If an ATS separates an existing grid-tie inverters from a new off-grid system, can the same solar panels be used with both inverters?

[summit]

I have an inverter from MPPsolar, the user manuals look so much alike.

 

[wattmatters]

I have an MPP hybrid-inverter, and SunGold's manual looks just like MPP's

all the clones do

 

[Not Aerosmith]

Who is their local support in Australia? Never heard of them. Website mentions nothing other than they've sold to customers here but no mention of local support. None of their inverters are suitable/designed for our electrical system.

They look like a clone manufacturer.

I repeated wattmatters search. I even used NordVPN to set my location to Australia. I had hope that SunGoldPower website would link me to Australia, but no back to USA. My search results were the same as wattmatters.

I'm not affiliated with SunGoldPower, so I can't speak for them. My search did indicate that SunGoldPower have 50 products beside inverters, so maybe they have sales and support on another product in Australia. I honestly don't know.

 

[Not Aerosmith]

Right now from all the research, I'm second guessing both the MPP Solar LVX6048WP and the SunGoldPower IP6048. Both of these inverter require a 40 amp breaker between the grid and the inverter, so that they can be service. My existing 15 KW grid tie inverter is connected to the grid with an 80 amp breaker. I really can't take my existing (3) 5 KW inverters through either of these hybrid inverters that are protected with a 40 amp breaker.

I assume that why they can parallel up to 6 inverters in order to match up to a 240 amp service. I would need to buy 3 inverters ($6K) and 30 KWH of batteries ($12K) to make a hybrid system work with the existing 15 KW grid-tie system. Since 2/3 of my production goes to the grid, I would need to spend $18K in materials plus miscellaneous materials and installation cost to use either of these system.

It seems that my best option is to use the new 15KW Sol-Ark hybrid inverter ($8K), since it can be installed without any batteries and AC couple my existing 15 KW Fronius grid-tie inverters. In a few month, I could add (5) 5 KWH batteries ($10K). Since the Sol-Ark is all-in-one with disconnects, there should be less miscellaneous material and cheaper installation cost. The inverter also has a 10 year warranty.

 

[Ampster]

It seems that my best option is to use the new 15KW Sol-Ark hybrid inverter ($8K), since it can be installed without any batteries and AC couple my existing 15 KW Fronius grid-tie inverters.

That sounds like a good plan. I don't think any hybrid is going to AC couple very successfully without batteries or a fairly consistent load. In the meantime, until you get batteries, you could just switch off some of your GT inverters when you do have a power outage and you want to use some solar. The more consistent loads you have in that scenerio the less buffering the grid forming inverter has to do as loads change. The batteries do the buffering that the grid typically does when the grid is up. The SolArk does use the generator port so it can quickly disconnect the AC coupled GT inverters if frequency Watt cannot get them to ramp down quickly enough/

 

[Nobodybusiness]

Besides Schneider/Outback/SolArk/SMA (high cost), which hybrid/all-in-one can even turn on GT ? let alone AC coupling ?

Just regular cost. You get what you pay for..
I can go with pricey as a description.

 

[summit]

I am curious to find out if the Fronius can be AC-coupled. Heard in the past that it's difficult with Fronius GT.
~$20K is too pricey for me

here's MPP email response to my inquiry about Sungold: " Sungold power is one of our OEM brands. . a company owned by the Chinese and has a company also in the US."
I am doubtful whether these cheapies can do grid-tie function, and surely not "approved"

 

[wattmatters]

I am curious to find out if the Fronius can be AC-coupled.

Fronius are grid following inverters. They can be controlled by a grid forming inverters using AC frequency control.

This is how they work with Tesla Powerwall 2's inverter when operating in grid outage mode, and micro-grid forming inverters such as the Selectronic can take control of a Fronius, adjusting the micro-grid frequency so as to control the output from the Fronius.

As with all such things, it requires careful design - there is a limit on the size of inverter capacity which can be controlled in this manner - it shouldn't be greater than the ability of the off/micro-grid system's capacity to manage a dump load, e.g. the instant should the grid goes offline while the grid tied PV system is cranking out full power under the Summer sun.

 

[Not Aerosmith]

Fronius are grid following inverters. They can be controlled by a grid forming inverters using AC frequency control.

This is how they work with Tesla Powerwall 2's inverter when operating in grid outage mode, and micro-grid forming inverters such as the Selectronic can take control of a Fronius, adjusting the micro-grid frequency so as to control the output from the Fronius.

As with all such things, it requires careful design - there is a limit on the size of inverter capacity which can be controlled in this manner - it shouldn't be greater than the ability of the off/micro-grid system's capacity to manage a dump load, e.g. the instant should the grid goes offline while the grid tied PV system is cranking out full power under the Summer sun.

Excellent question that I need to ask before buying the new Sol-Ark 15 KW SA-Limitless hybrid inverter. Modulating the 15 KW grid-tie inverters output is only needed when the grid is down, because I need to maximize the grid-tie inverters output when the grid is up and store about 2/3 of production on the grid to be use later.

There is one person on DIY that has already installed this new hybrid inverter to use while he is building his house. He has indicated that it sometimes has problems powering the construction equipment and Sol-Ark solution was to add an autotransformer. He concern how it will do powering his whole house when construction is completed. Most DIY reviews comments are about the seemly misleading naming of the Sol-Ark inverters. This new Sol-Ark 15 KW SA-Limitless hybrid inverter is 15 KW power as named with PV at 19.5 KW. What really sold me was the 200 amp pass through, AC coupling and listed as a whole house solution.

I really do appreciate your input, guidance and help. Thanks, Steven Tyler

 

[Not Aerosmith]

Fronius are grid following inverters. They can be controlled by a grid forming inverters using AC frequency control.

This is how they work with Tesla Powerwall 2's inverter when operating in grid outage mode, and micro-grid forming inverters such as the Selectronic can take control of a Fronius, adjusting the micro-grid frequency so as to control the output from the Fronius.

As with all such things, it requires careful design - there is a limit on the size of inverter capacity which can be controlled in this manner - it shouldn't be greater than the ability of the off/micro-grid system's capacity to manage a dump load, e.g. the instant should the grid goes offline while the grid tied PV system is cranking out full power under the Summer sun.

I am curious to find out if the Fronius can be AC-coupled. Heard in the past that it's difficult with Fronius GT.
~$20K is too pricey for me

here's MPP email response to my inquiry about Sungold: " Sungold power is one of our OEM brands. . a company owned by the Chinese and has a company also in the US."
I am doubtful whether these cheapies can do grid-tie function, and surely not "approved"

SunGoldPower IP6048 are UL 1741 listed and listed as AC coupling hybrid inverter. My problem is they require a 40 amp breaker between the inverter and the grid and the description was clear that the grid-tie inverters can feed the batteries when the grid is down. I would assume that if I'm only trying to send 15 KW to the grid, which is about 65 amps that two of these hybrid inverters in parallel might work assuming 80% breaker capacity. As an engineer, I would want (3) inverters as a minimum. I could buy (2) Blue Power IP6048 with (4) 5 KWH SOK batteries now and in a few month add another inverter with (2) 5KWH SOK batteries. The initial cost is either $8K for Sol-Ark or $12K for SunPower. Total cost for both systems is about $18K plus shipping, miscellaneous parts and installation. My gut feeling is that, if I going to spend $12K that the better solution is Sol-Ark with (2) 5 KWH SOK batteries.

 

[wattmatters]

Excellent question that I need to ask before buying the new Sol-Ark 15 KW SA-Limitless hybrid inverter. Modulating the 15 KW grid-tie inverters output is only needed when the grid is down, because I need to maximize the grid-tie inverters output when the grid is up and store about 2/3 of production on the grid to be use later.

As an example, for Powerwall 2 installations in Australia, when set up to operate in grid outage mode and take control of the GT inverter, the GT inverter cannot have an output capacity greater than 7 kW. That's because the Powerwall has a max surge absorption capacity of 7 kW, which buys it enough time to get the GT inverter's output under control. It cannot be coupled with a GT inverter with higher rated output.

If the battery it at/near full, then the PW's inverter will immediate raise the micro-grid frequency to about 5-6Hz above the regular grid signal frequency, and that's sufficient to shut down the GT inverter temporarily. As the Powerwall's battery is discharged its inverter begins to reduce the frequency of the micro-grid and eventually the GT inverter will start to operate and generate output, but throttled according to how far above the standard frequency the grid signal is.

Hence for homes with larger solar PV systems, Tesla advise having more than one GT inverter, and having the Powerwall control one inverter, typically a 5 kW unit with up to 6.66 kW of PV but you could have a 6 kW inverter. This keeps it nicely within the spec of the Powerwall's capacity to manage a dump load.

That means only that one inverter and its PV array remain online during grid outages but for essential load support during grid outages it's usually enough to keep things running (normally the system is set to supply power to selected circuits only during outages). The rest of the GT PV system remains off-line. You can of course add more batteries to enable the rest of the PV system to also operate.

 

[Not Aerosmith]

As an example, for Powerwall 2 installations in Australia, when set up to operate in grid outage mode and take control of the GT inverter, the GT inverter cannot have an output capacity greater than 7 kW. That's because the Powerwall has a max surge absorption capacity of 7 kW, which buys it enough time to get the GT inverter's output under control. It cannot be coupled with a GT inverter with higher rated output.

If the battery it at/near full, then the PW's inverter will immediate raise the micro-grid frequency to about 5-6Hz above the regular grid signal frequency, and that's sufficient to shut down the GT inverter temporarily. As the Powerwall's battery is discharged its inverter begins to reduce the frequency of the micro-grid and eventually the GT inverter will start to operate and generate output, but throttled according to how far above the standard frequency the grid signal is.

Hence for homes with larger solar PV systems, Tesla advise having more than one GT inverter, and having the Powerwall control one inverter, typically a 5 kW unit with up to 6.66 kW of PV but you could have a 6 kW inverter. This keeps it nicely within the spec of the Powerwall's capacity to manage a dump load.

That means only that one inverter and its PV array remain online during grid outages but for essential load support during grid outages it's usually enough to keep things running (normally the system is set to supply power to selected circuits only during outages). The rest of the GT PV system remains off-line. You can of course add more batteries to enable the rest of the PV system to also operate.

After reading your quote, I'm thinking that maybe my best option is to replace one of the 5 KW Fronius Primo inverter with the new Sol-Ark 15 KW hybrid inverter. It seem like it would be simpler to swap an existing Fronius inverter for a the new Sol-Ark hybrid inverter versus doing a complete new inverter installation.

I believe that there are several advantages: 1. Swapping a new inverter for an existing inverter should be a simpler installation. 2. The new hybrid inverter would have 6 KW of solar panels to try and satisfy the load before need to activate the (2) remaining grid-tie inverters. 3. The new 15 KW hybrid inverter now only need to control (2) 5 KW on-grid inverters versus (3) 5 KW inverters. 4. If an inverter should stop working, I have a replacement inverter that could be installed immediately and quickly. 5. The new hybrid inverter will let me add up to another 13 KW of solar panels, which is something that I intend to do. 6. My equipment utility area is getting crowded, so swapping inverters will take less space. 7. If the new Sol-Ark 15 KW hybrid inverter has too many design issues, it would be easier to change back to the original installation.

Any suggestions???

 

[summit]

trying to AC coupling a 15kw system is a very tall order, while it may seem convenient to avoid having a separate critical load panel; but a hefty transfer switch is also needed upon islanding. The other design parameter to consider is how often and how long are the outages ? which are different for different local region.

 

[Not Aerosmith]

trying to AC coupling a 15kw system is a very tall order, while it may seem convenient to avoid having a separate critical load panel; but a hefty transfer switch is also needed upon islanding. The other design parameter to consider is how often and how long are the outages ? which are different for different local region.

To justify my actions, I do have 5 electrical panels plus the panel for the inverters. Usually a critical load panel is installed next to the house panel and you simply move circuits to the new critical load. Simple task for most, but not for someone with 5 electrical panels that are scattered all over the house. The Sol-Ark Limitless 15 KW hybrid inverter is advertised with an AC couple solution. However, I'm anxious to buy, but want to do my due diligence and make that it will work with the (3) 5 KW grid-tie Fronius inverters. Hopefully, if I substitute the Sol-Ark hybrid inverter for one of the GT inverter, I then have 6 KW of solar panels that will normally satisfy the load most of the time and only need AC couple to control the remaining two GT inverters.

I do intend to verify with Sol-Ark before buying, but odds are their answer is usually NO PROBLEM before the purchase. After the Sol-Ark purchase, support will provide inadequate work around solutions to AC couple the GT inverters. Probably with an end goal of making me give up and finally replace the two GT inverters with another Sol-Ark. Of course, the second Sol-Ark won't really help without batteries, so they will send me somewhere to buy at least 400 amp in batteries. Probably will be totally frustrated a partial hybrid solution and out $17K in Sol-Ark and $10K in batteries plus shipping, miscellaneous parts and installation.

My original intent when I installed the (3) 5 KW GT inverters plus 57 solar panels and to replace the Fronius inverters in 5 years when the warranty had ended. I figured in 5 years that the hybrid inverters would have whole house backup solutions versus critical load panel solutions that I was offered 3 years ago. To be honest, I think the inverter market still need another 2 years to provide viable and reliable house house backup solutions to convert existing GT systems to hybrid systems.

Patience is not one of my virtues and I'm too anxious to do something instead of waiting the 5 years per my original plan.

 

[Not Aerosmith]

Someone suggested the Gen 24 hybrid inverter by Fronius. I have not been able to find one online for split phase 115/230 volts. I'm sure that in the next 2 years it should be available in split phase with the inverter functions already well tested in Europe and Australia. This inverter is being marketed as a whole house solution instead of a critical load panel solution, which check most of my boxes for what I want. Probably the biggest advantage is that the communication protocol between the new Fronius hybrid inverter and the existing Fronius GT inverters should work flawlessly with no control issues.

 

[summit]

has any done/heard that Fronius GT been successfully AC-coupled ? when I looked into this ~10-yrs ago, I was told that they couldn't get the Fronius to turn on. I would confirm, though not sure how, that the Sol-Ark will turn the Fronius on before pulling the trigge

One of your other thread indicates you're in Panama, the grid may be more forgiving there to allow cheap hybrid inverter to grid-tie, as opposed to being in the States.

Wattmatters raised a good point about dump-loading, during AC-coupling generating more than demand. Given that the field is changing rapidly, small baby step is warranted rather than a leap. I am eagerly waiting for Vehicle-2-House configuration

 

[Ampster]

Any suggestions???

Replacing one of the Fronius inverters sounds like a good plan for the reasons you articulated. The easiest way to determine if the remaining Fronius can be controlled by the SolArk is to see if they comply with UL1741?

 

[Not Aerosmith]

Replacing one of the Fronius inverters sounds like a good plan for the reasons you articulated. The easiest way to determine if the remaining Fronius can be controlled by the SolArk is to see if they comply with UL1741?

I just check the original Fronius proposal from 3 years ago to make sure that the Fronius installed were UL1741.

The Fronius Data sheet included with the proposal shows "Certificates and compliance with standards: UL1741-2015, UL1998 (for functions: AFCI, RCMU and isolation monitoring), IEEE 1547-2003, IEEE 1547.1-2003, ANSI/IWWW C62.41, FCC Part 15 A & B, NEC 2014 Article 690, C22.2 No 107.1-01 (September 2001), UL1699B Issue 2-2013, CSA TIL M-07 Issue 1-2013."

Fronius is made in Europe not Asia, which for me is a good thing. So far, they haven't given me any trouble in over 3 years. Fronius has release a new 6 KW hybrid inverter for whole house backup: Fronius Primo Gen 24. So far, I haven't found where it is available for split phase 120/240 installation.

 

[Ampster]

The Fronius Data sheet included with the proposal shows "Certificates and compliance with standards: UL1741-2015,

That should work. It will respond to frequency Watt by going off line then come back if the load is increased. Only the newer 1741SA will modulate but that is another reason to put panels on the new hybrid. DC coupled panels on a hybrid respond faster and will modulate. That will be a good balance of functionality.

 

[Not Aerosmith]

That should work. It will respond to frequency Watt by going off line then come back if the load is increased. Only the newer 1741SA will modulate but that is another reason to put panels on the new hybrid. DC coupled panels on a hybrid respond faster and will modulate. That will be a good balance of functionality.

Thanks for sharing your knowledge on UL1741 and UL1741SA. It is really helpful and encouraging that my existing (3) Fronius Primo 5 KW GT inverters can interface with a new hybrid inverter. Hopefully, I'm evolving and becoming more knowledgeable thanks to the DIY Forum.

I was seriously considering the MPP Solar LVX6048WP or the SunGoldPower IP6048 hybrid inverters, but learned that those hybrid inverters install between the house and grid with an ATS and need a 40 amp breaker according to the owner manual. Obviously 40 amps is inadequate for a house, so you need to parallel several hybrid inverters to get the amperage needed for the house plus you need (2) 5 KWH batteries for every hybrid inverter that you parallel. Not really the inexpensive whole house solution promised, if you need at least (3) inverters ($6K) and (6) batteries ($12K) plus miscellaneous components and the installation cost. I'm sure these are both excellent inverters for some, but they are not a good fit for my situation.

I was seriously considering the Sol-Ark Limitless 15 KW hybrid inverter ($8K), because it is an all-in-one inverter with a 200 amp breaker for a whole house solution. I have only seen performance videos on the previous Sol-Ark inverters models and they seem to have a history of nuisance trips for unbalanced loads and frequently unable to start motors. Furthermore, testing has demonstrated that the Sol-Ark are not able to perform per their actual rating not talking about their implied ratings by misleading model names. Maybe the new hybrid inverter will have fixed all the problems listed in the DIY Forum posts and YouTube videos, I don't know. Not willing to gamble $8K to find out.

I have flawless performance from my (3) 5 KW Fronius Primo GT inverters, so I decided to look at the new Fronius Primo Gen 24 hybrid inverter, which is also listed as a whole house solution and been in production for over 2 years. Reviews seem excellent and price is reasonable, but not yet available in a split phase 115/230 volts power option as needed for USA or in my case, Panama.

Now I have decided to buy a Schneider XW Pro 6.8 KW hybrid inverter and add batteries. Originally, I thought these couldn't be installed in parallel and they were not an all-in-one solution. I assumed their were better options. After exploring many of those other options, I found out that I was wrong about many things. The Schneider XW Pro 6.8 KW hybrid inverter can be parallel and it is probably the best option for me. There are advantages to not being an all-in-one inverter. If a component stop working, you only need to replace what not working not the whole all-in-one inverter. I also saw several videos on testing the Schneider and they exceeded their name plate ratings and started a compressor while in overload. In several videos it was shown that they don't have an issue with unbalanced loads or starting motors, and much more importantly they are not prone to nuisance tripping.

Remember this review is based totally on unsubstantiated Internet searches, DIY post, YouTube videos, etc. I have no personal experience with any inverters mentioned other than Fronius Primo GT inverters. I'm sure that all the inverters mentioned work excellent for some people, but they don't seem to be my best option. If my comments were inaccurate or offended anyone, I'm sorry and please accept my apologies. My intentions are only to share knowledge, which so many of you have done for me. Special thanks to wattmatters and Ampster. I really appreciate all the past comments and guidance helping me to make a more informed decision. Thank you, Steven Tyler (Not Aerosmith)