Tesla PowerWall

JoshK · May 2015

10kwh for $3500, and it hangs on the wall. Cool

They are solar ready, and up to 9 can be put in a home for a total of 90kwh. They begin shipping this summer.
I stayed up late and watched the announcement, thought I would share.

Steve L. · May 2015

JoshK wrote: »

I stayed up late and watched the announcement.

So did i...

I was in the process of pricing out lead acid and nickel iron battery banks for my new homegrown PV system, to see if I could afford to go off grid.

A lead acid bank for an off-grid system that will see me through 3 days of cloudy weather, would cost about $12-14k and lasts about 7-10 years.

A nickel iron bank of similar capacity is considerably more expensive, at about $25 to 30k, but may last well over 25 years and is supposedly much more forgiving, operation, maintenance and upkeep wise.

Both would require a dedicated room with racking for over a ton of batteries, proper ventilation to evacuate hydrogen and at my latitude, be insulated against the coldest part of the winter.

A similar sized Tesla Powerwall system would take 2, or maybe 3, of the Powerwall units at $7k (2 units) or 11k (3 units), is warrantied for 10 years, is maintenance free, weighs 440 or 660 lbs and installs on the wall of my garage, or basement!

I think Elon Musk just put a lot of deep cycle battery manufacturers out of business...

Brlux · May 2015

Help me wrap my head around this is it just a battery, looked like the voltage of the bank is 350-450V. Does it have it's own charger and inverter or is it meant to go between the grid tied panels and grid tied inverter supplying the inverter when the sun is not producing? Wonder what it's application is for off grid setups? Can you use it with existing solar equipment of all new custom stuff?

JoshK · May 2015

WOW - Ten year warranty with an optional ten year extension.

Technology Wall mounted, rechargeable lithium ion battery with liquid thermal control.
Models10 kWh $3,500For backup applications7 kWh $3,000For daily cycle applications
WarrantyTen year warranty with an optional ten year extension.
Efficiency92% round-trip DC efficiency
Power2.0 kW continuous, 3.3 kW peak
Voltage350  450 volts
Current5 amp nominal, 8.5 amp peak output

CompatibilitySingle phase and three phase utility grid compatible.
Operating Temperature-4°F to 110°F / -20°C to 43°C
EnclosureRated for indoor and outdoor installation.
InstallationRequires installation by a trained electrician. AC-DC inverter not included.
Weight220 lbs / 100 kg
Dimensions52.1" x 33.9" x 7.1"
130 cm x 86 cm x 18 cm
CertificationsUL listed

JoshK · May 2015

Briux, It has solar-input, not sure on output. It would work with any brand solar panel as I understand.

westbranch · May 2015

JoshK wrote: »

WOW - Ten year warranty with an optional ten year extension.

How many PV companies are still around, that were top of the pile 10 years ago?? Does the name Evergreen ring a bell? What is the likelihood of this warranty being any good? Just saying...

JoshK · May 2015

westbranch wrote: »

likelihood of this warranty being any good?

Well I don't buy anything I expect to need warranty on. I have been amazed for years with what a lithium ion battery is capable of for both work load and longevity. I have no reservations on quality or longevity. The wow for me is that they want to officially warranty it for 20 years.

JoshK · May 2015

I just reserved one

2Guido · May 2015

I am also trying to fully understand these specs. My current off grid system uses 24 volt inverters powered by banks of 6v AGM's and charged by solar and inverters chargers. Are these new batteries in anyway compatible to implement into my system??? Thanks !!!

froggersix · May 2015

.... too high voltage for anything invetrers or chargers so it will need all new equipment to work with. even i can understand that.

westbranch · May 2015

From my reading I would say that Off Gridders will not be able to use them as at that voltage one can only use it to back feed the grid...

JoshK · May 2015

Actually it's perfect. Nobody has enough wall space for 3 of those babies anywhere but in their garage. So the wire to the main panel will be long. This is what we call "unregulated" voltage in the DC world. Because what you get depends on the wire length and load. Then at the destination, there is small device that perfects it to the goal, 240VAC in this case. This is similar to an inverter, but because the voltage is only being decreased, the device is NOWHERE near the size of a inverter like is used with 12v batteries.

BB. · May 2015

With the right hardware, the high DC voltage is (possibly) becoming a standard for large data centers... You can ship 380 VDC into a 100-264 VAC input power factor corrected computer supply (as an example) and avoid the whole AC inverter thing.

And, of course, you can run AC inverters from that too--Just have to design them for off grid applications.

I believe, from what I have seen over the years, the automotive battery packs have chosen to go with lots of small cells in series to produce high voltage DC--Less copper for wiring and such.

I have always worried about the issue of lots of cells in series--I would think one really needs a per cell voltage monitoring system to ensure long battery life and avoid one of a hundred cells killing the entire battery string.

I have not looked at the Tesla announcements yet... I believe the "Dumb" comment earlier was directed towards designing an integrated high voltage battery bank that has virtually no support in the existing Off Grid / Hybrid inverter market (edited to avoid confusion).

While I can understand the questions about a completely different battery topology--It could become one of those game changing technologies. How this will all fall out in the future (good/bad idea)--I have no idea.

A good quote:

http://techcrunch.com/2008/04/29/its-easier-to-invent-the-future-than-to-predict-it/

"It's easier to invent th future than to predict it. --Alan Kay (misquote)

From a job listing by Jeff Bezos for Amazon in 1994.

Amazon has certainly shaken up the future--But what will fall out--Still to be determined.

-Bill

Brlux · May 2015

froggersix wrote: »

.... too high voltage for anything invetrers or chargers so it will need all new equipment to work with. even i can understand that.

I was asking if it had it's own power management to transform the battery voltage to a more standard In/Out for existing equipment. Say 48VDC or 120VAC.

It could potentially at those voltages be designed to go between the panels and grid tie inverter to bank some solar and then deliver it to the grid tie inverter after hours to keep supplementing house hold consumption and not have to rely as much on net metering. Though that would be an expensive option to net metering and grid down power is really the selling point of this to most people I would think.

Photowhit · May 2015

westbranch wrote: »

How many PV companies are still around, that were top of the pile 10 years ago?? Does the name Evergreen ring a bell? What is the likelihood of this warranty being any good? Just saying...

For the record, Evergreen is not the best example of this, Evergreen had some very good technology and though they went bankrupt they were bought in total before closing, by a China group. I don't know were this put warranty requests, but they have maintained the website ...

Photowhit · May 2015

From what I have gleaned, The battery is about 2/3rds the cost of the Winston/balqon offering and still greater than 2x the cost of my forklift battery. The warranty is very nice! But it looks like it will require different inverters and charge controllers to use in current off grid systems due to different battery voltages...

JoshK · May 2015

Brlux wrote: »

grid down power is really the selling point

I watched a video that one of the Tesla Home Battery testers made, power was out to all his neighbors, but his home was running.

JoshK · May 2015

Photowhit wrote: »

The warranty is very nice! But it looks like it will require different inverters and charge controllers to use in current off grid systems due to different battery voltages...

Yea unfortunately for anyone using vehicle batteries, this is different. But on the plus side, it's aimed at getting new people setup (that's me!), not re-configuring existing users.

DanKegel · May 2015

System cost is probably higher than $3500. With the matching inverter, maybe $7140, judging by http://www.bloomberg.com/news/articles/2015-05-01/solarcity-taking-orders-for-tesla-batteries-starting-at-5-000 and https://cleantechnica.com/2015/05/01/tesla-home-battery-price-competition/
Also, it's not clear how many kWh it can store daily; the "depth of discharge" might not be figured in.
Also not sure how much that degrades over time.

All that will probably be cleared up by this summer, I'm looking forward to hearing more.

Whether this pays off for anyone probably depends strongly on tariffs... for areas with no net metering, no FIT, and high demand charges, it'd potentially be a great deal, but the devil is in the details.

verdigo · May 2015

Forgive my lack of knowledge on these but why can't Tesla or the end user arrange the cell wiring to what ever voltage. Are the individual cell voltages out of the range of existing inverters?

solar_dave · May 2015

It isn't a big stretch to have an off grid inverter in those kinds of voltage ranges, I suspect the current line of inverters for grid tie could pretty easily be made to run from these batteries assuming you are still grid attached.

MarkC · May 2015

Interesting quote from one of the many recent articles:

"3. Notably, that doesn’t include the cost of the inverter or installation. In a conference call a year ago, Musk gave his first hint of what he wanted the Powerwall system to look like, including an "integrated bidirectional inverter, and it’s just plug and play.” The inverter and installation can more than double the price of a home storage system."

Appears these units are going to be designed to just "sit" between the grid and the user to supply battery based power - likely whenever you want it! If the utility companies would come up with a billing structure that would optimize their own generation capabilities and costs - and pass it along to the users - this concept could be a huge boon to us "renewable guys". Mass production of a very stable, warranteed battery design that appears to be almost cost competitive and maintenance free - too good to be true?? MPPT charge controllers of the correct voltage/control along with off-grid inverters might quickly follow. Also, for us Priups owners, this type of battery technology integrates well with our inverters already - just need to tone down the voltages a bit!

I doubt there will be much user configuration of these units - the battery management/charging/discharging schema I'd guess will be tightly controlled. But that has never stopped DYI'rs before. I wonder about heat dissipation??

Photowhit · May 2015

verdigo wrote: »

Forgive my lack of knowledge on these but why can't Tesla or the end user arrange the cell wiring to what ever voltage. Are the individual cell voltages out of the range of existing inverters?

I think they are shooting for a modular design, I'm sure cracking the case can and will be done, but a 10 year warranty might be a terrible thing to waste.

inetdog · May 2015

Photowhit wrote: »

I think they are shooting for a modular design, I'm sure cracking the case can and will be done, but a 10 year warranty might be a terrible thing to waste.

It is my understanding that the Tesla vehicle battery is highly modular, but the individual modules are all high voltage modules which are then wired in parallel.

Going to high pack voltage lets you minimize the size of intercell connectors and other wiring.

westbranch · May 2015

there is a further part to this distributed generation concept and that is to consider each house as a 'cell' in an even bigger storage battery and control the feed into the grid remotely... making the "Musk (Tesla?) Utility" a new competitor... look in the second video in the CBC News Article.....

solorone · May 2015

I would not bet against Musk, he maybe Tesla reincarnate. I have been reading about this for a year or so without learning much of the specs of the battery or even how they function, I assume, being used in the cars, they can deep discharge everyday. I am sure the voltage issue will work out, if nothing else I wonder what the loss would be of using a transformer to 220V ? I don't see 2 KW continuous as workable, at least not for my setup, it will depend on how long it can hold the surge. I think a 15 KW unit would be better, but it would take 2, 10 KW units for me, as we use about 8 KW a day. My batteries cost 7K and I expect, based on prior experience, 13 years use from them. I have been around long enough to see some awesome advances in solar, ( still waiting for the ever coming 35% efficiency panel :<)) ,,) so it will be cool to see how this all plays out. I need to know/understand how these batteries function, how fast they charge and how they hold their voltage as the battery discharges. Knowing more would surely shape my above uneducated comments. I wonder if you will need a fire proof battery housing ????????

pleppik · May 2015

verdigo wrote: »

Forgive my lack of knowledge on these but why can't Tesla or the end user arrange the cell wiring to what ever voltage. Are the individual cell voltages out of the range of existing inverters?

I think the key point is that Tesla isn't selling a battery, it's selling a battery system.

So the package includes software, charge management, monitoring, etc., and you can't rewire or rearrange the components.

This is likely to take some getting used to for people who have invested a lot of time an energy learning how to manage a traditional battery bank.

One interesting bit of speculation I've seen is that the 10 kWh and the 7 kWh units actually have the same physical battery inside the box--just that one is programmed for optimal performance with 10 kWh discharge on a weekly basis, and other other is programmed for 7 kWh on a daily basis.

westbranch · May 2015

pleppik wrote: »

One interesting bit of speculation I've seen is that the 10 kWh and the 7 kWh units actually have the same physical battery inside the box--just that one is programmed for optimal performance with 10 kWh discharge on a weekly basis, and other other is programmed for 7 kWh on a daily basis.

Do you have a reference for those numbers? I have a bit of a reaction to why someone would pay $3500 for 10kWh /7 days vs $3000 for 7kWh every day?

Photowhit · May 2015

He does say speculation, but I was curious my self, if it is indeed the same or very similar chemistries, I suspect they are shooting to stay within the 20-80% sweet spot with the 7KW rating.

pleppik · May 2015

westbranch wrote: »

Do you have a reference for those numbers? I have a bit of a reaction to why someone would pay $3500 for 10kWh /7 days vs $3000 for 7kWh every day?

Right off the Tesla Energy website: http://www.teslamotors.com/powerwall

They list two models, "10 kWh for backup applications" and "7 kWh for daily cycle applications."

Tesla has a ten-year warranty for both models, but over ten years the "daily cycle" battery would have around 3,500 cycle, and the "backup" battery would have many fewer cycles, probably less than 500.

So the speculation is that both models have exactly the same battery pack inside, but the "daily cycle" version is programmed to provide less discharge in order to preserve the 7 kWh of available power through 3,500 cycles, while the "backup" version is programmed to allow you to pull up to 10 kWh in a cycle since it only has to last a few hundred cycles.

This also presumes that the integrated charge controller is designed to make it hard for the customer to damage the battery by discharging it too deeply (hard, but not impossible. Just like a Tesla car battery, you could wreck this battery by discharging it and then disconnecting it from the power for an extended period of time).

Imurphy · May 2015

I have been following the system install and design of this guy over on the tesla forum. He has hacked several of the 80kw Model S battery packs as the base of his system. Yesterday he posted in interesting opinion on the tesla powerwall. I think he is on track. It would take 2 of these to replace the bank in my motorhome and about 12 to replace the bank in my house. Thats alot of coin....

http://www.teslamotorsclub.com/showthread.php/46756-Elon-I-love-you-but-the-PowerWall-isn-t-that-great-yet?p=994934#post994934

Tesla PowerWall

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