
Powerwall 2 and Integrated Solar - ph0rque
https://powerwall.tesla.com/?powerwall2
======
Loic
Quick question for the people living in the US (Target customers of the
Powerwall). What is your yearly power usage?

On the website[0] they put for sizing 10kWh/day/BR. Which means 14600kWh/year
for a 4 bedroom house. Here in Germany, working from home with a 4BR+office
house, we are using 2550kWh/year. So, I suppose the Tesla sizing is to support
a "peak day" usage, but still, I am surprised by the calculations. This is why
this totally informal and unscientific survey :)

[0]: [https://www.tesla.com/powerwall](https://www.tesla.com/powerwall)

~~~
antisthenes
The reason their calculations are so high is because in the US, typical houses
are made as cheaply as possible, pretty much with paper, plastic and vastly
insufficient insulation.

That may have changed in the recent years, but holds true for most residential
properties built before 1980.

~~~
ghaff
What a sweeping generalization.

Furthermore, unless you're in an area of the country that requires the use of
a lot of AC--or you have electric baseboard heat--insulation doesn't even play
that much into electricity usage.

~~~
binoct
I can see why one would bristle at the term 'cheap', but where energy
efficiency is concerned there is a big difference between the EU and US.
Energy costs are higher, regulations tend to be stricter, and usage lower in
the EU.

On insulation, I'm assuming you mean in areas where AC isn't heavily used
insulation doesn't help electricity bills if heat is provided by gas/oil?

~~~
ghaff
>On insulation, I'm assuming you mean in areas where AC isn't heavily used
insulation doesn't help electricity bills if heat is provided by gas/oil?

Correct. Heavy use of electric heat is fairly uncommon as it's relatively
expensive. (In the Northeast, it would be considered a serious negative if a
house had only electric heat.) Of course, insulation helps with overall energy
usage if there's either a lot of heating, a lot of cooling, or both--however
it's provided. I'm also sure the US tends to have larger houses, more large
electric appliances, and other home features that increase electricity use.

------
DvdGiessen
For those who are looking for something similar but (being the kind of people
who read HN) would like something more configurable and hackable, you might
check out the products of Victron Energy[0]. They've also have an optional
remote management portal[1] which allows you to set up and monitor everything
remotely for years now, and most the software running locally on the devices
is open source and fully modifiable (such setups are even supported!).

Full disclosure: I'm one of the developers of the mentioned Remote Management
portal.

[0]: [https://www.victronenergy.com/](https://www.victronenergy.com/) [1]:
[https://vrm.victronenergy.com/](https://vrm.victronenergy.com/)

------
swampthinker
Solar panel roofing tiles have been around for a long time. I wonder what this
will do different? Pricing? Or perhaps they are relying on brand strength
alone.

Edit: I understand the urge to downvote because I'm not singing praise, but I
promise I'm not trying to be overly pessimistic or critical of what Tesla is
doing. Fact of the matter is, solar tiles have been done before, and failed
miserably.

~~~
makomk
Marketing and business model, primarily. Previous solar tiles were more
expensive than conventional solar and so are these. The difference here is
that Tesla and SolarCity are marketing it as no more expensive upfront than a
conventional roof replacement by keeping ownership of the roof and having
buyers sign a contract committing them to buying power from it at ever-
increasing prices.

There also seems to be some efficiency and aesthetic improvements over
previous tiles, but those alone wouldn't be enough to make it viable.

~~~
Brakenshire
> Marketing and business model, primarily.

And from that, hopefully, scale. Solar tiles have always seemed to be a very
poor relation of solar panels. The approximately 1x1.5m panel is a sort of
informal global standard, and that's meant that solar tiles have been much
more fragmented, much lower scale, and much more expensive.

On the other hand in theory these solar integrated building materials should
greatly reduce the associated costs of installing panels - labour is usually
something like half the cost of installing rooftop solar, but if you can
install a solar roof without much more effort than a normal roof, those extra
labour costs are massively reduced.

If you can leverage this labour cost advantage to ramp up scale of the tiles,
and get them close to the per watt cost of traditional panels, this is how you
can really make rooftop solar competitive. These labour costs are why rooftop
solar is so much more expensive than utility solar. If you can greatly reduce
them, total costs are much more tied to the cost of the tiles themselves, the
inverter, and so on, where there is enormous leeway for ongoing reductions.
Very exciting.

------
andrewtbham
the cool thing is that they look good... they look like a normal roof at the
angle you would see from the street in front of the house, but from above...
from the angle of the sun they are transparent and you can see the solar
cells.

I know some rich people that want solar but their neighborhood associations
won't allow it, but I don't think they would not have an objection to these
roofs. they look really nice....

I have been curious how they were going to compete with cheap chinese solar.
this seems like a good strategy but one that may be easily copied.

~~~
option
In CA, it is illegal for HOA to block solar installations

~~~
iamcreasy
What is HOA?

~~~
smokeyj
Just google it. I'm getting tired of seeing so many low effort comments. I
used to come here to be informed..

~~~
quickben
Just imagine if they wrote encyclopedias in your communication style.
Completely fictional example:

From Ye Great Book of All Scottish things, 856 year of the Lord, page 17: \-
yepswatter : a very commonly used household object, just ask anybody around to
show you one.

------
Animats
The thing is cloud-connected, remote-controlled by Tesla. That presents a
problem. Will the cloud service behind it last the life of the system? Most
cloud services evaporate within five years.

~~~
rsync
"The thing is cloud-connected, remote-controlled by Tesla. "

If your use-case is backup power in case of utility failure, how does that
work ? If utilities fail, the network connection to the battery may also fail,
right ?

~~~
beambot
It's not hard to imagine the solution: fall back to sane defaults like every
other system not connected to the cloud.

~~~
rsync
"It's not hard to imagine the solution: fall back to sane defaults like every
other system not connected to the cloud."

Almost nothing behaves like this - even if it claims to.

A good example is the sonos music system. They _claim_ that it will work
properly (with your local music source) without Internet access. That is
false.

~~~
greglindahl
One example is Tesla cars. They work fine when not connected to the cloud,
although you'll want to occasionally connect to install new firmware.

This whole thread is based on speculation -- the details are not yet known.

------
Tinyyy
[https://www.tesla.com/solar](https://www.tesla.com/solar)

For people like me who missed the solar roof.

~~~
whage
Thanks! Can someone tell me what kind of architectural style does that house
on the landing page represent?

~~~
zo1
You got 4 different answers. Something just isn't right with that:

    
    
        Modernist
        Deconstructionist Modern Style
        Muskhaus
        Contemporary

~~~
drakonandor
Pretty sure the Muskhaus answer was a joke, as Tesla is run by Elon __Musk __.

------
amluto
I have no particular desire to sign up just to watch the video, but I hope
that the Powerwall 2 is compelling enough to beat out the LG Chem RESU.

For reference, the RESU is a wall-mounted Li-ion battery meant to be connected
to a solar inverter. It seems to beat the Powerwall in basically every
respect. It's a bit cheaper, it has a better warranty, and it has slightly
lower advertised capacity but higher warranted capacity under basically all
advertised conditions. But it's not cool and doesn't have a shiny video.

~~~
annerajb
Tesla version integrates the inverter and has double the capacity(14kwh) for
the same cost as LG Chem REsu 9kwh version

One 14 kWh Powerwall battery $5,500 Installation and supporting hardware
starts at $1,000

~~~
mateus1
14/9 is not double.

~~~
BrittTheIsh
The powerwall went from 7 to 14. Double.

~~~
mateus1
Doh! I stand corrected.

------
manav
I haven't looked into it yet, but I'm curious about using utilizing my Teslas
in case of emergency for power. With 75kwh+ each (leased so no concern about
cycles) I don't think I'd need a powerwall at home.

~~~
sfblah
Can you explain to me your economic thinking behind leasing two Teslas? Are
you super rich or do you have some other thinking that went into that
decision?

~~~
deagle50
It's actually not a bad financial decision at all relative to other cars.
Reasonably specced Model S montly lease costs after tax benefits come out to
well under $1000/month. That's on par with a mid-high spec E-class or
5-series. Now factor in fuel savings and small business lease write off. Plus
access to carpool lanes during peak hours and prime parkin spots.

------
intrasight
For $3000 this would be easy to justify just to keep my computer and network
operating. I work at home and our power goes out too frequently. Is usually
just for 10-20 seconds and my UPS takes care of that. But sometimes it is out
for several hours - I'll say several times per year. If I can't work, I can't
bill.

~~~
TheSpiceIsLife
Where are you seeing $3000? When I set it to 1 Powerwall it tells me:

 _One 14 kWh Powerwall battery $5,500 Installation and supporting hardware
starts at $1,000 Total estimate $6,500 Requires $500 deposit for each
Powerwall_

~~~
JoeAltmaier
Hm for that price I can install a natural-gas generator. Have power for days
if necessary, full power on all circuits.

~~~
TheSpiceIsLife
Which still ties you to the 'grid' insofar as you need the natgas supply
chain, even if you have a huge reservoir you'll eventually run out. Having
said that, batteries and solar panels don't have an unlimited life span
either.

I'm looking at buying a petrol powered generator for reasons other than home
power generation, but it will be reassuring to know we have backup power at
home, but I don't think I'm allowed to store any more than 25L in one
container on my suburban property. I guess that would be 25L plus each of our
two cars with full tanks.

It would be fairly trivial to convert a petrol powered generator to run on
propane from the barbecue gas cylinder, I've had experience installing gas
kits on carburettor engines in cars.

~~~
JoeAltmaier
Good points. But for me, I live on 80 acres and it happens that the county
natural gas pipeline runs under it. The easement (signed in the 60's) included
the right to connect to the pipeline at will. When we built the house, we
exercised that right.

So even though I am rural, I don't have to buy liquid propane to heat my
house. I'm tapped into a 100,000 home supply line. Its been depressurized
maybe twice for maintenance in 50 years.

Not a solution for everybody. But a pretty good one for me! And everybody else
on the line.

~~~
mikeash
Nice setup! How much did connecting to the pipeline cost? Making an individual
connection to something so large sounds expensive, but obviously I have no
actual clue.

~~~
JoeAltmaier
Fortunately there was a hairpin(?) connection across the road, so I agreed to
connect there. That means they didn't have to depressurize just for me. Cost
nothing (easement terms). However they charged me for the pipe to run the 200'
from there to the house! I could have negotiated that better.

------
AndrewKemendo
I signed up for the original powerwall and as it turns out it's not Tesla -
it's solarcity (I get it, they are the same now). Oh and by the way you have
to have the solarcity solar panels installed and running for the powerwall to
be installed, which has a cost of it's own.

My guess is that this isn't any different given this text:

 _Powerwall 2 is a battery for homes and small businesses that stores the
sun’s energy and delivers clean, reliable electricity when the sun isn’t
shining._

~~~
nickparker
Powerwall makes a whole bunch more sense for solar storage.

If you're just using it for backup power off the grid, you have to convert AC
-> DC -> AC again for use. I don't know the all up efficiency of that system,
but it's far from great. Probably <70%

~~~
n17r4m
The specs list it as 90% efficiency round trip.

------
mrfusion
Looks amazing! I wonder how they get wired together? How are they attached to
the roof?

------
jameshart
Interesting to see Tesla of all people estimating energy consumption on the
basis solely of how many bedrooms your house has, and not adding on how many
electric cars you need to charge...

~~~
pizza
Bedrooms generalizes better for new customers.

...additionally, who's to say a Model S isn't a bedroom in your garage? /s

------
DeBraid
Many Powerwall 2's can be combined to reach potentially unlimited scale. Tesla
working with SCE to build an 80 mWh Powerwall 2 stack.

Utility power required to partner with local generators. Bright future for
both rooftop and Big Utility.

Solar Roofs

Solar roofs superior to normal roof? Can they look better and costs less.
Maybe.

Make solar panels look like roof shingles. A textured glass tile
contains/covers (?) the solar cells.

Hydrographic printing allows each tile to look unique, so the roof/house looks
beautiful. No two roofs will be the same.

From street-level, it looks opaque, but is transparent to Sun.

------
seanlinmt
Is the patent for Powerwall v2 available somewhere as well? As per
[https://www.tesla.com/blog/all-our-patent-are-belong-
you](https://www.tesla.com/blog/all-our-patent-are-belong-you)? Just windering
if it contains enough info for anyone to built a unit themselves.

~~~
toomuchtodo
The software is the special sauce. You could build your own PowerWall easily:
it's just a battery box. The battery management system is the hard part.

~~~
davej
It's not just a battery box. There's some pretty advanced liquid cooling and
an inverter in there.

------
revelation
Direct 1080p video link:

    
    
      https://uhsakamai-a.akamaihd.net/sjc/omega/vod/sjc-566a4ba6-8cb9-4eef-9ff4-f91aa8d13adb/84771680112000/96870994920000/plain/improved/1/chunk_NUMBER_84a103284c.flv
    

Replace NUMBER with 1 to 190 or get the playlist:

[http://pastebin.com/raw/YeNr726v](http://pastebin.com/raw/YeNr726v)

------
ifhs
Brilliant. Can't wait to order one. Wonder when it will ship since I was
planning on reroofing next 4 months or so.

~~~
greglindahl
Not for a while -- he said next summer, starting in California. And all 4
styles won't be available at start.

------
Fej
How long are the batteries going to last? With phones, we expect the battery
to deteriorate after a couple of years. This is an investment. Will it need to
be replaced in a few years' time?

~~~
will_hughes
The problem with phones is that they don't have good management - the battery
doesn't have active cooling, or heating when needed. They're also charged to
full capacity or depleted to empty a lot of the time.

These things are what kills battery life.

~~~
usrusr
Phone batteries get hot, but they have plenty of thermal connection with the
environment. This is nowhere close to the magnitude of a heat problem you
would have within a massive multicell pack, where the direct environment of
one hot cell would be a few other hot cells. Active cooling is not something
you add to a pack the size of a Tesla to make it survive a few more cycles, it
needs it to survive the first cycle. But sure, once you have active cooling
you might just as well try to make it powerful enough to create an environment
that is even better than that of a single cell phone battery. Just don't hook
overboard and have the cooling power demand cut noticeably into total cycle
efficiency.

About cycle depth: Does Tesla come with an UI where you can do something along
the lines of "I need to go 200 miles the day after tomorrow, do whatever you
think is best for the battery in the time until then"? Or at least a setting
"feel free to optimize from what you learnt about my driving patterns, except
when I press the prepare-long-distance button"?

If not, most of that battery management technology will just be about not
being worse than a single cell system. In that case, the difference in
perceived durability mostly comes from a wildly different balance between
depth of discharge and expected lifetime. Phone makers are quite happy with
your batteries getting worse after two years, so they drive them over a wide
voltage range, Tesla is in a market where they can't do that.

I suspect that drivers want their "fully charged" just as much as phone users,
but I might underestimate Tesla/owners here. Maybe "battery wisdom" just needs
some time to sink in. Sony is advertising a "top off the battery only just
before the morning alarm goes off", this is the right direction (to bad that
the new compact is a downgrade)

~~~
will_hughes
> Does Tesla come with an UI where you can do something along the lines of

No, not like that.

The charge UI interface has a 'daily' indicated range that you can set, and
the top ~10% is marked 'Trip'.

Example from a screenshot of the mobile app shows what i mean[1]

The advice given to owners is to normally set the charge limit to somewhere in
the daily range depending on their expected driving needs the following day.

As stated by others, it's most damaging to cells to be kept at the extremes of
their charges. Controlling temperature is another big factor in it too, that's
why Tesla has active temperature management in the cars and stationary storage
products.

Here's real-world numbers from owners[2] and shows that the degradation even
after a lot of miles and with older packs isn't terribly much.

[1] [http://imgur.com/a/Cr0Cq](http://imgur.com/a/Cr0Cq)

[2] [https://electrek.co/2016/06/06/tesla-model-s-battery-pack-
da...](https://electrek.co/2016/06/06/tesla-model-s-battery-pack-data-
degradation/)

~~~
usrusr
Actually, that UI is pretty much exactly what I had in mind. All devices that
control their own charging should have that "trip" switch. It's a shame that
Android does not have an API to customize charge depth like that. I
occasionally spend some idle thought on wondering how difficult it would be to
overcome this limitation with a bluetooth-controlled charger. Well, I'm not an
electrical engineer and "bringing the joys of self-asphyxiation to your phone"
maybe would not be the most successful kickstarter ever either.

~~~
illumin8
Most decent smartphones are already doing battery management and avoiding
extreme draining or charging of the cells.

Think about it this way: If your phone has 8 hours of use, chances are the
battery could really give you 9 or 10 hours if it was fully charged, but the
manufacturer is software limiting it to prolong the life of the battery.

~~~
greglindahl
All things with a LiIon battery do battery management to avoid extreme
draining or charging. I've never seen a phone that offered a choice of "more
battery cycles vs slightly longer run-time".

For cars, it's not an unusual feature to be able to choose. The Leaf has that
feature, and since it cycles its small batter frequently, it's an important
consideration for owners. See:

[http://livingleaf.info/2012/07/care-and-feeding-of-the-
nissa...](http://livingleaf.info/2012/07/care-and-feeding-of-the-nissan-leaf-
battery/)

------
starchild_3001
The video:
[https://www.youtube.com/watch?v=dRqSkR4ENAg](https://www.youtube.com/watch?v=dRqSkR4ENAg)

------
andreyk
His argument about the solar roof starts by equating the situation to how
Tesla started out - electric cars were slow and ugly and needed to be sexy and
cool to be attractive, and the same is true for solar. Except I highly doubt
this is true here - do people really mind the look of typical roof-mount
solar? My impression is that the upfront cost is just too high and cost recoup
is just too slow. The argument for the solar roof is then 'using a solar roof
in the first place = way cheaper than installing on top of existing roofs (and
also it looks as good and works better)'.

Maybe? I'd like to see the quantitative argument here. Having a house pre-
built with a fancy solar roof AND a powerpack seems like it would still be
pretty much for rich people. Still, maybe the aim is for a similar trajectory
as Tesla - start with a product for rich people, make it attractive, lower
cost so everyone can have it and WANTS to have it.

Unrelated: gosh, I like the content of the video presentation but it would be
nice if Musk was a slightly better presenter.

~~~
nixarn
Every time Elon presents something we have this coversation. I for one love
listening to him talk compared to say the presenters at Apple and Microsofts
recent event. He's genuine, doesn't feel like a salesman, talks about the
reasoning and science behind it all in a great way.

~~~
davidivadavid
The content of his presentation is always interesting. The delivery is always
incredibly awkward and cringy.

~~~
nixarn
I dont agree. Not cringy and awkward, but human and real. Who cares if he
stutters and doesn't bring a polished salespitch. And he's nerdy for sure, but
why have it any other way. Also the few jokes thay occur are typically funny
as they are genuine and not silly jokes practiced before hand like Apple seems
to like.

~~~
davidivadavid
That sounds like a false dichotomy. Recent Apple keynotes are more polished,
but the content is often cringy too (that whole "courage" thing will go down
as one of the most ridiculous things ever said in an Apple keynote). Not a
good counter example.

But Louis CK sounds human and real _and_ he can deliver something without
stuttering, bad comic timing, and awkward pauses. You might say it's his job —
but that's the point. It's a job. It takes skill.

Musk is just not a good public speaker, that's all. I don't think even he
would disagree with that.

------
rjdevereux
Sounds great, I'd like to see the assumptions in the financial model that show
how it is cheaper than conventional roofing material.

~~~
greglindahl
Note that what he said is that the solar roof plus the electricity that it
generates is cheaper than a conventional roof. The up-front cost is higher for
the solar roof.

So, yes, there are assumptions in there: how much power can be generated, how
valuable will it be 10 years from now, etc.

~~~
toomuchtodo
You also now get a 30 percent tax credit to replace your roof. Before, you'd
be entirely out of pocket for the roof, separate from the solar install.

~~~
secabeen
This is big. My roof cost nearly double what my solar installs did, and
getting the tax credit on the roof might have paid for the additional cost of
the solar tiles over standing seam metal. (Not that I don't love the metal;
it's awesome.)

------
onesun
Any idea why the solar cells aren't packed more densely? It looks like there's
a lot of wasted space on due to a square cell centered on a rectangular tile.

~~~
anexprogrammer
A little over 50% of a roof tile is covered by other tiles to provide the
weatherproofing. The square solar part covers nearly all the exposed area.

~~~
onesun
That's not really how it looks in the pictures on their site. It looks more
like they are butted together with no overlap. Also, I'd think you'd want just
as much overlap on the long side for weatherproofing. This does raise an
interesting question; how are they weatherproofing this installation?

------
newman314
I'm interested in both but could not find any details what kind of output a
solar roof would generate.

Also, I would be interested in know if it's possible to walk on top of a solar
roof. People still need to be able to get on the roof to do work.

------
zappo2938
Someone posted a link about Boston.gov being released as an open sourced
project on GitHub. I'd like to take a moment to point out that this Tesla
website is built on Drupal 7 too. The big thing that both websites get out of
the box is i18n support for translation on top of all the tools required from
content management. I wouldn't recommend it for websites and services that
need many people to constantly update content but to build static pages that
are cached is pretty awesome stuff.

------
starchild_3001
Musk & co changing the world one step at a time. I used to be a Tesla sceptic.
Not anymore, having owned one and witnessed the relentless improvement in
battery tech.

------
jburgess777
Is there a summary for anyone that doesn't want to sign up?

~~~
andrewtbham
[https://electrek.co/2016/10/28/tesla-solar-roof-powerwall-
en...](https://electrek.co/2016/10/28/tesla-solar-roof-powerwall-energy-
solution/)

------
alando46
Any idea how much power these things put out when compared with a conventional
solar setup? 1:1? .5:1?

~~~
ChuckMcM
That was my question as well, this from the Techcrunch article:

 _" The current versions of the tiles actually have a two percent loss on
efficiency, so 98 percent of what you’d normally get from a traditional solar
panel, according to Elon Musk. But the company is working with 3M on improved
coatings that have the potential to possibly go above normal efficiency, since
it could trap the light within, leading to it bouncing around and resulting in
less energy loss overall before it’s fully diffused."_

Which suggests that on a square footage basis it is similar. The difference
being that on a manufactured panel the cells are all exactly next to each
other with no seams, and with the Tesla roof they appear to have a moat around
them that varies a bit with roof tile style.

That said, assuming you cover your entire roof which will include both "ideal"
south facing (or north facing in the southern hemisphere) and "non-ideal"
north facing parts of the roof you may get enough additional generation from
the extra tiles to push it over a more 'traditional' solar install.To be
honest I'm thinking about replacing my perfectly fine (if nearly 15 year old)
solar panel set up with those roof tiles. That and a couple of power walls and
I just might be able to go 'gas only' with PG&E.

~~~
mrfusion
Normal shingles have a lot of overlap right. Wouldn't most of that moat be the
overlap?

~~~
taysix
You're right. In the second tile he shows it look like 60-70% is just the
moat.

------
dabeeeenster
"Powerwall uses an internal inverter to convert DC energy to the AC energy
required for your home, lowering cost and complexity."

Does this mean that you don't need to buy a regular solar array inverter if
you are deploying it with a new solar installation?

------
Gustomaximus
A bit late to thread but;

1) I'm wondering why the tiles weren't larger? Wouldn't this make laying them
much cheaper in a world where labor is such a significant cost for building.
Aside from the shingle look I'm surprised these dont come in 1mx1m type sizes
plus some smaller sizes for edges. I cant imaging this want discussed so
curious if I'm missing some obvious logic here.

2) If you didn't have a ceiling would these let light through and further
reduce electricity usage?

3) The cells seems to be a small proportion of the tile. Is this something
they expect to increase so they will increase power generation ability
significantly over future releases?

------
gregn610
X-post from reddit as it might get an answer here...

[http://m.imgur.com/pgskG9q?r](http://m.imgur.com/pgskG9q?r)

This LNG ship got me wondering about a battery equivalent, charged up in a
desert solar farm and shipped to a major city.

I get 16 Powerpacks per 40ft container 5100 containers per Panamax ship =81600
powerpacks per ship At 95kWh per pack = 7752MWh per ship ( based on powerpack
v1)

So is that like two Hinckley C nuclear reactors worth of energy? How long
would that last before having to go back for recharging? How long would it
take to charge from a massive solar farm etc etc. so many questions but
basically, is it remotely viable?

~~~
pjc50
It's not "two Hinckley C nuclear reactors worth of energy" unless you confuse
MW and MWh. 7752MWh per ship = _two hours_ of Hinckley C.

------
nimish
Arbitrage economy 7 in the uk-- halve your electricity orice. Not bad at
all....

------
anthay
I was pleasantly surprised to see prices quoted in £GBP - the Powerwall is
available in the UK! But, we don't have enough sunlight here to run a typical
house off-grid year-round, do we?

~~~
Brakenshire
In the UK we get about a quarter of the incident energy from sunlight in
Winter than we do in Summer. You could do it by overbuilding your solar array
by 4 times over what's required in Summer. That might actually be reasonable
if solar prices carry on going down. Or you could do it by having some sort of
micro-CHP system which produced electricity and then uses the waste heat to
heat the house.

But, yeah, I think this is the major outstanding issue with renewables at the
moment. Solar with battery storage looks like it will get parity with the grid
anywhere near the equator, where you don't need seasonal storage. The UK needs
additional solutions. I think we should be putting more money into developing
micro-CHP personally. British Gas were trying out a Sterling engine system a
few years back, there are also some in development using Fuel Cells.

------
sambe
I'm not following the calculations, maybe I'm sleepy. "can power a two-bedroom
home for a full day". They say that is 20kWh (it doesn't change when you say
sockets vs entire home...). They say the battery is 14kWh and only recommend
one. Huh?

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mrfusion
@elonmusk Just a thought. How about A prebuilt shed built with these shingles
might make a good product.

A lot of people buy prebuilt sheds and if it only cost $x extra and you could
start lowering your electric bill.

~~~
dabeeeenster
You also need the inverter etc etc. So unless it was a big shed, maybe its not
viable?

~~~
mrfusion
Good point. I'd imagine you could charge an electric car without an inverter.
Perhaps it could be just for that purpose. Bury a line running to your garage.

~~~
dabeeeenster
Would it not make more sense to make houses DC?

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mrfusion
Is anyone else having trouble with the tesla website? - bunch of words are in
a different language and the prices are in a foreign currency.

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Dowwie
I suspect that Tesla will exponentially improve the capacity and performance
of these Powerwall units every couple of years.

~~~
mathgeek
Exactly the reason that many people are wise to hold off on installations. The
long term cost savings are wasted if future products are exponentially better
in the short term. Non-financial benefits aside, naturally.

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keyle
It looks so cute with its 110kg (220lbs)...

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superfx
Does anyone know where the video was filmed? It looks like it might be a
neighborhood in the Bay Area.

~~~
crb
The "Colonial Street" set at Universal Studios in Burbank, California. Most
famous as the set of Desperate Housewives.

[https://en.wikipedia.org/wiki/Colonial_Street](https://en.wikipedia.org/wiki/Colonial_Street)

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foobarqux
I thought Straubel said that the Powerwall was meant not for offpeak storage
but for emergency backup.

~~~
toomuchtodo
That Powerwall was of a different chemistry, and has been discontinued.

EDIT: This is a baller feature:

"Always Connected: Monitor your solar energy use in real-time and _receive
alerts when Powerwall is preparing for cloudy or severe weather._ "

They're performing weather forecasting, and then ensuring the Powerwall has
charged up for a possible outage event. Brilliant.

~~~
JoeAltmaier
I cannot imagine what preparation they could be making. Surely the default
process is to charge the powerwall at all times if feasible. What extra
operation could it do in the event of a bad weather forecast? Other than tell
you about it.

~~~
extrapickles
To get better lifetime out of the cells, you don't fully charge them. I bet
when bad weather is occurring soon, it charges to maximum storage capacity,
not to max cycle level.

This lets you have best of both worlds, with a minor tradeoff in unpredictable
outages you have slightly reduced runtimes.

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Dowwie
I'm very impressed by the solar roof shingles, especially the French slate
style.

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dghughes
As much as I like the idea after reading about the Note 7 and then a battery
fire at DARPA I'm not fond of a giant battery lithium-ion battery in my house.

~~~
stomato
The problems with those batteries are that cell phones pushed the limit such
that they were dangerous due to thin walls between part of the battery(ies),
and hoverboards didn't keep batteries from overcharging, which causes a
chemical reaction forming spikes that penetrate the thin walls between the
parts of the batteries that cause fires. The batteries tech itself is not a
problem; it's the design around it.

And if you think this is bad, just wait until batteries get more powerful and
there are problems. Be thankful that it only starts a small fire!

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usaphp
Correct me if I am wrong, it estimates 12,000$ for a single day of energy
backup of your home? For 12,000$ I dont mind staying one day without
electricity.

~~~
wernercd
If you generate more electricity than you use during the day, you all of a
sudden don't have an electric bill... or a drastically reduced one.

The funny thing about solar... it's not constant. Half the day is night...
then clouds/rain/etc. 24/hours of electricity is for those dry periods.

~~~
usaphp
But my electric bill is like $30-40/month, Why would I want to shell out
$12,000 for something that will become old tech in couple of years like the 1
powerwall.

~~~
daok
30-40$ is probably a very small apartment. A house (2 levels) in Quebec during
winter can go easily around 500$ because of the constant heating required.

~~~
usaphp
But you won't get much solar electricity during winter in Quebec anyway would
you?

~~~
cstejerean
Cooling a house during the summer in Texas can easily cost the same amount if
not more, and you get a ton of sun during that time. The point is that for
single family homes electricity does not usually cost $40/month.

~~~
usaphp
But the price for the equal amount of power walls needed for a bigger house vs
a small 1 bedroom raises too, according to the calculator on their site it
will cost $30k+ to install it for 4 bedroom house.

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donclark
Are the solar cells and powerwall shielded by any kind of solar storm? I
couldnt find any detailed information confirming or denying it. I would not
like for any of us to be in a situation where the 1st solar outtage is our
most damaging, and thats what causes any producer of electronics to adopt
labeling and marketing for it.

~~~
hliyan
Radiation spikes caused by solar storms

1\. Are not in the visible spectrum

2\. Do not reach the earth surface in appreciable amounts

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Uptrenda
You can buy 12v 250ah deep cycle AGM batteries from China for around $5 per
battery -- lets assume another $15 for world-wide shipping. These kind of
batteries would have around 3kwh of storage per battery but since you
shouldn't discharge them to more than 50% lets also say that you need to
double the number of batteries to achieve 14kwh of usable power for 28kwh of
total capacity. At that capacity level, you would need only 9 batteries for a
sub total of just $180 USD (including shipping.)

Lets proceed with these calculations and say that you also want a good quality
"grid-tie" "pure sine wave" inverter (to feed your stored energy back to your
home grid) which will set you back any where from $100 - $1000. Your total
cost for energy storage is still only going to be around $1180 (worse case.)
Now consider that the life time for the Tesla batteries and standard AGM
batteries seem to be very similar and I honestly have no idea what the
customer is actually paying for.

Is the compact size and sleek appearance really worth the extra cost to the
customer? Maybe it is. Maybe people don’t want to have a nerdy battery bank in
their homes but to me the benefits all seem a little petty. (Granted, I
definitely do see the benefit for tech like this in electric cars though,
don’t get me wrong.)

~~~
doikor
And once your self made cheap chinese battery pack ends up catching fire and
taking your whole house with them you understand why you want to pay for some
actual company to do this and have some quality control/insurance.

~~~
sfblah
Yeah because Lithium Ion batteries never catch fire.

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Annatar
So I used the calculator on Tesla's web site, in my case, I'd want 3
powerwalls and I'd want a solar installation to complement it: $18,000 USD.

That's still way too high: $1,800 - $2,500 would have been acceptable. That is
how much I'm willing to pay for some solar panels, three batteries, and a
little bit of electronics (processed sand) to control the lot.

As far as I'm concerned, this is all still hype. Prices need to go down,
waaayyy down, and the profit margin and the engineering needs to be
recuperated through volume. The days of fat profit margins and the early
adopters amortizing the research and development have come and gone. The
computer industry learned that lesson the hard way; it would be a shame if Mr.
Musk repeated the same mistake, instead of learning from history.

~~~
maxerickson
A more interesting metric might be months of pay back time. $1,800-$2,500
seems like an arbitrary number you made up.

Like if your power bill averages $150 (I realize it probably doesn't) and you
plan to stay in place for a few years, then something like 50*$150=$7500 is
easy to consider and is much higher than the numbers you tossed out (that's
just over 4 years to pay you back).

I mean, I agree with the point you are implying, that people won't be
overwhelmingly excited with solar until the payback goes below 2 or 3 years,
but I think it also makes sense for longer payback times.

~~~
Annatar
_A more interesting metric might be months of pay back time. $1,800-$2,500
seems like an arbitrary number you made up._

It _is_ an arbitrary number I made up!

Which part of _that is how much I am willing to pay_ requires additional
clarification?

 _I mean, I agree with the point you are implying, that people won 't be
overwhelmingly excited with solar until the payback goes below 2 or 3 years,_

That's exactly right, and more: I am _not willing to amortize their research
and development costs outright_. That's something Tesla (or any other company,
for that matter) will have to do over years, at least as far as _my wallet_ is
concerned. Amortizing research & development costs outright is just pure
greed; I won't support it.

~~~
maxerickson
_It is an arbitrary number I made up!_

My point is that this is not really a good way to make financial decisions. If
you've bought a house and plan to stay, spending up front to save over a
decade is something to work at. Consider the rule of 72. Something that pays
back in 10 years is yielding a roughly 7% return. That's a great return. As I
said, I'm right there with ya on waiting until it makes good financial sense
to make such purchases, I just think it is also a good idea to do some
analysis to figure out what that means (and if the purchase makes sense, who
cares what it means to the company selling).

