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EG4 8k/megarevo Hybrid inverter zero export

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ddeatrich

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Joined
Sep 11, 2022
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Hey guys,

I set up an EG4 hybrid inverter in my home. I have 8000 watts of PV input and I have the grid input plugged into a double pole 40AMP breaker in my main panel. Grid input is bidirectional so it outputs through the grid input port. I installed CTs in my main panel pointing to my breaker panel, turned them and pointed them to the grid, switched the ethernet cables inside multiple times. My inverter is consistently inputting 5 watts on all 3 solar strings.

When I turn off Anti-Reverse, it starts pulling 6000 watts from the panels. I'm trying to power my home without exporting to the power grid so anti reverse needs to be enabled. As soon as I turn on Anti-Reverse, it starts pulling only 5 watts again. I'm on the latest firmware from EG4. I tried megarevo firmware too and it's the same thing.

How do you properly set up the CTs and get anti-reverse working? I seemed to have tried everything.
 
Could you post your model and perhaps a link to its manual? Seems like the AC in should not be used for AC out when using anti-reverse. But I am just guessing since I am not familiar with grid tie hybrids.
 
dcg9381 said:
Eh? Isn't that grid tie? I'm a little curious.
Click to expand...
Yeah, it is grid tie. I don't have batteries at the moment but that's the benefit of having a hybrid inverter. You can grid tie until you get batteries or whatever mode you want, really.
 
According to the manual Anti-reverse prevents sending power to grid. So you would not enable it . However to setup your CTS and zero export is hard to figure out from a quick read of the manual. (Grid power percent?). Hopefully someone with more familiarity can chime in or you may need to consult your hybrid supplier.
 
Mattb4 said:
According to the manual Anti-reverse prevents sending power to grid. So you would not enable it . However to setup your CTS and zero export is hard to figure out from a quick read of the manual. (Grid power percent?). Hopefully someone with more familiarity can chime in or you may need to consult your hybrid supplier.
Click to expand...
I did consult the supplier. They said there isn't really a manual yet LOL so this is what I have to resort to. They told me "we dunno, we'll research it" but they're probably just going to see these same forum posts lol
 
Is the eg4 capable of zero export as a grid tie inverter by using CTs. Last I heard it has the ports for the CTs but the firmware wasn’t currently capable, but would be in the future.
but anyways you would want power being sent to your main panel via the inverters grid port. Anti reverse would most likely prevent that. I’m thinking Anti reverse isn’t to stop power from going past your main panel and to the grid but rather to stop power from exiting the inverters bi-directional grid input, meaning turning anti reverse on would stop the grid port from being bidirectional so power couldn’t go in the reverse direction.
 
Last edited:
fromport said:
The EG4 manual has the CT's for L1 & L2 switched
See https://diysolarforum.com/threads/megarevo-rxlna-discussion.36290/post-691608 and further.
Look at the PCB underneath the RJ45 connector for the correct location.
Click to expand...
Thanks!!! Reading through all of this now.

Cheap 4-life said:
Is the eg4 capable of zero export as a grid tie inverter by using CTs. Last I heard it has the ports for the CTs but the firmware wasn’t currently capable, but would be in the future.
but anyways you would want power being sent to your main panel via the inverters grid port. Anti reverse would most likely prevent that. I’m thinking Anti reverse isn’t to stop power from going past your main panel and to the grid but rather to stop power from exiting the inverters bi-directional grid input, meaning turning anti reverse on would stop the grid port from being bidirectional so power couldn’t go in the reverse direction.
Click to expand...
Oh that's pretty good thinking. That sounds exactly like what's happening. I'll do some more testing tomorrow with it disabled and see what happens.
 
ddeatrich said:
Thanks!!! Reading through all of this now.


Oh that's pretty good thinking. That sounds exactly like what's happening. I'll do some more testing tomorrow with it disabled and see what happens.
Click to expand...
Would really like to know if you get it workin. I havnt heard/read anyone confirming that CTs and zero export now work with the Eg4 8k hybrid. When I asked Eg4 a few months ago they had no idea what I was talking about but ended up saying that would be in future firmware updates
 
ddeatrich said:
I did consult the supplier. They said there isn't really a manual yet LOL so this is what I have to resort to. They told me "we dunno, we'll research it" but they're probably just going to see these same forum posts lol
Click to expand...
Then it is possible that your only modes of operation is to wire AC in from your main panel and then AC out to a separate panel that supplies the loads that you need. If you want to export (and power your Main panel) you would have anti-reverse off.
 
For what it is worth, I installed my EG4 8K this weekend and the grid-tie with limiting is working for me: the unit is feeding just enough power back to the 40amp grid connection to offset my home's usage without exporting any power to the utility company. This is with the CTs installed in the main panel and anti-reverse enabled (default setting on my unit, which I think was different than the manual said was default). If I disconnect the CTs entirely then it completely stops feeding any power to the grid connection with anti-revers enabled. Seems to be working exactly as I hoped it would.

I'm a little unclear from your description as to where exactly you have the CTs so just to be clear: the CTs should be installed on the main power lines between your utility meter and your main breaker, with the arrows pointing towards the utility meter/connection (at least with the equipment that came with my unit). In my case, with a 220 split phase, this is on the two hot wires coming from the utility meter to the 100amp main breaker in my main panel.

My only complaint right now with this part of my setup is the app/website doesn't clearly display the power being created on the grid feed connection, I have to look at the solar wattage and the battery wattage and do the math in my head to know how much is being inverted for grid feed, but that is a problem for another day.

#edited to fix disabled/enabled for anti-reverse setting description.
 
Last edited:
stephenwolf2 said:
I'm a little unclear from your description as to where exactly you have the CTs so just to be clear: the CTs should be installed on the main power lines between your utility meter and your main breaker, with the arrows pointing towards the utility meter/connection (at least with the equipment that came with my unit). In my case, with a 220 split phase, this is on the two hot wires coming from the utility meter to the 100amp main breaker in my main panel.
Click to expand...
So, really basic question here - I've never seen a system like this. In my experience the utility allows grid tie (and you get permitted for it) or you stay off the grid.

What's a CT?
 
dcg9381 said:
So, really basic question here - I've never seen a system like this. In my experience the utility allows grid tie (and you get permitted for it) or you stay off the grid.

What's a CT?
Click to expand...
IIRC a CT is a current transformer. It is basically a coil that you put around a current carrying conductor to read amperage. Same idea as a clamp on ammeter. Placed around the wire one way it reads amperage in one direction as positive and amperage in the other direction as negative. Turned around and it does the exact opposite.

So the theory of operation is the CT coils are placed on grid incoming wire to determine if you have a negative amperage flow (back feeding the grid). Your zero export feature of the hybrid acts to prevent this by decreasing your inverter output. There should be an ability to set a minimum of positive amps coming in to overcome transients that could cause feeding the grid inadvertently.
 
Mattb4 said:
IIRC a CT is a current transformer. It is basically a coil that you put around a current carrying conductor to read amperage. Same idea as a clamp on ammeter. Placed around the wire one way it reads amperage in one direction as positive and amperage in the other direction as negative. Turned around and it does the exact opposite.
Click to expand...
Got it. I have those on my energy monitoring systems. Basically the inverter is determining "neutral" if the CT is reading zero current either way.

Here grid tie is required to shut down if the grid goes offline. Does this type of system work like that?
 
dcg9381 said:
Got it. I have those on my energy monitoring systems. Basically the inverter is determining "neutral" if the CT is reading zero current either way.

Here grid tie is required to shut down if the grid goes offline. Does this type of system work like that?
Click to expand...
Anti-islanding is accomplished by the device being able to see the sudden drop of grid frequency (I am a bit hazy if voltage has any part to play in it.) Perhaps one of those that are more knowledgeable about how it all works can clear up any of my mistakes in explanation.

Living in Arkansas some of the rules are different than the country of Texas has but basically we have the same for what is grid tied. You need an interconnect agreement if you parallel with the grid. Export or not. No ifs, buts or ands.
 
Last edited:
stephenwolf2 said:
For what it is worth, I installed my EG4 8K this weekend and the grid-tie with limiting is working for me: the unit is feeding just enough power back to the 40amp grid connection to offset my home's usage without exporting any power to the utility company. This is with the CTs installed in the main panel and anti-reverse enabled (default setting on my unit, which I think was different than the manual said was default). If I disconnect the CTs entirely then it completely stops feeding any power to the grid connection with anti-revers enabled. Seems to be working exactly as I hoped it would.

I'm a little unclear from your description as to where exactly you have the CTs so just to be clear: the CTs should be installed on the main power lines between your utility meter and your main breaker, with the arrows pointing towards the utility meter/connection (at least with the equipment that came with my unit). In my case, with a 220 split phase, this is on the two hot wires coming from the utility meter to the 100amp main breaker in my main panel.

My only complaint right now with this part of my setup is the app/website doesn't clearly display the power being created on the grid feed connection, I have to look at the solar wattage and the battery wattage and do the math in my head to know how much is being inverted for grid feed, but that is a problem for another day.

#edited to fix disabled/enabled for anti-reverse setting description.
Click to expand...
So, I have my CTs currently on the lines like you have yours. My CT arrows are pointing to my breaker panel now, NOT out to the grid with anti-reverse enabled.

I don't have batteries in my system yet. I'm just connected with the grid inputs from 40 amp breaker in the breaker panel to the inverter.

Self consume wouldn't work no matter what I did. I turned on battery priority mode instead even though I don't have batteries and the inverter is actually working correctly now. I am able to use my solar to offset my loads in the house without exporting to the grid. I've confirmed this by checking my electrical meter in the morning before sun up and taking photos, then comparing to later in the day. The meter is staying exactly the same.

I switch back to self consume mode and everything breaks again. You say you have your CTs pointed towards the grid with anti-reverse enabled and yours is working correctly. So this is weird then. Apparently pointing them both ways work the same? This doesn't make sense to me at all.

I've heard some people say Megarevo CTs are backwards though. I purchased an EG4 inverter but flashed Megarevo firmware on it. Could this be why? Maybe EG4 has different CTs with correct arrows? I can never figure out the correct direction of the CTs because they work either way lol. Either way with either firmwares though, self consume does not work at all.
 
Mattb4 said:
According to the manual Anti-reverse prevents sending power to grid. So you would not enable it . However to setup your CTS and zero export is hard to figure out from a quick read of the manual. (Grid power percent?). Hopefully someone with more familiarity can chime in or you may need to consult your hybrid supplier.
Click to expand...
With this inverter "enable" means "enable grid disable". Bass ackwards
 
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