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You are missing something. The HD Wave is using a distributed multi-level stepped output to produce something much closer to a sine wave before filtering and smoothing. This increases efficiency and reduces the quantity of magnetics required since it is transferring most of the analog signal...

I think you are on to something. Tesla has been successful with its car, in no small part, because the battery is much bigger than the competition. Perhaps even bigger than most people need. And a high price hasn't seemed to matter too much. Maybe they should have taken the same approach...

Cool thoughts. Quite a bit of smarts needed for the inverter to determine when to store excess power in the batteries and when to export to the gird. As OP question illustrates, power management needs are likely to be varied and complex. Export algorithm may depend on some or all of: time of...

SolarEdge are using powerline communication for their "Storedge" product. It's certainly possible Tesla is using this for PW also. But my guess is they will probably use RS485 instead. Most inverters, including SE and Fronius, already have a port for this. And the benefit of avoiding an...

Not at all, I'm a fan. But the quotes you provided support what I said: his existing implementation is based on off-the-shelf charge controllers, he knows this is a problem, he is building his own BMS, this is not a trivial task.

The WH057 thread is probably the most awesome discussion on this board. What he has done in amazing. But I'm not convinced his battery is going to last 10 years. He has basically removed/disabled the sophisticated Tesla battery management system and replaced it with off the shelf charge...

There are significant technical issues with connecting batteries in parallel. It's certainly is not an architecture that scales to utility level. Tesla has confirmed PW contains a DC-DC converter and it is hard to see why if it is just a dumb 350V battery as you suggest. And technical details...

As I say, I think you will find it works in exactly the same way as the SolarEdge optimizers. The SE optimizers are connected in series and the output from the string is a constant 350V volts regardless of how many optimizers are in the string.

I don't think any of those three statements is true. The Powerwalls work very much like the SolarEdge optimizers: they connect in series, but the total voltage of the string is constant. And so it's perfectly possible to control the voltage and power delivered by each unit. My interpretation...

I have my eye on something very similar: 3 kW PV /10 kWhr PW mostly as a grid backup system. I also received the same confirmation email but no call from SC; I don't even think they operate in my area. Any more details from your SC contact on system design/performance/cost?

Sure, they state 10 year life. But that's at 1,000,000 cycles. They don't provide any data on the relationship between cycles and life years, but it seems reasonable to assume that if you only cycle it once a day then the life would be a lot longer and the capacity reduction much smaller.

As I said, the problem is an 85 kWh super capacitor pack using current technology would be bigger and heavier than a lithium battery pack. You might imagine super capacitors would benefit from the same miniaturization as other solid state electronics, but that really isn't the case. As you...

This is great. Let's hope MB and Tesla cooperate so their batteries are compatible (supported by the same inverters etc.). In particular I would like to see MB support high voltage DC (350V DC) to help establish this as a standard. There's plenty of opportunity for both MB and Tesla if they...

Actually you use a variable frequency drive. Super capacitors operate at a voltage of about 3v. So you can imagine assembling many of these in series/parallel to form a pack operating at say 600V rather like the Tesla pack works today with lithium cells. You then connect the output of the...

Umm...Ohm's Law.

That Lennox unit is really nice, but the bundling with solar is mostly smoke and mirrors. It's an AC unit (as in alternating current, not air conditioning) that they are putting together with an Enphase-based solar solution.

I have no inside knowledge on the politics of this issue, but I certainly don't have much confidence the credit will be extended in the current political environment. I suppose it probably depends on the outcome of elections next year. Planning on getting my Powerwall/PV in place before the...

Good point, so ability to regulate PV production is also a requirement , since you otherwise may not have anyplace to put it. But again, the SolarEdge inverters can certainly already do this (because they can just turn off optimizers as needed) and I suspect most other grid-tie inverters with...

"AND an off-grid inverter needs to isolate itself from the grid to work off-grid. How the PW intends to do this remains to be seen..." Sure, it remains to be seen. It looks like SolarEdge will demonstrate it at Intersolar next month. But it's not exactly rocket science is it? (Though of...

Shame. I only read the Guardian article which contained the deeply misleading line "In the short term, the plan provides an ideal solution to global warming". The New Scientist article is rather more interesting and much more accurate.

Surely it would fix the Global Warming issue, no? Move to a more distant orbit, reduce solar irradiance, lower temperature. How far would you have to move the Earth's orbit to say reduce mean temperature by 2 degrees? Can't be all that far - Mars is absolutely freezing!

Kinda cool. You can't do that on a Tesla!

Is there actually any way to tap the high voltage battery on a Prius? All the kits I have seen tap the 12v battery, meaning lower voltage and much less power :confused:

Cleary it needs new hardware, but from the horse's mouth: "Designed to manage both functions with just one SolarEdge DC optimized inverter, the solution will allow for outdoor installation and will include remote monitoring and troubleshooting to keep operations and maintenance costs low. The...

I sort of assumed the reason you had 8 inverters in the first place was to provide startup overhead for the AC. Do you actually have 55kW of load? It was sort of my point that you had to go low voltage because that's what the currently available off-grid inverters support. But SolarEdge and...

"As for voltage sag, under 55kW load (highest I've been able to put on the inverters) I see about 1.3V sag on the DC side (MATE3 is only good in 0.4V increments and shows a 1.6V sag). Not bad considering that's about a 1400A load." I think that's the best you could have done in the...

One of the nice things about SolarEdge's architecture is that the optimizers are already an accurate voltage regulator controlled by the inverter. And that's really all you need for a charge controller. So I think their plan is to just plug Powerwall into one of the DC ports on the inverter...

Oh yeah, still no way this works for me on economics alone. But adding the solar does seem to lower the cost and increase the value of the backup. I too have seen the speculation that it may not be possible to charge the battery when the grid is down. I'm not convinced, but I guess we will...

I'm interested in Powerwall for backup; in fact, I was one of the first to click and "order" one. After further research, it strikes me if you are going to buy Powerwall for backup you almost certainly should add a small solar system, even here in Houston where there are no local incentives and...

"It seems to me that no great magic is needed (though there's the usual devil in the detail to make it stable). In particular, there's no communication needed - the right voltage just comes out in the wash." It's certainly possible to do MPPT at the module level in a string without...

Yeah, I think that AC Coupling paper is just putting lipstick on a suboptimal technical solution. Enphase has even talked about launching an AC Battery (see AC Battery - Enphase Energy) which is clearly a technology that came out of the marketing department! I'm sure Enphase could adapt their...

I think the reliability issue with inverters is not so much power as frequency. Connecting to the grid requires 60Hz AC which means a big electrolytic capacitor, and electrolytic capacitors are unfortunately prone to failure. It's true, as others have said, that DC-DC conversion is done with...

Presumably. There are several other product features that may not be essential but would certainly be nice to have. My ideal inverter for backup power would support any combination of Powerwall, solar and a portable generator as power sources during grid failure and would seamlessly connect...

Yes, it requires communications between the optimizers and the central inverter. They use powerline communication (PLC) for this; I believe Enphase does too. I hadn't heard of SolarEdge before the Tesla announcement, but I definitely think they were a great choice of partner for Tesla. Both...

Cool. DC-DC roundtrip efficiency just means measure the DC power in when charging and DC power out when discharging. If that isn't what your figures are based on, what are you measuring? I agree with you that moving parts means friction, heat, and reduced efficiency. But the chemical...

There a technical note here that explains it a bit: http://www.solaredge.com/files/pdfs/se_application_fixed_string_voltage.pdf I think it's more or less your second "magic" option.

Batteries don't get 99% round trip efficiency. Tesla isn't even claiming anything close to that. I suspect you are evaluating Model S based on information you are getting from the user display - you really need to measure the battery directly if you want to know the real story. I've seen...

Why would you think other systems would have worse efficiency? Large scale hydro and compressed air systems in place already have better round trip efficiency than batteries, and improved systems are coming along. Oh, and batteries aren't sold state: they're chemistry. But just to be clear, I...

The total electricity storage currently available to utilities is huge and growing. It dwarfs the in-home market. There are many technical solutions other than batteries that work at a utility level: gravity-based solutions, compressed air, flywheels etc.. And I suspect Tesla will sell more...

Actually the Power Optimizers are connected in series. They use clever electronics so the current through the optimizers is the same but the current through the panels is different. Net result is you have high voltage DC coming off the roof so the losses are very low. Don't know where you got...

As the CEO of Generac pointed out, the economics of PW for backup are not great compared to NG generators. But there are many people, myself included, who can't install a permanent generator for space reasons. And portable solutions are, as you say, crazy noisy dirty. So, yeah, I'm definitely...

Micro-inverters were a cool idea, but they don't make much sense once you add a battery into the equation because you really want to keep everything DC at least until you reach the battery. That's why SolarEdge is splitting the micro-inverter functionality into two parts: a DC-DC converter (the...

iTunes does not support FLAC. AAC offers much higher quality than MP3 and is supported on Model S. Use 256kbps for best sound quality.

Barbja - I believe you are correct that this is the sales tax exemption that some may have claimed. And you are right that if this exemption applies to Model S then it would apply to any plug-in electric. It's not the most aggressive tax avoidance scheme I have ever seen, but it is aggressive.

Hmm.. Those circle things in your photo of Columbus don't really look like anything in the Harris Ranch photos. I'm guessing, but I think they may be foundations for five circular columns that will have a platform above them, with the Superchargers then sitting on top of the platform. Fairly...

Maybe I'm just dumb but I still don't get it. If those are supports for electronics, rather than supports for bays, then why are they spaced so unevenly? The front two look really close together whereas the one at the back is quite a distance from any of the others? Still, nice to have...

@moorelin - Very cool, but am I the only one who can't understand how a car is going to access a supercharger on that back support??

I have seen charts like that for PC power supplies too. I believe more efficient modern designs tend to retain their highest efficiency up to much higher loads. In Model S you also have to consider that charger losses are about equal in magnitude to internal battery losses, and these battery...

Tesls monitors battery temperature during charging. If the combination of high charge rate and high air temp causes the battery temperature to move above spec, I would assume they back off on the charge rate to stay within spec. So yes, you might charge a little slower on a really hot day but...

Model S battery has active liquid cooling, Leaf is air cooled. End of story.