powerwall will add you your property taxes. A lot of counties exempt solar arrays from increasing property taxes, but they may not be as responsive to technoogy like the Powerwall for some time. A lease mostly protects the property owner from this uncertainty.
Now if the Powerwall lasts significantly longer than 9 years, then buying might be a better idea, but it’ll be a long time before hard data is available to prove this is true.
One of the rumors that I have seen on the interwebs is that the big difference in price between the lease cost and straight out sale price is because of a core charge on the unit in order to make sure of return for recycling.
Now with what has been said about the Gigafactory with a section dedicated to servicing and recycling the the automotive packs this makes sense for the home units also.
But I have found no way to verify this one way or the other.
What is the life of the battery, much more than nine years?
The battery is warrantied for 10 years, but in the conference call Musk stated 15 year life was expected.
So how does the lease benefit the installer? What are they going to do with a battery that has 1 year warranty left (if it transfers) and 6 years of life (that could be exaggerated because it is an unverifiable claim at this point). How does getting the battery back justify the less money they get for the install?
Future sales. As battery tech grows. Replacement installs and capacity expansions make money. Also services.
Actually, any long term claim is unknown in the application. Li batteries are relatively new. But if the warranty is 10 years, the service life has to be more or there is too much warranty cost. It is reasonable to assume some life after warranty. Otherwise, cars would die at 60k miles.
True, Tesla must have had some way of accurately estimating their life before offering a warranty.
But I think they should get future sales, capacity expansions and services from a sale as well. Although a lease probably locks them in for service and expansion of the leased product.
My concern is that it seems wasteful it the leasor takes the 9 year old batteries and recycles them versus the buyers using them for their entire life.
The other thing is that everyone expects the batteries to get cheaper over time.
It may be $3K but you still need to buy some isolation circuitry, an inverter, and a charge controller.
You don’t need a charge controller or isolation. The charge controller and DC-DC are built into the PowerWall. (also BMS) If you have a SolarEdge, Fronius inverter, or other compatible, 400VDC input inverter, the installation should be simple. The SolarEdge shuts off if the grid power fails.
The PowerWall just connects from the PV solar and outputs to the DC to AC inverter. Thats it.
Its only if you want to have emergency backup power or automatic grid disconnect that it becomes more complicated.
And if you have a low voltage inverter, you can’t directly connect it to the high voltage output of the PowerWall.
I already have a functional micro inverter system that I plan to grow over time … so I wonder how adding a Powerwall will work, whether additional batteries will be easy to add over time, what other components will be needed, the out-of-pocket cost for a basic one battery installation, and whether the cost will qualify for any tax breaks. Supposedly, this integration will require a separate Powerwall inverter/charger, plus some sort of load detecting/switching system that determines if AC (from the solar inverters) is more than the house requires, then routes solar excess to battery charging – or determines whether solar output is insufficient, then routes only the degree of AC (inverted battery power) needed by the house so that grid AC is not needed? Very few details seem available so far.
I hope that Enphase Energy builds an ‘AC Battery’ front-end to connect the Tesla Powerwall to a microinverter based home. It would also work in homes without any solar PV.
Not sure about your application. Microinverter usually means something like EnPhase where there is an inverter on every solar module. That puts out AC directly. Then all the AC outputs are combines in parallel to the house. There is no way to get inside that and put a battery there before the inverter.
The idea behind PowerWall with solar is simple. A typical PV solar installation without batteries takes the 400VDC output of the solar PV modules and ties it into the DC to AC inverter. PowerWall just gets inserted between the solar PV and inverter.
Its just an add in.
Solar Edge is a Tesla/SolarCIty partner. Their inverter takes 400VDC in and outputs AC. it automatically shuts down if the gird loses power for safety.
Thats all. Nothing else to do or change.
The solar PV charges the battery. Nothing else has to.
If you want emergency backup, a grid transfer switch is necessary. This shuts of the grid power so the battery can power the inverter to power the house.
A further complication ensues if you want automatic grid disconnect. Then the grid transfer switch has to be smarter, to disconnect automatically, not manually, when the grid fails.
I just scanned Enphase. They are planning to mount individual batteries near each of their roof mounted micro inverters. Hate to say it, but I don’t like that idea much. Hard to lower costs that way. Also a bad location for a battery where it can get hot and harder to service.
It would be great if Tesla put out information about full configurations such as what is required for 1 to 9 units and using either one and what it does for you. I am a fan but this does seem lame for such ‘smart’ guys not to be more informative and does give the impression solar city is charging a bit much m I new. Especially at that price ‘per battery’ even in a multi battery configuration.
Yes, the information on their page I am sure was professionally executed. But between the web designers, graphic artists, and engineers, something fell through the cracks. They need to sit down with a little group of off grid people and find out what they want to know. Then with solar grid connected, then with Rv, then with yachters. Tesla got advice from solar city, but it is amateurs who are needing information in capital letters with drawings and no techno jargon.
Vensonata – Yes – I don’t think they had off grid people or DIY in mind at all, and it shows. They make it clear that distributors are a big part of their model. Off grid has not had much full turnkey service until lately. There always seems to be some odds and ends that the user has to figure out.
Sounds like Tesla had people that have no idea about electricity in mind for residential, and big utilities and businesses with professional installation on the other hand.
Isn’t the $3,000 Powerwall only 2 Amp service, and most ‘middle class’ homes will need a few more amperes … dadsolar .com
2kW not 2 amp; Still not enough to power most homes but they can be stacked to 18kW.
If you tried to use 10 kW from your residence, the utility would stop you. They don’t want to allow EV chargers without approval, because they cheapened up distribution by only providing the least amount necessary to meet everyday demands. Distribution is not strong enough now to power every house at main breaker box 100A ratings. Nobody really gets 10k per household for every household.
Even old 60A service could provide 10 kW without a sweat, and I see no reason why a utility would mind that kind of load.
Heck, running my dryer and cooktop simultaneously would easily go over that already…
Obviously not everyone could simultaneously suck the maximum that their service is rated for, but why would such situation ever appear?
I certainly didn’t have to get approval from my utility to charge my EV either.
Some ask that people tell them, so they can see if and where “plug-ins clusters” form, and anticipate higher night-time loads in such neighborhoods. The lines are fine, but some older (now undersized) transformers may rely on the lower night-time use to cool down.
You tell me.
“Individuals and entities installing EV charging stations on their property are required by the Illinois Commerce Commission to notify their electric utility both before and after their EV charging station installation, in accordance with the ICC’s “Certification for the Installation, Maintenance or Repair of Electric Vehicle Charging Stations” (83 Ill. Adm. Code. Ch 1. Subch c. Part 469).”
http://www.illinois.gov/dceo/whyillinois/keyindustries/energy/pages/ev.aspx
An electric dryer is rated at 5kw and an EV charger is 3.3kw or 6.6kw. Yet you don’t see utilities restricting them. Or baseboard electric, or hot tubs, or….
5A continous, about 8A peak.
Yes… 5.8A BATTERY current (350vdc); 5.8A x 350vdc = 2kW. NOT 5.8A at residential voltage. This would supply continuous house current @ 240vac of ~8 amps. POWER = CURRENT x VOLTAGE.
Hmmm. Yes. Thats the correct current at 350VDC, and the PowerWall voltage is 350-450V according to the source.
Considering household voltage of 120V, that works out to 16.66A continuous, 27.5A peak.
http://www.teslamotors.com/powerwall
From 120V, the current is 16.66A.
Are you aware that the battery that one of the most popular names in the Lithium Ion battery storage industry is offering, can only output up to 2,000 watts of continuous power? That’s not much more than a single hair dryer set on high.
What good is having a residential solar storage system if your continuous power output is limited by your lithium battery’s chemistry ?
A far better alternative would be to connect your home to a lower cost bifacial solar powered LiFePO4 (Lithium Iron Phosphate) battery storage system.
LiFePO storage batteries offers longer lifetimes, better power density (the rate that energy can be drawn from them) and are inherently safer.
Are you trying for more FUD, so another article like this has to be made? Just exactly how does that limit a grid tied application? Suppose you have solar and are grid tied. Now you add battery pack. You don’t need peak power. You already have it. It matters some for off grid. But off girders are more efficient with their uses and don’t use high current loads as much. BIggest one is refrigeration. Off grid might be better served by more than one PowerWall anyway. You can power with LiFePo, but its more expensive. Believe it or not, the C rate on a Balqon ESS is only 0.5C, only a little more than the 0.35C on the daily use PowerWall.
You can get much higher C from A123, ridiculously high, in fact, about 25C.
But here is the deal. Battery chemistry trades off high energy density for high power density. A123 can do somewhat better than most because of their nano formula.
But why buy it if you don’t need it?
So now it is two weeks since the battery announcement and we seem to be clearing up some considerable confusion. I have an idea. Tesla needs to hand out a few samples to a couple of dozen select clients. A few off grid, a few solar grid connected, a few rv’s and yachts etc. then they need to make little youtube clips of the installation, results, and customer satisfaction. All this confusion can be cleared up. Anybody want to write to Teslas PR department? They haven’t needed to advertise their cars, perhaps they did not realize how different a battery is than a car.
I’ll drink to that.
Just written too them 🙂
Do you honestly believe that Tesla is going to sell you a 350+ DC battery pack to you for a DIY installation ? Are you joking ? 350+ volts is about as lethal as it gets. I challenge any of you to try and order one these these batteries for a DIY installation. Be sure to post pictures once your shipment arrives. LOL !