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How to wire my 12KW Growatt Inverter using a Hybrid Solution

Cabo35

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Jul 11, 2022
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Hello All,

I'm attempting to draw a wiring diagram for myself before I install my Growatt 12Kw inverter and assistance is greatly appreciated from the community since I'm very Green and a newbie. The attributes for discussion are below..

Please review the installation and 12kw Growatt SPEC SHEET.
  • SPF 12000KT DVM-US MPV

1a). I have a split phase (120V/240V) North American electricity supply with (L1 N L2) wires currently connected to my MAIN breaker panel from the meter with (L1 N L2) wires.

2a). My MAIN A/C breaker panel is in the main part of the home, I believe its an 100amp breaker box with multiple breakers to supply electricity to 120V and 240V loads throughout the main part of the home

3a). I have another sub panel connected to lights, washer/dryer, whole house water pump, etc. also with 120V and 240 loads.. Not sure about the total amperage on the subpanel breaker box to power the loads mentioned above in the home. There is no separate building for the existing subpanel. The subpanel is located in another part of the house.


I want to install a hybrid solution for my home and use the Electrical Grid for Grid-assist only in case I need maintenance on the solar equipment, or for some reason I do not produce enough kilowatts for some reason. There will be no selling back electricity to the power company(net metering). Also, I want to wire a new A/C Breaker Panel next to the Growatt 12kw inverter. I want to configure the wiring below as follows:

1b). I need to disconnect the (L1, N, L2) from the meter/grid(With assistance from a licensed electrician of course) and connect the (L1, N, L2) to a new A/C breaker box installed next to the Growatt inverter. The (L1, N, L2) wires will be used for the A/C INPUT in to the new A/C breaker box for grid-assist, and then wired to the A/C input terminals to the 12Kw Growatt inverter(Need advice on terminal connection to Growatt A/C INPUT) since this model of Growatt has A/C INPUT for (Hot-1, Hot-2, and Ground) terminal connections

Q: How shall I wire this correctly with new A/C breaker panel for split phase from the new A/C breaker panel to the Growatt inverter, since you only have an Hot-1 and Hot-2, and a Ground terminal connection on the A/C INPUT side of the 12Kw Growatt, and no Neutral terminal on the A/C INPUT side of the Growatt?

2b). I also need to wire the split phase(120V,240V) A/C output terminals(Hot-1, N, Hot-2) from the 12Kw Growatt inverter back to the new A/C breaker box, and in to the Main breaker panel in the home(L1,N,L2). I don't want to touch the already existing Main A/C breaker panel in the home, or the existing subpanel in the home. I just want to connect the (L1, N, L2) lines coming out from the new A/C breaker panel and back to the Main panel (L1, N, L2) connections in the home.

Q: Would this be the correct way to wire my specific configuration for the A/C output from the Growatt inverter?

Q: Is there anything special I have to wire in the new A/C breaker panel first before connecting any wires from the meter, or from the Growatt inverter?


The new A/C breaker panel and all the solar equipment, breakers, batteries etc, will be located in a separate stand-alone concrete shed..


Ok, I hope that I'm not confusing and way off base here with the wiring, and I'm sorry I had to talk this out instead of putting my thoughts on paper with a draft diagram. I appreciate the community assistance. Again, the electrician I'll be working with will assist me, but I want to make sure I understand what's going on, so we all are on the same page.

Respectfully,
Cabo35
 
Last edited:
I intend to do very similar work. I'll keep my eyes out for a solution and post here if I find one. I would greatly appreciate the same.
 
Ground and Neutral are bonded only once in any system, at the main panel closest to the meter.


I have output from the inverter into my main panel. I use the entire main panel as the "sub panel" from the inverter. The inverter is on a breaker just like any other generator setup. When I do this, I disconnect the main circuit breaker from the meter.

I can also take input from the grid to charge my batteries if I don't have enough solar. The lets me use the same breaker in the panel to go to the input of the inverter. I use a giant A/B knife switch so it is physically impossible to have both input and output at the same time on the same circuit.
 
I intend to do very similar work. I'll keep my eyes out for a solution and post here if I find one. I would greatly appreciate the same.
Will do... As soon as I find out, I'll do the same.
 
Ground and Neutral are bonded only once in any system, at the main panel closest to the meter.


I have output from the inverter into my main panel. I use the entire main panel as the "sub panel" from the inverter. The inverter is on a breaker just like any other generator setup. When I do this, I disconnect the main circuit breaker from the meter.

I can also take input from the grid to charge my batteries if I don't have enough solar. The lets me use the same breaker in the panel to go to the input of the inverter. I use a giant A/B knife switch so it is physically impossible to have both input and output at the same time on the same circuit.
Thank you
 
Transformer based Split Phase output LF inverters like the GROWATT SPF-4000-12000T (AIMS POWER, SIGNEER,...etc. ) come with their challenges in regards running them as a "Hybrid" or "UPS" solution while being in accordance to code and not overload/destroy them.
Issue #1: Charging of the battery from the power input only or in conjunction with the Solar input will only function while the inverter is in bypass mode so input L1 and L2 is passed through to Hot1 and Hot2 output respectively with the inverter transformer secondary windings connected to grid L1 and L2 with a new Neutral output, that brings us to issue 2.
Issue #2: Grid Neutral and Inverter Neutral output should never be interconnected while the inverter is in bypass mode as this can cause an overload of the inverter or at minimum a parasitic load depending on the upstream L1-N & L2-N imbalance from the grid connection.
Issue#3: Bonding due to issue #1&2
Issue#4: Earth Ground due to issue #1&2

Many of the Autotransformer Split phase discussions within this forum also apply to these LF transformer based Inverters since their output transformers pretty much works as such an Autotransformer by creating a new Neutral. Lots of discussions about, some heated with some solutions but IMO no silver bullet perfect solution possible.
 
This is how I wired my SPF12000 to automatically switch to util only when the battery gets low (the automatic switch performed by the growatt is seamless).
I added a 200A 2 pole switch transfer (knife) switch to select util/solar (I only use it in case of maintenance). It only switches L1/L2 (N is not switched and remains connected in the main panel).
I installed a 70A (inverter breaker) from the util (input) side of the transfer switch to the inverter util AC input (L2/L2 only). The inverter ground is connnected to the main panel ground. This breaker supplies util power to the inverter always. It has to be a seperate breaker (not in the main panel).
The AC out L1/L2 of the inverter is connected to the transfer switch (solar input). The N is directly connected to the main panel nuetral.

The only changes to my breaker panel was to feed it from the transfer switch and connect N and G to the inverter.

Everyone may not know this, but you can set some configuration values in the growatt app that you can't using the inverter front panel.
I can set my battery to utility and utility to battery setpoints higher in the app than it allows on the front panel. Also you will notice additional settings such as time of day charging etc.! I attached screenshot.Screenshot_20221130-083709_ShinePhone.jpg
 
Everyone may not know this, but you can set some configuration values in the growatt app that you can't using the inverter front panel.
I can set my battery to utility and utility to battery setpoints higher in the app than it allows on the front panel. Also you will notice additional settings such as time of day charging etc.! I attached screenshot.
Yes you see some extra adjustments on the app or Dashboard Web but those most likely won't do anything on this inverter if changed even if you get a "success" reply when sending the change. Btw it also did send me a "success" after updating my Wifi Dongle which bricked it thus a success in the app may not be a success for the User.
 
Yes you see some extra adjustments on the app or Dashboard Web but those most likely won't do anything on this inverter if changed even if you get a "success" reply when sending the change. Btw it also did send me a "success" after updating my Wifi Dongle which bricked it thus a success in the app may not be a success for the User.
I have been using the settings and they function as set in the app. Also I can view the updated settings on the inverter panel.
I shared your doubts before I tested the settings.
 
I have been using the settings and they function as set in the app. Also I can view the updated settings on the inverter panel.
I shared your doubts before I tested the settings.
What I'm referring to is Charging/Output period end/start time for example, you can set it in the phone app and get a successful reply when send but it will do nothing whereas the web app will at least give you a set parameter failure.
However yes you can set certain values with a wider range in the phone & web app, e.g. finer increments than you can directly on the inverter panel.Growatt_setParafail.JPG
 
This is how I wired my SPF12000 to automatically switch to util only when the battery gets low (the automatic switch performed by the growatt is seamless).
I added a 200A 2 pole switch transfer (knife) switch to select util/solar (I only use it in case of maintenance). It only switches L1/L2 (N is not switched and remains connected in the main panel).
I installed a 70A (inverter breaker) from the util (input) side of the transfer switch to the inverter util AC input (L2/L2 only). The inverter ground is connnected to the main panel ground. This breaker supplies util power to the inverter always. It has to be a seperate breaker (not in the main panel).
The AC out L1/L2 of the inverter is connected to the transfer switch (solar input). The N is directly connected to the main panel nuetral.

The only changes to my breaker panel was to feed it from the transfer switch and connect N and G to the inverter.

Everyone may not know this, but you can set some configuration values in the growatt app that you can't using the inverter front panel.
I can set my battery to utility and utility to battery setpoints higher in the app than it allows on the front panel. Also you will notice additional settings such as time of day charging etc.! I attached screenshot.View attachment 122349
Hi! How is your Growatt performing so far? Is d common neutral causing any problems?
 
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