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Dumb Question Regarding the Growatt 12kW 48V 250VDC 120A Off-Grid Inverter

J.P.

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I installed my new 12kw 48V Growatt Inverter today and I am not getting the expected output.

The manual says for 240V installation to NOT hook up the Neutral wire from the output. I get 240V across H1 & H2 but only 75V from H1 to Neutral/Ground and 75V from H2 to Neutral/Ground. Is something wrong with the inverter? How do I get normal USA 120V on both H1 & H2 for our normal single phase 120V + 120V = 240V USA electricity?
 
I would try putting a load on it between one side and the neutral.... Like an old style light bulb or heater...

In an guessing you are not measuring it under load and it can float to odd values...
 
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I would try putting a load on it between one side and the neutral.... Like and old style light bulb or heater...

In an guessing you are not measuring it under load and it can float to odd values...
I know that loading one side (HOT1) with the Neutral, or the other side (HOT2) with the Neutral will give 120V. The manual calls that out as one of the wiring options and I have tested it. What I am not sure of is using both legs (simultaneously) because the manual specifically states using (HOT1 + N) OR (HOT2 + N). I am really hoping the answer is that you can use both so I can get standard USA 120+120=240 Voltage but if that was the case why does it not just give that as an option? I am really hoping that this is not one of those inverters that requires a seperate transformer to run 120+120=240 Voltage. That would be a huge disappointment.
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I do agree that their wording in the manual does not state it will work, but the advertisements do say split phase...

I was close to buying one but haven't.
 
I have this unit, and the manual misleads you here. I believe they are saying in the first diagram that **if** you only have 240v load you wire the output that way.

If you want 120v as well you will need to bring the *inverter transformer neutral* to the load (they don't provide a split-phase diagram for some odd reason). Also your input *Ground* (terminal 3 from the left) is not the grid Neutral.

Input to the inverter is L1+L2+GRD from a mains panel or generator
Output from the inverter is L1+N+L2 to critical load(s)/panel

Install a chassis ground as well.

Check out AveRage Joe on YouTube he installed this same unit.

Edit: L1=H1, L2=H2, If you wire as stated above you will have the ability to support 120v and 240v loads, no separate auto transformer needed. This low-frequency off-grid inverter has a big transformer inside it (that's why it weighs 150lbs).
 
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I have this unit, and the manual misleads you here. I believe they are saying in the first diagram that **if** you only have 240v load you wire the output that way.

If you want 120v as well you will need to bring the *inverter transformer neutral* to the load (they don't provide a split-phase diagram for some odd reason). Also your input *Ground* (terminal 3 from the left) is not the grid Neutral.

Input to the inverter is L1+L2+GRD from a mains panel or generator
Output from the inverter is L1+N+L2 to critical load(s)/panel

Install a chassis ground as well.

Check out AveRage Joe on YouTube he installed this same unit.

Edit: L1=H1, L2=H2, If you wire as stated above you will have the ability to support 120v and 240v loads, no separate auto transformer needed. This low-frequency off-grid inverter has a big transformer inside it (that's why it weighs 150lbs).
Thank you! That is the answer I was hoping for from someone who already owned and installed one of these.
 
I have this unit, and the manual misleads you here. I believe they are saying in the first diagram that **if** you only have 240v load you wire the output that way.

If you want 120v as well you will need to bring the *inverter transformer neutral* to the load (they don't provide a split-phase diagram for some odd reason). Also your input *Ground* (terminal 3 from the left) is not the grid Neutral.

Input to the inverter is L1+L2+GRD from a mains panel or generator
Output from the inverter is L1+N+L2 to critical load(s)/panel

Install a chassis ground as well.

Check out AveRage Joe on YouTube he installed this same unit.

Edit: L1=H1, L2=H2, If you wire as stated above you will have the ability to support 120v and 240v loads, no separate auto transformer needed. This low-frequency off-grid inverter has a big transformer inside it (that's why it weighs 150lbs).
I completely agree, that is how I saw it... Thanks for taking the time write it up.
 
I agree , the inverter input will not need a neutral connection as it is 240 only and cannot use 120 volt input but to have 120/240 volt output the neutral must be connected, not all will be wired this way! Sometimes the translation sucks and they mean one thing but when you hear it it’s not what was meant.
 
If you want 120v as well you will need to bring the *inverter transformer neutral* to the load (they don't provide a split-phase diagram for some odd reason). Also your input *Ground* (terminal 3 from the left) is not the grid Neutral.
as Grid Neutral and ground are tied together at the main panel of the house. For all intents and purposes it is. Granted the ground is not intended to be a current carrying conductor, however for the growatt it serves to "center" the split phase by giving it a 0 reference for the output neutral.
 
Schism,

That may be true or not.....some inverters can run in 2 wire input and via their output transformer provide a neutral from there to provide 120/240 split phase, The neutral output of the inverter is in relation to the inverters output....not the input of the inverter. Keep in mind when you are running from the inverter, your power is coming from the inverter not from the POCO,

If you were to bring neutral from the main panel then it would be connected to the neutral output of the inverter, on multiple source systems almost always you keep a continuous bond on the neutral.

In any case you are only allowed to bond neutral to ground in one place and one place only so what you are doing is bonding neutral to ground in the main box then again in the inverter. This is a violation of the NEC and will cause “circulating currents” in the ground wire which will cause nuisance tripping of GFCI devices

Strongly suggest that you verify what I said with a power professional
.......Retired from GE as electrical engineer......

david
 
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Great explanation @Tecnodave! The Growatt discussed here is indeed a “grid forming” (provides voltage and frequency) inverter and operates exactly as you state in your first paragraph.

I think the rest of your post should be expanded into 2 knowledge base articles on bonding and “separately derived systems” as these are topics that us DYIer’s could easily confuse.
 
Curious to see if you have it resolved, per signaturesolar and growatt the neutral is required.
 
I too was thrown off by the instructions. I wired my SPF6000T with L1, L2, and N directly into my breaker panel (off-grid setup). My panel has 120V 20A breakers for the house circuits and 240V 30A dual pole breakers for two mini-split air conditioners. Everything is working excellently. Super happy with the Growatt.
 
Curious to see if you have it resolved, per signaturesolar and growatt the neutral is required.
Yes. jrscarlett in Post #5 above has it correct. When I wired it that way, the output is split phase (120 + 120 = 240) as expected.
 
Does anyone see an issue with wiring both the GRID Neutral and the inverter Neutral together in a sub-panel? I wanted to have an interlock switch that would power the subpanel from either the inverter output or the grid. The hots would be isolated but the neutrals would be constantly bonded. Note that whilst on grid power the inverter would be powered off (although the interlock would not prevent the operation with the inverter powered but the hots disconnected). The subpanel would not bond the Neutral and GNDs together
 
on my off-grid system, my generator ("grid") neutral goes to my main panel neutral bus, and so does my Growatt inverter neutral, as do all neutral wires in the house. I don't have any subpanels and my main panel does not have neutral connected to ground anywhere. works great I have the Growatt set to utility first, so that it runs off solar all day long but in the event I need help I warm up the generator, flip a switch to supply 240V generator power to the Growatt and it automatically powers the house off the generator and charges the batteries.
 
Does anyone see an issue with wiring both the GRID Neutral and the inverter Neutral together in a sub-panel?
I had this same concern. Probably not a problem, but I use a 3 pole transfer switch to insure isolation. That way no connection to the inverter at all when not in use.
 
How does this unit handle large inductive loads like starting a well pump, air compressor or large miter chop saw? Is it UL approved?
 
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