Can Growatt Inverter do this?

RememberTheMagic

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I can run my whole home with the 12K Grid tied and my bill was really high as Irun a salt water aquarium is alone consuming about 20KWh per day. I have 16KWh of batteries and 10.4Kw of Panels hooked up to the Sol-Ark. If I had 30KWh of batteries like you I would have probably gone off grid.

It's a thing of beauty to watch the Sol-Ark in action, it uses just PV as long as the sun is shinning, if clouds come over it will use the batteries along with the lower PV output to jointly power the house. When the clouds pass it will use the excess PV power to charge back the batteries first and then sell to the grid second (if that option is selected). If the power goes down it will transfer to Solar/Batteries within 4ms so its almost impossible to tell when there is an outage. The only way I know is that the phone App sends me a push notification.

At night I can schedule battery usage times and the max KW it can draw during each period, anything over that max and it will supplement it with grid power. So if by chance three compressors kick on at the same time and it needs more than the 2.5KW that I set and lets say it needs 4.5KW it will draw 2KW from the grid for as long as needed. You can also set it to Grid charge the batteries during certain periods or if the batteries reach down to a certain level. During a power outage the limitations in scheduling will be bypassed and it will use what you set as the maximum draw from the batteries as the limit. If for some reason the unit trips and I have only had this happen once when I was testing the limits, the unit will reset itself in a minute and go back to normal operation.


I am still using Grid power for about five hours in the evening using the scheduling feature but the remaining 20% of the bill is reducing rapidly as we change a few of our habits to get more things done in the daytime. If for some reason you need more power I understand that Sol-Ark will be releasing a 15K unit in a couple of months. I don't really agree with some of the posts saying to get a low freq inverter with a big transformer. Yes they are really good at starting heavy loads but they are also very inefficient when compared to transformless models.

I am an EE and designed the wiring and layout plus installed most of my system myself. I am not into DIY solar as a hobby as I have lots of hobbies already. What I needed was reliable power and just wanted a system that is straight forward yet extremely customizable.
Sol-Ark pretty much ticked all the right boxes for me.
I talked to a Sol-ARK vendor and they are unsure if the SOL-ARK has the ability to power the loads from the battery on a schedule (I.e. set loads to get power from Batteries only from 2am-7am). Do you happen to know?
 

RememberTheMagic

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For a grid tied system it would look something like this:

View attachment 66609

In this arrangement the inverter will keep taking whatever power the SCC gives it and pump it into the breaker box. From there the energy will go to the Loads, and if there is any excess it will backfeed the grid.

For a hybrid system (no back feed) it will typically look like this:
View attachment 66612

In this arrangement, the inverter will take power from the grid to power the critical loads or charge the battery, but it will never pump power back onto the grid. There are many different configurations with where the inverter decides to get power to drive the critical load (Battery or grid). However, no matter what the configuration is, if the SCC decides the system does not need power, it shuts off the current through the solar panel and no power is generated.
So in the case of the GTIL example, you gave above., It seems to be that this is the most cost-efficient model in that you get the benefits of the grid for supplemental power (surges, night, etc.), easy one breaker installation, etc. The cons' are loss of utility power = bad day and no power for the panel in spite of the fact you are still producing PV power and batteries are fully charged?

So no one makes a GTIL that has a built in transfer switch in it that would "disconnect" the utility power in the event of an outage and run the whole house off the PV/Batteries without having to wire in a critical loads panel?

Part of the issue I have is I do not want to go thru the permitting process, trying to avoid that like the plague. I want to power the entire house, supplemented with the utility power and take my chances when/if power goes down. Worse case I can flip off the main breaker that feeds all the loads in the house and crank up a generator to "replace" the utility power.
 

FilterGuy

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So no one makes a GTIL that has a built in transfer switch in it that would "disconnect" the utility power in the event of an outage and run the whole house off the PV/Batteries without having to wire in a critical loads panel?
Not that I am aware of..... but with all the stuff out there, who knows what might be available.

I would like to do the same as you:. Be able to drive the whole house from my solar & battery but still have utility back-up. The easiest way to do this is to put the grid power through a hybrid and drive the house from the hybrid output. The problem I have is that my main breaker panel is tied with the utility meter box in a way that there is no good way to intercept between the meter and the main breaker. That means I have to either replace the main breaker & Meter panel or wire a 2nd breaker panel. Both options are a huge PITA.
 

RememberTheMagic

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Not that I am aware of..... but with all the stuff out there, who knows what might be available.

I would like to do the same as you:. Be able to drive the whole house from my solar & battery but still have utility back-up. The easiest way to do this is to put the grid power through a hybrid and drive the house from the hybrid output. The problem I have is that my main breaker panel is tied with the utility meter box in a way that there is no good way to intercept between the meter and the main breaker. That means I have to either replace the main breaker & Meter panel or wire a 2nd breaker panel. Both options are a huge PITA.
Same issue I have.

Surely there is a way to power the loads, get the benefits of the grid when needed all with a simple GTIL.

I know it can be done with a Critical Loads panel but that as you stated is a PITA. I have found many GTIL but few that accept backup as an input that can be combined with the PV AND have the ability to run off batteries as well. I get that a utility outage brings you down completely, but the reality here is that happens about once every 5 years for a day. Even then I have a generator that could be brought online (with the meter either pulled or the main breaker OFF).
 

fafrd

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Exactly what I am looking for. What GTIL did you end up using? I also want the battery to be able to feed the GTIL so we get the most out of the solar panels (ie. power the loads and use excess power to charge the batteries, when solar is gone start using the batteries.). I think of the batteries as a solar storage device, where the PV panels are the main source to power the GTIL and the batteries are there as a backup to the PV Panels as another input into the GTIL
Prices keep inching up (I got mine for $250 early this year): https://www.amazon.com/Inverter-Lim...ocphy=9032083&hvtargid=pla-523294429130&psc=1

Finding correct documentation online is difficult and you find will some places that state that these will not work with 24V batteries (and suggest 36V batteries are the minimum).

I bought from Amazon so I could return if they did not perform to my expectation but they they ran fine off of a 24V battery (22V is the minimum input voltage before the inverter shuts down for low voltage disconnect).

I would have gone with a 48V battery but wanted a 1S PV string to deal with shading issues (combined with half-cut panels).

If running off of a 24V battery, you just need to size cables to minimize voltage drop at peak current (I used 2/0 welder’s cable from battery to each inverter, so only about 1mOhm total from terminals to each inverter and dropping less than 50mV even at peak drain of ~40A).
 

fafrd

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Not that I am aware of..... but with all the stuff out there, who knows what might be available.

I would like to do the same as you:. Be able to drive the whole house from my solar & battery but still have utility back-up. The easiest way to do this is to put the grid power through a hybrid and drive the house from the hybrid output. The problem I have is that my main breaker panel is tied with the utility meter box in a way that there is no good way to intercept between the meter and the main breaker. That means I have to either replace the main breaker & Meter panel or wire a 2nd breaker panel. Both options are a huge PITA.
This was exactly my situation (and the rewiring cost/complexity is exactly why I decided to ditch the beautiful hybrid design I was planning in favor or trying these GTILs.

GTILs will never provide a backup solution, since they are grid-tied and require the grid signal to come from the grid (externally).

I’ve rigged up a 3kW PSW that I can activate manually when the grid goes down (primarily for our rare multi-day pre-planned power outages for fire prevention). The PSW will wake up the GTILs but since they won’t see and grid power, they won’t produce anything (though in principle, it should be possible to move the sensors to the PSW output wires if I even need a ‘boost’ above 3kW).

I’m comfortable this rig will be sufficient for the next few years but it doesn’t power any 240V loads, so I may eventually move to a split-phase PSW to get the full house wiring up and running during an outage (though honestly, it’s unlikely we’re ever going to NEED to make a soufflé during a power outage ;).

As with any PSW-based backup solution, I’ll need to manually disconnect from the grid (open the main breaker) before closing the ‘off-grid’ breaker and firing up the PSW.

An automatic transfer switch would be nice but opens up the exact same can of worms as it would need to be positioned between the main breaker and the main panel (which are back-to-back in my case: main breaker outside and main panel inside on the opposite side of the same wall, so wire just running through a 4”-long piece of conduit).
 

robby

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I talked to a Sol-ARK vendor and they are unsure if the SOL-ARK has the ability to power the loads from the battery on a schedule (I.e. set loads to get power from Batteries only from 2am-7am). Do you happen to know?
Yes it can absolutely do that. You set the time and then the SOC and it will only use the battery if the SOC is above that number. I do not have TOU charges from my utility and I also have a generator but would rather not run it late at night if there is a blackout. So mine is setup to use batteries at 11pm all the way back until 5am-7am.

In the day so long as the battery SOC is above 35% it will use up to 2KW-2.5KW to supplement the solar if its cloudy.

Basically the data fields are something like this

Time --- Max Power--- SOC------ (Explanation)
01:00--- 2500W---- 20%------ So as long as the batteries are above 20% SOC it will draw up to 2.5Kw of power at 1am until 5am anything above 2.5Kw of load and the extra will be drawn from the Grid.

05:00--- 2200W---- 20%------- Batteries are still in use but can now only provide 2.2Kw max until 20% SOC is reached.

---Typically by 5:30 to 6am the batteries are at 20% SOC and I am now on Grid until 7:30am ----

09:00----2000W---- 35%------- Assuming batteries have charged back past 35% SOC by 9am it will use 2Kw to supplement Solar if needed.

--- By 11am my batteries are typically at 100% SOC ---

12:00----2500W---- 90%------- It will use up to 2500W to supplement PV as needed so long as the batteries have reached above 90% SOC. If it's cloudy it will draw power, if sunny it charges the batteries and then sell back is optional. On a typical day it will do a few of these disharge and charge cycles to stay off the grid. Typically the batteries are at around 97% SOC by 5pm.

17:00----2000W---- 100% -------100% means do not use the batteries, so after 5pm it will not use the batteries, most remaining PV power is now diverted to charging the batteries back to 100% and I am on the grid until 11pm

23:00----2500W----- 20%-------- It starts the Night cycle at 11pm using a max of 2.5Kw draw until SOC reaches 20% This continues until after 5am when at some point between 5am and 6am the batteries drop to 20% SOC and then it's on the Grid for a short period until maybe 7:30am when PV output is enough to power the loads fully.

Every parameter is changeable. With your 30KW battery system (assuming it's LifePO4) I would up those numbers into the 5-6KW range and go from 5pm till 7am on battery.
In the day my house is running at about 6-8Kw of consumption during the peak hours. We keep the AC's running a bit colder in the day so cooling at night consumes less power and we do all the washing and drying of clothes during that time plus run the water heater.
 
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RememberTheMagic

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Yes it can absolutely do that. You set the time and then the SOC and it will only use the battery if the SOC is above that number. I do not have TOU charges from my utility and I also have a generator but would rather not run it late at night if there is a blackout. So mine is setup to use batteries at 11pm all the way back until 5am-7am.

In the day so long as the battery SOC is above 35% it will use up to 2KW-2.5KW to supplement the solar if its cloudy.

Basically the data fields are something like this

Time --- Max Power--- SOC------ (Explanation)
01:00--- 2500W---- 20%------ So as long as the batteries are above 20% SOC it will draw up to 2.5Kw of power at 1am until 5am anything above 2.5Kw of load and the extra will be drawn from the Grid.

05:00--- 2200W---- 20%------- Batteries are still in use but can now only provide 2.2Kw max until 20% SOC is reached.

---Typically by 5:30 to 6am the batteries are at 20% SOC and I am now on Grid until 7:30am ----

09:00----2000W---- 35%------- Assuming batteries have charged back past 35% SOC by 9am it will use 2Kw to supplement Solar if needed.

--- By 11am my batteries are typically at 100% SOC ---

12:00----2500W---- 90%------- It will use up to 2500W to supplement PV as needed so long as the batteries have reached above 90% SOC. If it's cloudy it will draw power, if sunny it charges the batteries and then sell back is optional. On a typical day it will do a few of these disharge and charge cycles to stay off the grid. Typically the batteries are at around 97% SOC by 5pm.

17:00----2000W---- 100% -------100% means do not use the batteries, so after 5pm it will not use the batteries, most remaining PV power is now diverted to charging the batteries back to 100% and I am on the grid until 11pm

23:00----2500W----- 20%-------- It starts the Night cycle at 11pm using a max of 2.5Kw draw until SOC reaches 20% This continues until after 5am when at some point between 5am and 6am the batteries drop to 20% SOC and then it's on the Grid for a short period until maybe 7:30am when PV output is enough to power the loads fully.

Every parameter is changeable. With your 30KW battery system (assuming it's LifePO4) I would up those numbers into the 5-6KW range and go from 5pm till 7am on battery.
In the day my house is running at about 6-8Kw of consumption during the peak hours. We keep the AC's running a bit colder in the day so cooling at night consumes less power and we do all the washing and drying of clothes during that time plus run the water heater.

That sounds like what I want. Do you have a schematic of how you wired this up that you don't mind sharing? I am trying to make sure I have my head wrapped around this (fits my needs) before I go drop close to $10,000 on a SCC =o)
 

robby

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That sounds like what I want. Do you have a schematic of how you wired this up that you don't mind sharing? I am trying to make sure I have my head wrapped around this (fits my needs) before I go drop close to $10,000 on a SCC =o)
Sorry but I don't really have a proper schematic as of yet. I kind of made doodles on paper then as each section was being done a lot of it evolved as I realized I could make changes for the better. For instances I did put in a critical loads panel and then realized that Sol-Ark could handle the whole house without an issue, so it's there and wired with breakers in but not in use. I had originally designed the system to be 24 PV panels with three strings of eight but after some more exact measurements came in from the roofing people I realized I could get 28 panels up and instead did 4 strings of 7. I am still in the process of modifications but I wanted a couple of months of operating data to get a better grasp on how I can tweak it further. When it's all finalized I will draw out a propr schematic on my computer so that if anything happens to me my wife will have proper schematics to show the service people.

BTW I think Sol-Ark has some guys at the help desk that can provide some basic layout schematics based on systems in the field. Give them a call.
 

NHRenewables

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Yes this sounds like what I am looking for. It seems in this setup I can (using only one breaker) backfeed the panel in the house and offset utility cost. Any extra power will charge the batteries, then shed pv input to zero (and batteries as well) in the event no loads are on.

I see this as an ideal way to lower power bill but still keep utility power for large loads and inrush current on motors, etc
With AIO (Growatt, MPP), you don’t want to back feed into the main breaker, rather move your critical load to a new sub panel downstream of the AIO. All solar generated via the AIO will be used internally. Bad things will happen if you attempt to close the loop. Follow the electrical code.

You can set SBU priority where:
-You consume solar first,
-Consume battery with solar, and once battery hits low voltage setting.
-Switch over to Utility and consume solar with Utility recharging the battery.
-It will revert back to solar only, when the battery is charged back to the set point.
 

RememberTheMagic

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With AIO (Growatt, MPP), you don’t want to back feed into the main breaker, rather move your critical load to a new sub panel downstream of the AIO. All solar generated via the AIO will be used internally. Bad things will happen if you attempt to close the loop. Follow the electrical code.

You can set SBU priority where:
-You consume solar first,
-Consume battery with solar, and once battery hits low voltage setting.
-Switch over to Utility and consume solar with Utility recharging the battery.
-It will revert back to solar only, when the battery is charged back to the set point.
understood, was trying to use it like a grid tie but from what I read that's never mentioned as an option. Wanted to be Grid Netural yet not have to move all the loads to a separate load panel tied into the output of the inverter.
 

fafrd

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understood, was trying to use it like a grid tie but from what I read that's never mentioned as an option. Wanted to be Grid Netural yet not have to move all the loads to a separate load panel tied into the output of the inverter.
Avoiding the hassle and expense of rewiring a separate load panel is the single biggest advantage of the GTIL architecture (power is supplied in parallel rather than in series).
 

Ampster

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....power is supplied in parallel rather than in series.
Technically the power in the grid and throughout our homes is in parallel. But from the visual of a single line diagram I can see why it appears to be in series.

I agree that just adding a breaker for a GT inverter with a limiter is much simpler than adding a hybrid inverter with batteries and a critical loads panel. With increased complexity comes greater functionality.
 
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fafrd

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Technically the power in the grid and throughout our homes is in parallel.
Precisely.

As I’ve posted in several different places now, these GTILs plug into any 120V socket like any other appliance (such as a toaster). Going for a split-phase rig like I did means being careful that you have one GTIL plugged into each separate phase (which sensors clamped around the same matching phase in the main panel).
But from the visual of a single line diagram I can see why it appears to be in series.
Yes, what I meant is that, while the GTIL architecture allows generated power to be injected ‘anywhere’ (in parallel), the Hybrid architecture requires the ‘series’ connection of grid->inverter->load (and this is the reason connecting a hybrid inverter typically involves rewiring, since direct connection of grid to all loads (in parallel) is the standard home wiring configuration).
I agree that just adding a breaker for a GT inverter with a limiter is much simpler than adding a hybrid inverter with batteries and a critical loads panel.
My GTIL inverters are battery-powered.

The biggest difference between the two architecture is that the Hybrid inverter is inserted directly into the main power path between grid and load. This allows is to only ‘let in’ whatever amount of grid power in needs/wants and also allows it to prevent any power from backfeeding into the grid. That position is also needed in order to provide back-up capability (disconnect from grid and power loads exclusively from battery).

In contrast to a GTIL which will supply some AC power into any outlet just as any appliance would consume some AC power from any outlet.

To prevent export to grid, rather than relying on being in the critical path where it can both control how much power is consumed from grid as well as disconnect from grid when needed (that series connection;)), the GTIL just relies on a clamp sensor placed directly on the grid wire allowing it to continuouslymeasure grid consumption (or export). Using that measured grid consumption allows the GTIL to generate just enough power to drive down consumption from the grid until it can maintain grid consumption just above zero (no export).

The GTIL replaces the power being consumed from the grid with power it is generating from the battery.

It is literally offsetting grid consumption.
 

Ampster

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I would not encourage a configuration that plugs into just "any" outlet. To be safe that outlet needs to be on a dedicated breaker. I believe that is consistent with the building code. That being said, it is much safer and simpler to direct wire any inverter to its own breaker.
I am not that familiar with the difference between a "GTIL" inverter and a true hybrid unless it is the islanding functionality. Most Hybrid inverters have the option to add an external CT and limit export.. Do these GTIL inverters with batteries have built in automatic transfer switches? Does the export limiting qualify as a UL approved islanding function?
 
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fafrd

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I would not encourage a configuration that plugs into just "any" outlet. To be safe that outlet needs to be on a dedicated breaker. I believe that is consistent with the building code. That being said, it is much safer and simpler to direct wire any inverter to its own breaker.
I would’t encourage it either and while there are no specific guidelines in the manual, I elected to wire-in a new 10A split-phase circuit connected to a new outlet pair (one 120V outlet on each phase) dedicated to this purpose.

So the wiring complexity is pretty much the same as that involved in wiring up a new 240V outlet…
 

Ampster

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How about islanding? When the grid is down, other than the CT, how does it prevent backfeed? The reason I am asking is that even with a CT there is some slop and while that is not significant in terms of Net Metering it could be a safety hazard and not complant with codes or UL.
 

fafrd

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How about islanding? When the grid is down, other than the CT, how does it prevent backfeed? The reason I am asking is that even with a CT there is some slop and while that is not significant in terms of Net Metering it could be a safety hazard and not complant with codes or UL.
The GTILs are ‘powered’ by the grid. Like any other gridtie inverter, when the grid goes down, they shut down.

And that is the reason they do not provide backup capability.

I have a totally separate 3kW PSW I will turn on manually after shutting off the main breaker to power my fridges off of battery energy during extended grid outages.

A pure grid-tie inverter such as a Microinverter will convert all available input power to AC power (at least up to its rated maximum).

A pure off-grid inverter will convert as much energy to AC power as needed to supply loads (at least up to its rated maximum).

A GTIL inverter will convert as much energy to AC power as needed to drive grid consumption to 5-10W (at least up to its maximum output).

GTIL inverters are not compliant with code and I have not yet seen any with UL rating, but I don’t believe they represent any more of a safety hazard than any other 1kW appliance…

It’ll be interesting to see whether the Powers That Be ever ‘allow’ GTILs to be certified for use here in the US.
 

Ampster

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It’ll be interesting to see whether the Powers That Be ever ‘allow’ GTILs to be certified for use here in the US.
The Powers That Be do allow grid tie inverters with current limiters to be used. Here is is important to distinguish which Powers That Be you are referring to.
As far as the building code is concerned, any grid tied inverter that is UL approved can be installed with just a building permit in most places. For example my current Enphase micros can be configured for non export and I am of the opinion that if I do not export I do not have to apply for a Permission To Operate. The only exception are cities with municipal utilities like LADWP in which case the AHJ and the power company are the same and may have regulations that prevent that.
I do not think the building codes will ever be relaxed to the point of allowing non UL approved Inverters to be permanently attached to household circuits. I honestly do not know if a GTIL connected through a plug and receptacle is considered temporary like a generator.
 

fafrd

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The Powers That Be do allow grid tie inverters with current limiters to be used. Here is is important to distinguish which Powers That Be you are referring to.
I’m interested in any UL-Listed GTILs that can be connected in parallel (in-the-critical-path hybrids not included).
As far as the building code is concerned, any grid tied inverter that is UL approved can be installed with just a building permit in most places. For example my current Enphase micros can be configured for non export and I am of the opinion that if I do not export I do not have to apply for a Permission To Operate.
I believe that is correct.

Micro-inverters under control of a centralized battery/storage system to assure all unconsumed generated power is either used to charge the battery or the micros are forced to taper-back production is the other attractive alternative to achieving the same end-result.

If we don’t see UL-approved GTILs by the time I’m putting together my ‘final’ build in a couple years, that may be the direction I go.

What are you using to control your Enphase Micros and does it need to be wired into the critical path like a hybrid inverter or can it connect on parallel through it’s own circuit like a GTIL?


I do not think the building codes will ever be relaxed to the point of allowing non UL approved Inverters to be permanently attached to household circuits.
No, I don’t believe permitted installs will ever allow installation of non UL-approved equipment.

The ‘Powers That Be’ that I was referring to was UL itself. I’m not aware if anyone has attempted to get one of these GTIL inverters through the UL approval process or not yet ($$$expensive).

I honestly do not know if a GTIL connected through a plug and receptacle is considered temporary like a generator.
I’m not aware of any permitted/listed installation of a generator that allows it to be powered and supplying loads in parallel with the grid. Off-grid or separate island, fine, but supplying power in parallel with the grid requires a listed hybrid inverter (from what I’ve understood).

A generator including a solar generator can be connected up to one or several appliances (ie: with extension cords) but I’m not aware of any permanent installs that don’t require use of a transfer switch so generated power is essentially off-grid (again, except in the case of a hybrid inverter).

Appliances that consume power can be connected to any outlet and the ‘grey area’ exploited by these GTIL inverters is that they are essentially configured as appliances that generate a bit of power rather than consume a bit of power.

The better proxy might be a UPS for a computer. Those are listed but they only kick-in when the grid goes down and they only power a dedicated socket/appliance.

A UPS could be designed so that is powers the appliance/computer during peak hours and recharges the battery during off-peak hours.

I’m not aware of any UPSes that do that and in any case, we’re still talking about serial connection versus parallel connection, but it’s still a closer analogy than a generator that typically cannot be operating while the grid is live (without a hybrid inverter).
 
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