Grid tied solar system.

[inetdog]

Is this not a diagram of a split phase system or is it something else?

http://www.samlexamerica.com/support...chCircuits.pdf

You can indeed use a single ended 120V GTI on a grid connected split phase 120/240 system because the utility grid will provide all of the current on the other hot wire. With a UPS, even a grid interactive UPS, the output goes only to the loads and the utility grid cannot provide the neutral and L2 current needed.

[posplayr]

http://www.victronenergy.com/upload/documents/Datasheet-Autotransformer-32A-and-100A-EN.pdf

As Beroe mentioned earlier an Autotransformer is required generally for load balancing. You just have to pay extra.

[posplayr]

Here is the data sheet showing "Hardwired Connections"

http://www.apcmedia.com/salestools/ASTE-6Z8LVK/ASTE-6Z8LVK_R7_EN.pdf?sdirect=true

I'll admit to not understanding the data sheet they show a circled ground on the input and a bare ground on the output. The difference in ground I don't know but apparently N is neutral and something else.

[posplayr]

The model linked does not support split phase operation. The fact that the output connection is only 3 wire (two hots + ground) as opposed to 4 wire (2 hots + neutral + ground) is a good clue.

Is this not a diagram of a split phase system or is it something else?

http://www.samlexamerica.com/support/documents/WhitePaper-120240VACSingleSplitPhaseandMultiWireBranchCircuits.pdf

[sensij]

http://www.ebay.com/itm/APC-Smart-UP...item25a9c38ea8

The model linked does not support split phase operation. The fact that the output connection is only 3 wire (two hots + ground) as opposed to 4 wire (2 hots + neutral + ground) is a good clue.

[posplayr]

I'm not going to go find the datasheet for that specific model. But I am very familiar with the UPS units typically found in datacenters and no, they generally do not support split phase operation.

Can't answer a specific question for a specific model as you can't be bothered to click on the link (I provided by the way) on a model that you presumably already know about? Why do you even bother to answer?

[posplayr]

I'm not going to respond to all the points in your long-winded and boring post. But most everything you say is wrong. And look, don't take my word for it. Go research the product roadmaps for Fronius and SolarEdge, both of whom have announced and publicly demonstrated GTI models with off-grid capability. In both cases, these products are based on modest adaptations to their existing GTI designs, not on the absurd UPS scheme you have suggested. There are many reasons this approach is superior: some economic, some safety-related, and some related to desirable product capabilities. But I really have no interest in debating any of this with you while you continue to have your "dickishness" level set to 11.

Tapped you out I guess.

[tehan]

Are you saying this double conversion 240V UPS will not handle a typical household load imbalance? There are cheaper surplus example form decommissioned server farms but lets try this one first.

http://www.apc.com/products/resource/include/techspec_index.cfm?base_sku=SURT10000XLT

http://www.ebay.com/itm/APC-Smart-UP...item25a9c38ea8

I'm not going to go find the datasheet for that specific model. But I am very familiar with the UPS units typically found in datacenters and no, they generally do not support split phase operation.

[tehan]

Tehan, despite being unable to know everything you have written and certainly not everything you are thinking, I do think that I'm in general agreement with most everything you have said here with the exceptions including this point you appear to be making.

If you look at the context of my statement I had divided the possibility of GTI operation for islanding into two classes 1.) GTI without output voltage operation on a single set of lines operating in either Island or non-island modes and #2) GTI operation on a separate output with voltage regulation. The point being that GTI operation on the primary outputs is always not output voltage regulated. So for output voltage regulation you would necessarily need to have a new set of dedicated outputs for Island Mode from a GTI. You could call the GTI with "added hardware" the new output but it has to be distinctly different to the floating GTI outputs.

The relevance of this characterization is that to meet NEC safety requirements for mutual exclusion with POCO power, the only approved method (and I dare say I can't think of another) other than a transfer switch is a default mode to shut off when line voltage drops. So you either find #1) an approved way to use the GTI inverter the way it is without output voltage regulation or #2 you create a separate capability.

From within these two classes split phase operation is a member of the class as well as SB SPS. BTW, I have described a means of doing split phase using two SB SPS with UPS powering a 240 panel for 120 loads. The two phases are total isolated and independent with separate voltage regulation provided by SPS and surge capability provided by the UPS. Is it possible, I think so. Is it practical only with a whole house transfer switch, is it likely? Probably not as it only uses a portion of the total PV output, puts an unorthodox set of line voltages on the panel and is not worth the effort is it is just as easy to get the whole enchilada.

Which gets back to the other thing that comes to mind that your wrote and I disagree with; a separate set of outputs from a GTI for islanding (case #2) is not likely despite the comments above but for the same reasons that you have explained. The GTI does not do output voltage regulation for single phase or split phase!! So if it needs to do it it has to be added. But that is not all that is needed namely, surge capacity (so sort of battery/charging system) as well as the probable utility of integrating a gen set as well and the need for safety interlock. So the GTI is missing too much to think it can do more by adding more stuff into it. It would be far cheaper to use it "as is" as a floating voltage power convertor and accommodate the other functionality outside.


BTW one other thing we can agree on is that your backhanded comments about Sunking are in the vein you suggested.

I'm not going to respond to all the points in your long-winded and boring post. But most everything you say is wrong. And look, don't take my word for it. Go research the product roadmaps for Fronius and SolarEdge, both of whom have announced and publicly demonstrated GTI models with off-grid capability. In both cases, these products are based on modest adaptations to their existing GTI designs, not on the absurd UPS scheme you have suggested. There are many reasons this approach is superior: some economic, some safety-related, and some related to desirable product capabilities. But I really have no interest in debating any of this with you while you continue to have your "dickishness" level set to 11.

[posplayr]

You are mistaken. Most 240V UPS systems do not support split phase operation. Yes, there are systems available that include an autotransformer but they are kind of expensive which was sort of my point.

Are you saying this double conversion 240V UPS will not handle a typical household load imbalance? There are cheaper surplus example form decommissioned server farms but lets try this one first.

http://www.apc.com/products/resource/include/techspec_index.cfm?base_sku=SURT10000XLT

http://www.ebay.com/itm/APC-Smart-UPS-RT-SURT10000XLT-10kVA-8kW-Single-Phase-200-240V-AC-6U-Rack-Mount-/161761955496?hash=item25a9c38ea8

[posplayr]

A major limitation of SPS is that it does not support split phase operation, precisely the issue that I had raised. So no, it is not an example of a solution to this problem that already exists.



You are mistaken. Most 240V UPS systems do not support split phase operation. Yes, there are systems available that include an autotransformer but they are kind of expensive which was sort of my point.

The "dickishness" comment was indeed childish, but it was truly meant as a helpful suggestion rather than an insult. You are of course free to ignore it. There was sort of a "dickishness" vacuum here after SunKing left so I guess someone has to fill it

Tehan, despite being unable to know everything you have written and certainly not everything you are thinking, I do think that I'm in general agreement with most everything you have said here with the exceptions including this point you appear to be making.

If you look at the context of my statement I had divided the possibility of GTI operation for islanding into two classes 1.) GTI without output voltage operation on a single set of lines operating in either Island or non-island modes and #2) GTI operation on a separate output with voltage regulation. The point being that GTI operation on the primary outputs is always not output voltage regulated. So for output voltage regulation you would necessarily need to have a new set of dedicated outputs for Island Mode from a GTI. You could call the GTI with "added hardware" the new output but it has to be distinctly different to the floating GTI outputs.

The relevance of this characterization is that to meet NEC safety requirements for mutual exclusion with POCO power, the only approved method (and I dare say I can't think of another) other than a transfer switch is a default mode to shut off when line voltage drops. So you either find #1) an approved way to use the GTI inverter the way it is without output voltage regulation or #2 you create a separate capability.

From within these two classes split phase operation is a member of the class as well as SB SPS. BTW, I have described a means of doing split phase using two SB SPS with UPS powering a 240 panel for 120 loads. The two phases are total isolated and independent with separate voltage regulation provided by SPS and surge capability provided by the UPS. Is it possible, I think so. Is it practical only with a whole house transfer switch, is it likely? Probably not as it only uses a portion of the total PV output, puts an unorthodox set of line voltages on the panel and is not worth the effort is it is just as easy to get the whole enchilada.

Which gets back to the other thing that comes to mind that your wrote and I disagree with; a separate set of outputs from a GTI for islanding (case #2) is not likely despite the comments above but for the same reasons that you have explained. The GTI does not do output voltage regulation for single phase or split phase!! So if it needs to do it it has to be added. But that is not all that is needed namely, surge capacity (so sort of battery/charging system) as well as the probable utility of integrating a gen set as well and the need for safety interlock. So the GTI is missing too much to think it can do more by adding more stuff into it. It would be far cheaper to use it "as is" as a floating voltage power convertor and accommodate the other functionality outside.


BTW one other thing we can agree on is that your backhanded comments about Sunking are in the vein you suggested.

[ButchDeal]

So it raises the question is the Tesla Battery anything else but an oversized UPS? Apparently they see them as linked and perhaps in the way being described.

The Tesla Powerwall battery is not a UPS. it is nothing more than a battery. To use it you need an inverter like the SolarEdge inverter.
SolarEdge has two modes of using a battery. Both have a replacement section at the bottom with the DC attachment and disconnects.
It will be initially available only on the SE7600 model and supposedly with upgrade capabilities for existing SE7600s. The new lower section has an additional DC connection point for the battery, and an additional AC connection for the emergency (backup) circuit panel.
To use it for backup capability an auto transformer is required.

[sensij]

I sort of figured one of you guys who has installed a bunch of whole home backup systems would say that. So yeah, I certainly accept that the line interactive UPS do exist. But they are more complex, US only, and sort of distinct from the volume economies of the datacenter/telecom market so I stand by the "more expensive" part of my comment.

Must go hunt down SK - have been missing him!

If the point of most of this thread was to develop support for the idea that a UPS based architecture with a standard grid-tie inverter would be less expensive than a proper hybrid system, the "more expensive" comment with respect to a high power split-phase UPS seems important. Certainly, the UPS used as an example in this post doesn't meet the split phase requirement (and I'm not even finding that model on ebay for the $2000 suggested).

Perhaps if posplayr produced an updated drawing showing his idea as it has been refined by the discussion since it was originally posted, it would be easier to evaluate against the existing methods of providing grid-down power that others have suggested. At this point, I am not convinced there is anything here that is more cost-effective than a standard hybrid system, but the technical discussion has been been interesting, even if plagued by misunderstandings and inaccuracies (my own posts not excluded).

[inetdog]

Must go hunt down SK - have been missing him!

Warning: Do not stick your head inside the Lion cage! It annoys the lion and is unsafe to boot.

[tehan]

Yes, the SPS is 120V only.
I would take issue with your statement about UPS systems, especially those for the US market. You can get a UPS that is designed for a 240V line to line only load, but you can also get them for split phase (120/240) operation. Those do not necessarily incorporate an autotransformer, but they do need two separately driven 120V output stages.

FYI SK is back and seems to be on his best behavior, namely reasonably polite but still firm with people who are clueless and reject good advice.

I sort of figured one of you guys who has installed a bunch of whole home backup systems would say that. So yeah, I certainly accept that the line interactive UPS do exist. But they are more complex, US only, and sort of distinct from the volume economies of the datacenter/telecom market so I stand by the "more expensive" part of my comment.

Must go hunt down SK - have been missing him!