PowerWall and "The Missing Piece..." Event

[matbl]

Try to think in shades of gray and not only in black/white.
Yes, 2kW is lowish by itself but when added to 3kW from grid it becomes 5kW with only 3kW grid connection.
Two units become 7kW.

Here in my part of the world we pay for electricity in three parts:
- maxim line power (breaker rating): fixed price/month
- transportation: we pay ~$0.10 per each kWh supplied to our home at 3kW max. Higher breaker ratings have higher transportation cost.
- consumption: we pay another ~$0.10 per each kWh "consumed" at 3kW max. Price is again dependent on breaker rating.

So, in the end we are charged three times for each kWh consumed. This scheme is set up so that small residential (flat) owner/renters pay low electricity bills but larger consumers end up paying superlinear rates.

Buying a tesla means a fatter breaker to be able to charge with 8kW and higher cost per kWh. With two daily units for $6k one can skip upgrading power feeds to his garage. ROI can be less than 2 years.

I'm glad tesla didn't draw things out to opaque, I might still have oportunity to grab some more shares before they skyrocket...

Wow. With those prices and low breaker ratings this would be a good thing to have I guess.
but with two units, you can just pull 4 kw from them?

and to put things in perspective, while we have the same three part thing in this part of europe, prices are somewhat different.
I have 3*25A breakers so at 240V, 3*6 KW.
transportation: $0.03 per kwh. Consumption: ~$0.08 per kwh ($0.03 is energy, $0.05 is taxes).

 

[deonb]

Wait a second... something's wrong here.

If you can't draw more than 2kW of power from the battery, you probably also can't put in more than 2kW of into it.

So now you need to convince 2 kW of Solar Panels to generate 7kWh per day... That's a bit on the high side for the Northern states.

Sure, you can oversize the panels to bring up the non-peak hour output. But then what?

E.g. let's say you have 9 batteries, and use 25kW of Solar panels so that you can actually fill up those batteries in a day. What do you do with that extra 7 kW during the peak hours that you can't actually store in the batteries? Party like it's 1999?

You could sell it back to the utilities, but then what's the point of having a daily battery?

 

[Metalbird]

Powerwall - Tesla's Energy Storage for a Sustainable Home

Not sure if posted somewhere else on this forum, but Tesla just went live on their official website for Powerwall:

http://www.teslamotors.com/powerwall

"Powerwall is a home battery that charges using electricity generated from solar panels, or when utility rates are low, and powers your home in the evening. It also fortifies your home against power outages by providing a backup electricity supply. Automated, compact and simple to install, Powerwall offers independence from the utility grid and the security of an emergency backup."

Deliveries begin this summer but you can reserve one now!

Prices:
10 kWh model: 3,500$
7 kWh model: 3,000$

For people having solar panels installed, this seems like a decent investment. Does someone own a sufficient amount of solar panels to move away from your energy supplier and would you buy it?

-David

 

[zag2me]

Anybody got a link to a recording of the event. It was a bit too early for me (5am).

Hit "watch again" here

Tesla Motors Livestream | Tesla Motors

I'm not sure I've ever heard such a game changing technology. It reminds me of when apple released the iPhone.

The idea of helping people in 3rd world countries get independent power just blows my mind. Let alone the commercial scale rollouts and boost this is going to give solar all over the planet. And then there was the price, half of what people expected.

Amazing!

 

[InTheShadows]

Wait a second... something's wrong here.

If you can't draw more than 2kW of power from the battery, you probably also can't put in more than 2kW of into it.

So now you need to convince 2 kW of Solar Panels to generate 7kWh per day... That's a bit on the high side for the Northern states.

Sure, you can oversize the panels to bring up the non-peak hour output. But then what?

E.g. let's say you have 9 batteries, and use 25kW of Solar panels so that you can actually fill up those batteries in a day. What do you do with that extra 7 kW during the peak hours that you can't actually store in the batteries? Party like it's 1999?

You could sell it back to the utilities, but then what's the point of having a daily battery?

The output specs look to me like the specs you would see on a string of solar panels.

Perhaps it is installed between solar panels and an inverter. Thus keeping installation cost low and making it extremely easy to be retrofit.

It would be interesting to see if it has its own MPpt solar charge controller built into it. I would think it could because of the BEM.

This could help tremendously for the gray area in the 30% federal tax credit.

 

[Ampster]

Your critical loads have to be connected to the Outback Radian yes? For many existing homes, that's going to be quite difficult and expensive? Especially, if the critical loads is off of a subpanel say in the master bedroom? How much was the Outback Radian? Couple thousand at least right?

Yes, I moved my critical loads to a new sub panel. These were the loads that were using about 500 watts an hour. The Radian powers the sub panel until my batteries reach the set point and then the Radian switches back to powering that panel from the grid. At the beginning of my cheap off peak rate my charger comes on and brings the batteries up and the cycle starts over when rates are high.
I haven't seen many homes with a sub panel in the bedroom but if that is too much trouble then don't do it. I find it difficult to pay Southern California Edison $0.47/kWh when I can use this system to load shift and charge with $0.11/kWr power.
Life is expensive. We all have choices where or when we spend our money.

 

[InTheShadows]

Yes, I moved my critical loads to a new sub panel. These were the loads that were using about 500 watts an hour. The Radian powers the sub panel until my batteries reach the set point and then the Radian switches back to powering that panel from the grid. At the beginning of my cheap off peak rate my charger comes on and brings the batteries up and the cycle starts over when rates are high.
I haven't seen many homes with a sub panel in the bedroom but if that is too much trouble then don't do it. I find it difficult to pay Southern California Edison $0.47/kWh when I can use this system to load shift and charge with $0.11/kWr power.

This system is designed differently. The radian takes a 48v input. Tesla just redid how battery backup is accomplished. That is why they partnered with SolarEdge.

 

[Ampster]

This system is designed differently. The radian takes a 48v input. Tesla just redid how battery backup is accomplished. That is why they partnered with SolarEdge.

Yes most big inverters are 48v and I wondered how that would work with the high voltage of this battery. Then I saw that the battery had a DC to DC converter. Or are you saying Solar Edge is making a 350v inverter?

 

[InTheShadows]

Yes most big inverters are 48v and I wondered how that would work with the high voltage of this battery. Then I saw that the battery had a DC to DC converter. Or are you saying Solar Edge is making a 350v inverter?

Solar edge optimizers run at exactly 350v.

That voltage and power range are right in the sweet spot for all modern string inverters. My hunch is that it has mc4 connectors and just plugs in between the solar inverter and the solar panels.

It probably has other options too which is what the dc converter is for. The most efficient way to do it though is straight at 350v dc.

Wires are much cheaper at that voltage as well.

 

[Ampster]

Thanks for the clarification. I guess I won't be buying a wallpower. The concept is the same however. That sweet spot must also mean there is less loss charging and discharging.

 

[ItsNotAboutTheMoney]

Wait a second... something's wrong here.

If you can't draw more than 2kW of power from the battery, you probably also can't put in more than 2kW of into it.

So now you need to convince 2 kW of Solar Panels to generate 7kWh per day... That's a bit on the high side for the Northern states.

Sure, you can oversize the panels to bring up the non-peak hour output. But then what?

E.g. let's say you have 9 batteries, and use 25kW of Solar panels so that you can actually fill up those batteries in a day. What do you do with that extra 7 kW during the peak hours that you can't actually store in the batteries? Party like it's 1999?

You could sell it back to the utilities, but then what's the point of having a daily battery?

Around here, which isn't the NW Washington Dark Zone, but still not great, PVWatts says 1kW peak can average 3.4kWh/day, and that includes the winter months which really suck. If anything the problem with a 7kWh/2kW battery is that the battery isn't big enough.

 

[pgiralt]

It likely includes a small inverter AC to DC to charge the battery from the grid slowly, ...

Sorry to nitpick but it would be a rectifier that converts AC to DC, not an inverter. I'm guessing the pack does contain the charge controller and rectifier pieces, but it's not spelled out

 

[wycolo]

Great to see Elon quantifying the world's energy needs and showing that small blue square representing the tiny share of the world's surface needed for a solar solution to that World Energy Need.

Elon: The Grid soon to become irrelevant similar to copper phone lines currently being unnecessary & redundant.

Elon defining the new standard for battery packs: 350 volts DC - same as Tesla car batteries. Finally we have a DC standard to go along with the 240/480 volt AC standard (North America).

Elon defining scalability: 1 to 9 Little Batteries as needed, then you step up to a Big Battery (or more).

Thank you Elon!
--

 

[Gtoffo]

Regarding the "lack of details" that some users have brought up: you are wrong....and that is because we are not normal consumers.....we are nerds.

People used to criticise Apple presentations for not showing all the product specs (sometimes they still do). Consumers don't want to be bothered with all the details about installing this thing. They will just pay a company to do it (Solarcity?).

The presentation communicated that the cost will be around 3000$+installation.

Consumers don't care about which inverter they will need. And they shouldn't care. That's why companies like Solarcity exist.

We care....but we are nerds

Also, it doesn't seem like they will have a lot of residential battery packs available for the next 12 months. As others have said, this was sort of a "product reveal/preview." More details can come at a later date. As well as solutions for the masses instead of just the early adopters.

I liked the event. I'm excited by the future of Tesla.

 

[Bgarret]

Regarding the "lack of details" that some users have brought up: you are wrong....and that is because we are not normal consumers.....we are nerds.

People used to criticise Apple presentations for not showing all the product specs (sometimes they still do). Consumers don't want to be bothered with all the details about installing this thing. They will just pay a company to do it (Solarcity?).

The presentation communicated that the cost will be around 3000$+installation.

Consumers don't care about which inverter they will need. And they shouldn't care. That's why companies like Solarcity exist.

We care....but we are nerds

Also, it doesn't seem like they will have a lot of residential battery packs available for the next 12 months. As others have said, this was sort of a "product reveal/preview." More details can come at a later date. As well as solutions for the masses instead of just the early adopters.

I liked the event. I'm excited by the future of Tesla.

It's also helpful to judge the presentation if you realize Elon wasn't selling anything. It wasn't a sales presentation, filled with details to close the business, I am guessing they have another business that is supply constrained. Until the gigafactory is fully up, I don't think they will be able to meet demand. Why go into excruciating detail to "stimulate" demand you can't meet?

 

[bp1000]

I think you can only reserve one if you live in the U.S.

 

[deonb]

Regarding the "lack of details" that some users have brought up: you are wrong....and that is because we are not normal consumers.....we are nerds.

People used to criticise Apple presentations for not showing all the product specs (sometimes they still do). Consumers don't want to be bothered with all the details about installing this thing.

This is very different.

With an Apple product you customize yourself to that product. If you don't want to, you don't buy it. Same with a Model S. If you want a car that is lighter, or can tow an RV, or fit into a compact parking space, the Model S is not for you and you just don't buy it.

It just so happens that there are enough people who can make themselves fit to the product to make it worthwhile.


A house however is vastly different. It's the epitome of customization. No 2 homes (or at least no 2 complexes) are the same. They have different electrical needs, different peaks, different rates, different solar coverage etc. You really do need to spend some time learning it to make sure it works. Unless you're going to have a SolarCity guy live with you for a few months to see how you live and what is important to you.


I have a Nest. But I also keep flex hours right now and have a rotating day of around 26 hours. This makes Mr. Nest very very unhappy. But I'm not going to change my schedule to make the Nest happy. And I'm similarly not going to be happy with an off-the-shelve solar installation that I can't customize.


"The reasonable man adapts himself to the world; the unreasonable one persists in trying to adapt the world to himself. Therefore, all progress depends on the unreasonable man." - George Bernard Shaw

 

[deonb]

I know you're new... but posting information about Tesla 5 hours after it was announced and thinking you're the first... how cute .

 

[Gtoffo]

This is very different. [...]
If you don't want to, you don't buy it.

Not different at all then

This is a big market and Tesla has a small supply (at the moment). Priority should be on commercial applications at the moment.

The consumer product offers scale (it's modular) and adaptability (bring your own inverter etc.). If you still don't fit the product. Don't buy it.

 

[deonb]

Not different at all then

This is a big market and Tesla has a small supply (at the moment). Priority should be on commercial applications at the moment.

The consumer product offers scale (it's modular) and adaptability (bring your own inverter etc.). If you still don't fit the product. Don't buy it.

Right, but for modularity and adaptability we need technical specifications on how it works in order to bring your own inverter etc...