Tesla Powerwall, The Specs, Numbers, and Implementation Absolutely Brilliant

[tehan]

IMO as of today the Powerwall is not ready for prime time.

Meaning what? You don't think the demand exists yet, or you don't think the product will reliably meet specifications?

[SunEagle]

Tesla's cars have demonstrated that lithium chemistry combined with thermal management and intelligent charge/discharge control deliver extended cycle life with minimal degradation.

It's hard to predict what might be "justified by the majority" because incentives are so varied. Some are paying 8c per kWh for grid power, others 40c per kWh. Some see almost no value in grid backup, for others it is literally the difference between life and death. But I can certainly imagine over the next 10 years say 10% of US homes will install solar panels, and perhaps half of those may see value in adding a battery. That is a very large market opportunity indeed.

I have to agree that there will be more US homes with solar panels and some type of energy storage device. Those that have high electric costs or critical loads will be first in line to install that energy storage device.

Battery technology is still growing so who knows what will happen in 10 years.

IMO as of today the Powerwall is not ready for prime time.

[Willy T]

I'm not the one arguing from authority. I'm happy to have a factual discussion about the merits of Tesla's solution. But comments like "I see a write up on the concept a few weeks ago on a Engineering web site ripping the idea to shreds because it is full of holes and would be incredible expensive to implement." don't add much to the debate.

Especially when you see them over on a DIY EV forum site trying to get Information to back up what they are posting on here. It doesn't add much credibility of their knowledge about the Tesla battery.

http://www.diyelectriccar.com/forums/showthread.php?t=157449

[tehan]

My big question, what is the "true" cycle life of those batteries and will it ever be cost justified by the majority for residential usage?

Tesla's cars have demonstrated that lithium chemistry combined with thermal management and intelligent charge/discharge control deliver extended cycle life with minimal degradation.

It's hard to predict what might be "justified by the majority" because incentives are so varied. Some are paying 8c per kWh for grid power, others 40c per kWh. Some see almost no value in grid backup, for others it is literally the difference between life and death. But I can certainly imagine over the next 10 years say 10% of US homes will install solar panels, and perhaps half of those may see value in adding a battery. That is a very large market opportunity indeed.

[SunEagle]

I agree the marketing around the launch was overblown and ridiculous. But look, Tesla can manufacture maybe 200,000 units in the next couple years. They aren't trying to sell to Joe Homeowner anymore than they are trying to sell cars to Joe F150 driver. The initial market for PW is (i) regions like Germany/Australia/Hawaii where the value of time shifting solar production is very large (>30c per kWh) and (ii) backup power needs that can't be met with generators. I don't know how big these markets are but I suspect they are plenty big enough for PW to establish an initial foothold. I know that I, for one, cannot deploy any type of generator because of local setback and noise ordinances.

As for technology, Tesla's solution is vastly superior to existing solar battery solutions because (i) it uses a lithium chemistry, and (ii) it operates at a voltage (350v) that is optimal for residential power distribution instead of a voltage (48v) that was selected 100 years ago as the line voltage for telephones. All the other technical arguments are pretty much noise compared to those two.

While it is a good direction for the battery operating voltage going up as well as being an option for those that are not allowed to install and use a generator for emergency power. That battery technology is still very expensive.

My big question, what is the "true" cycle life of those batteries and will it ever be cost justified by the majority for residential usage?

[tehan]

I agree the marketing around the launch was overblown and ridiculous. But look, Tesla can manufacture maybe 200,000 units in the next couple years. They aren't trying to sell to Joe Homeowner anymore than they are trying to sell cars to Joe F150 driver. The initial market for PW is (i) regions like Germany/Australia/Hawaii where the value of time shifting solar production is very large (>30c per kWh) and (ii) backup power needs that can't be met with generators. I don't know how big these markets are but I suspect they are plenty big enough for PW to establish an initial foothold. I know that I, for one, cannot deploy any type of generator because of local setback and noise ordinances.

As for technology, Tesla's solution is vastly superior to existing solar battery solutions because (i) it uses a lithium chemistry, and (ii) it operates at a voltage (350v) that is optimal for residential power distribution instead of a voltage (48v) that was selected 100 years ago as the line voltage for telephones. All the other technical arguments are pretty much noise compared to those two.

[Sunking]

I'm not the one arguing from authority. I'm happy to have a factual discussion about the merits of Tesla's solution. But comments like "I see a write up on the concept a few weeks ago on a Engineering web site ripping the idea to shreds because it is full of holes and would be incredible expensive to implement." don't add much to the debate.

It does if you understand engineering and electronics design principles. That is why you cannot have a debate on a DIY site when most of the members have no understanding of the subject material. All they hear is what they want to hear and drool with no clue what they just heard or talking about.

[SunEagle]

I'm not the one arguing from authority. I'm happy to have a factual discussion about the merits of Tesla's solution. But comments like "I see a write up on the concept a few weeks ago on a Engineering web site ripping the idea to shreds because it is full of holes and would be incredible expensive to implement." don't add much to the debate.

True. That statement might not add much to the this debate but I have also read a number of articles (from different engineering sources) that poke big holes in the marketing advertisements that have come out of Tesla for their Powerwall battery.

The concept is ok but IMO based on what they have "engineered" is not ready for public consumption in the US. Maybe there is a version for Europe and maybe only the POCO's here in the US will purchase it.

As it stands now, the Powerwall technology will not work as advertised for Joe Homeowner and based on the cost is too high for most people to purchase or justify.

[tehan]

Hmmm. Trusting a multi-billion dollar making company would seem to be a good idea. Please tell that to all the people that trusted Enron with their investments.

Maybe you need to stop believing in the fancy advertising from Musk and do some research into what the design involves to install and safely run a complicated yet low cost battery system. That technology is still being developed.

I'm not the one arguing from authority. I'm happy to have a factual discussion about the merits of Tesla's solution. But comments like "I see a write up on the concept a few weeks ago on a Engineering web site ripping the idea to shreds because it is full of holes and would be incredible expensive to implement." don't add much to the debate.

[SunEagle]

Yeah right. Because who are you going to trust: the company with the $30bn market capitalization and unlimited access to the best of Silicon Valley engineering talent, or the retired blogger sitting in his kitchen tapping away at his Chromebook?

Hmmm. Trusting a multi-billion dollar making company would seem to be a good idea. Please tell that to all the people that trusted Enron with their investments.

Maybe you need to stop believing in the fancy advertising from Musk and do some research into what the design involves to install and safely run a complicated yet low cost battery system. That technology is still being developed.

[J.P.M.]

Actually, that is not a 100% obvious choice, given the nature of Marketing.

And the nature of some of what's supposed to pass for engineering.

[tehan]

Sure, marketing people make unsupportable technical claims all the time. But that's not what was asserted. The claim was that the Tesla/SolarEdge engineers don't know what they are doing. I find that unlikely.

[inetdog]

Yeah right. Because who are you going to trust: the company with the $30bn market capitalization and unlimited access to the best of Silicon Valley engineering talent, or the retired blogger sitting in his kitchen tapping away at his Chromebook?

Actually, that is not a 100% obvious choice, given the nature of Marketing.

[tehan]

You think?
I see a write up on the concept a few weeks ago on a Engineering web site ripping the idea to shreds because it is full of holes and would be incredible expensive to implement.

Yeah right. Because who are you going to trust: the company with the $30bn market capitalization and unlimited access to the best of Silicon Valley engineering talent, or the retired blogger sitting in his kitchen tapping away at his Chromebook?

[Sunking]

Cool - thanks for the link. The PowerWall architecture would presumably be different since each PowerWall outputs 350V nominal, so stringing together PowerWalls in series as shown in the SolarEdge StorEdge document you posted doesn't make sense.

You think?

The concept for home use is in parallel with a gizmo that does not exist to make the batteries share load and isolate weaker battery packs. I see a write up on the concept a few weeks ago on a Engineering web site ripping the idea to shreds because it is full of holes and would be incredible expensive to implement. Can it be done yes. Would anybody buy it is the question? There are much less expensive and less complicated ways to get the same job done.

Geez liquid cooling in an off grid or back up system? What are they thinking? No wanother gizmo needed to make it work. Absolutely brilliant. See how deep they can get their hands in your pocket. Rube Goldberg would be tickled pink if he was alive today, and PT Barnum is laughing in his grave wishing he had thought of that.