Eg4 moving in the right direction

[Cheap 4-life]

The EG4 inverters seem like a reasonable option. They are priced right and look to be well built. I can say the same about the server rack batteries.
I’m hoping their inverters keep advancing. What I mean by that is I’m hoping/wanting them to become what I’d call a true hybrid. Meaning that they could also output grid tie power and utilize Cts/coils on the homes mains wires for zero export. Almost every major manufacturer (and even lesser manufacturers) now make inverters that have the ability to use coils on the homes mains wires to do zero export. It would help them sell a lot more inverters as most people are not fully offgrid.. most have to pay a minimum fee to keep grid power connected to their homes. The best option for those users to come very close to zeroing their electric bill is to have an inverter that does zero export and supplies power directly to the main panel. Then for the rare power outages they can have a small critical panel with just the critical loads in it. The user can also have a much smaller battery bank (dramatically lowering cost of the setup) due to only needing to power a few loads offgrid during a rare power outage. The inverters grid connection also known as AC charging connection would need to be bi-directional. This would enable the inverter the possibility of disabling AC charging when in grid tie mode and then utilize that grid connection to supply grid tie power directly to the main panel. Of course the battery would also need to also be utilized by the grid tie output of the inverter to come close to zeroing out the power usage during cloudy days and to keep the grid tie portion of the inverter running thru the night for 24/7 zeroing of the electric bill.
Maybe their best move would be to start with a grid tie inverter that can utilize batteries and CTs. Then after that’s out and selling well they could combine that with a the new splitphase eg4 to have a true hybrid for sale and dominate the market

 

[timselectric]

I never understood the reason for "zero export grid-tied" . If you have no intention of exporting, why bother with the additional cost of a grid-tied inverter?
(Honestly curious)
My off grid Growatt SPF-5000-ES can power my loads and let the grid take the surges, and make up for any shortage of power. The batteries can be saved for power outages only, if desired. (SUB mode)

Or it can let solar power the loads and batteries will fill in the gaps. When solar isn't available (nighttime or cloudy/ rainy days), the grid takes over. (Solar first mode)

Or it can be just solar and batteries, with grid as a backup. (SBU mode)

What does grid-tied offer, that I don't already have?
Maybe I am missing something.

 

[Cheap 4-life]

my Setup consists of cheap grid tie inverters. They are 2kw each and were $300 each. So the cost was minimal and cheaper than most offgrid inverters. The big money saver when using battery powered grid tie inverters with zero export is not needing a battery bank/inverter that is large enough to cover surges and occasional high loads. The inverters can be sized to cover the majority of the homes loads 24/7 and simply let the grid cover the rare high loads that as I said are most of the time rare and don’t cost much to let the grid supply. That means the inverter capacity can be a lot smaller. My two grid tie inverters put out 4kw combined and that almost always covers all of my homes loads and would do the same for most homes, but I do have occasional 12kw of loads from multiple things being on. I would need a much larger much more expensive offgrid inverter to cover the rare 12kw loads.
Furthermore money is saved by only having very critical load moved to a smaller critical loads panel for the rare power outages that most people experience. I have a cheap offgrid inverter wired to a manual switch for the critical panel that will rarely get used, only used twice in three years. I also have a spare because it was so cheap. Most would be fine simply powering the essentials for the short duration power outages. If power outages were permanent (SHTF) then I and most people would be grateful that they can power the essentials.

How does your offgrid inverter allow grid power to be mixed with its output if the offgrid inverter cannot feed back into the grid? If the offgrid inverters output can power the same load as the grid at the same time then what stops it from backfeeding into the grid? Are you saying that if your loads in the critical panel exceed the capacity of your inverter while inverter is using batteries and pv, that your inverter continues to supply its max output and the grid (at the same time) simply supplies the remaining amount those same loads in critical panel need? All while not backfeeding? I was under the impression that when the amount of kw the loads in the critical panel need exceeds an offgrid inverters max capacity that the offgrid inverter shuts off and the grid takes over supplying the critical panel. Then the offgrid inverter does like a check every so often and tries to again power the critical loads panel..

 

[timselectric]

It appears that I have all of the same features that you described. And yes, my inverter can share the loads between solar and grid. With the battery waiting as a UPS. Battery replaces grid, if the grid goes down. And solar can't handle all loads. In this mode (SUB) you don't even have to have a battery connected.

 

[Cheap 4-life]

Ah so your inverter can’t use batteries when the grid is helping? That’s a big difference between your inverter and a grid tie inverters I’m describing.
Still don’t understand how the grid can supply a load in your critical panel at the same time as the offgrid inverter is powering that critical panel. Is the offgrid inverter allowing grid power to pass thru the inverter to the critical panel while the inverter continues to use batteries and pv (If pv is available) to supply the critical panel?

 

[Hedges]

But does yours only do that for power fed through inverter (like UPS) to loads?
Three issues with that:
1) Needs to be beefy enough, perhaps 100A or 200A pass-through.
2) Needs to be installed in-line
3) Your power is now only as reliable as GRID && Inverter, rather than GRID (regardless of inverter condition.)

"Zero export" means having a current transformer on utility feed, so inverter backfeeds power to the house but not to the grid.

 

[Cheap 4-life]

Grid tie inverters able to utilize a battery to power loads and at the same time allow the grid to handle surges and occasional/rare higher loads allows for a good bit more money to be saved on the electric bill. These inverters just keep on running and using batteries whenever needed if solar isn’t enough. This also allows for the inverters/batteries to simply be sized to cover the homes more constant high load. Also worth mentioning that a critical loads panel doesn’t even necessarily need to be installed. The grid tie output is wired directly to the main panel. However most people would want at least a small critical panel with a few critical loads moved there from the main panel for rare power outages to utilize their pv panels when the powers out. Of course the grid tie inverter supplies that critical panel until the power goes out

 

[timselectric]

In SUB mode it draws the first 500w from the grid and the rest from solar if available. This is how it keeps from backfeeding the grid. It provides time for the inverter to react to changing demand. The AC output is paralleled with the AC input, and inverter output.
And you are correct about not having the ability to use battery and grid together. In this mode, the battery can only be charged by either solar or the grid. Depending on the settings you choose. Unless the grid goes down. Then the battery takes over.

 

[Cheap 4-life]

So your saying that no matter what your growatt (in SUB mode) is allowing the grid to supply the first 500w of the load? If so that’s a big difference, the grid tie with zero export supplies all of the homes loads and only allows loads to utilize grid power at the same time if the inverters capacity is maxed. Of course a small 10w to maybe 50w is always being used from the grid to prevent backfeed

 

[timselectric]

I've measured it at around 2a at 240v. I'm just approximating 500w. But yes, that's how it works.
I chose this inverter for this feature, among others.
It allowed me to start small and scale up as funds and time became available. I started with a single inverter and 5k of solar, connected to a critical loads panel.
This gave me electricity bill savings during the day.
Then, I added the first battery for savings at night too.
Now I have added more solar and battery storage. Which allowed me to move more loads to off grid. (Half of the house currently) and I will continue to scale up, until the entire property is off grid. (Within the next 2 years)

 

[Cheap 4-life]

I hope I have satisfied some of your curiosity regarding zero export grid tie. It saves you more money on electric bill than an offgrid setup unless your fully offgrid 24/7. If a home has a grid connection then grid tie with batteries and zero export is a more cost affective approach. The system is much cheaper to get going. Yes if your goal is to have ALL your homes loads offgrid then buying grid tie inverters at all most likely does not make sense. For most people they would want to simply get their electric bill as low as possible. Grid tie inverters capable of utilizing batteries and zero export is the way to do that. Most people have very rare power outages and do not need all of their homes loads to be powered off grid. A small essential/critical loads panel is all that’s needed for most. This is why I started this post so EG4 could notice the demand for a “true” hybrid inverter as I explained. SolArk/Deye, Schneider, Outback and many others have the ability to do grid tie zero export and use batteries at the same time. Grid tie inverter with zero export and utilization of batteries has more savings on the power bill and lower cost of the battery bank and lower cost due to smaller size inverter needed to cover just the homes constant loads.

 

[timselectric]

Yes, I enjoyed the conversation. And it probably helps others see what options are available to accomplish their goals.
Self reliant is my goal. Once I complete the solar and drill my well. I will only have a wireless connection to the rest of the world.