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Can I Be My Own Grid?

A

Adlans

New Member
Joined
Apr 24, 2024
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7
Location
Texas
I currently have a grid tied enphase system on my home. Approximately 10kw of panels and 20kwh of battery backup. Any excess generation goes back to the grid.
On my garage I am installing 2 eg4 18 kpv controllers, 30 390watt Canadian solar panels and 3 banks of 6 eg4ll batteries for approximately 90kwh of battery backup. I will be adding more batteries as money becomes available. I am wondering if I can use my garage system as my “grid”?
Can I run power from the garage to the main disconnect of my home and shut off the utility company? I’m concerned about the enphase system trying to sell back to the “grid” at this point. Should I run power from the garage to a subpanel on the house and just take off some loads from the enphase system and put them on the garage system OR run wiring from the garage to the generator input on the enphase system?
 
what size is your grid tied inverter?... if its larger than your normal home load then sooner or later you will be forcing power backwards into the batteries.

some offgrid inverters allow this with phase adjustments phase controlled A/C coupling. IE they sense power going back into the battery due to overload on their output lines and then adjust the phase this causes the grid tie inverters to lower output while they try to adjust to the phase. I know the Magnum PAE offer this not sure about other makers.
 
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Since you already have an Enphase system with Enphase batteries?, its a proprietary system, not sure its going to mix well with an EG4 in a conventional AC coupling fashion. You may be better off exploring the upgrade option to Enphase IQ8 microinverters which will form their own grid, there is an additional Enphase anti-slanding device that needs to be installed. This will automatically disconnect the main panel from the grid when power goes out.
 
Daddy Tanuki said:
what size is your grid tied inverter?... if its larger than your normal home load then sooner or later you will be forcing power backwards into the batteries.

some offgrid inverters allow this with phase adjustments phase controlled A/C coupling. IE they sense power going back into the battery due to overload on their output lines and then adjust the phase this causes the grid tie inverters to lower output while they try to adjust to the phase. I know the Magnum PAE offer this not sure about other makers.
Click to expand...
The inverter is the Enphase EP200G101 with an electrical rating of 120/240vac, 200A at 60hz. I have 2 enphase IQ 10t batteries capable of 3.84kw output power for 7.68kva.
I have 30 365w solar panels each with the IQ7 inverter.
In the garage, I currently only have 1 18Kpv tied into a 60a do breaker in a 200amp load center I have 11700 watts of Canadian solar panels tied into the 18Kpv. I have a bank of 6 eg4ll batteries tied into the 18Kpv.
I will be adding another 18kpv tied in parallel with the other and two more banks of 6 eg4ll batteries.
What I want is for my house system (enphase) to pull extra needed energy from my garage system (eg4).
I’m thinking my best option is to pull a set of wires to a sub panel on the house and take some of the load hogs off the house panel and run them into the seperate sub panel.
OR could I run some wires to the meter panel The Grid and disconnect The Grid and run the house off a breaker from the eg4 system
 
BentleyJ said:
Since you already have an Enphase system with Enphase batteries?, it’s a proprietary system, not sure it’s going to mix well with an EG4 in a conventional AC coupling fashion. You may be better off exploring the upgrade option to Enphase IQ8 microinverters which will form their own grid, there is an additional Enphase anti-slanding device that needs to be installed. This will automatically disconnect the main panel from the grid when power goes out.
Click to expand...
Enphase equipment is very expensive and I can get a lot more bang for my buck with eg4 stuff. I don’t necessarily want to integrate the two systems together, I just want to pull any extra needed load from the EG4 system and not the grid.
I don’t know if I’m doing a good job of explaining my situation but thank you for lending a hand!
 
Adlans said:
Enphase equipment is very expensive and I can get a lot more bang for my buck with eg4 stuff. I don’t necessarily want to integrate the two systems together, I just want to pull any extra needed load from the EG4 system and not the grid.
Click to expand...
If the new EG4 system is set up in the garage with a new breaker panel and run as an independent system then that will work. You can even run utility power from the main panel at the house into the AC Input of the 18kpv. This is OK because if the grid goes out the 18kpv will disconnect from the grid and the 2 systems will be isolated from each other. When the grid is active the 18kpv can be set up to self consumption only and/or could theoretically export to the grid as well since 2 UL1741 compliant systems can be connected together.

Since the Enphase system has a battery and its own control system, I don't believe the Enphase system can be AC coupled with the 18kpv via the Gen Input or load side. Perhaps if the Grid Code on the Enphase was changed? Not sure, would recommend against this approach.

You would be better off installing a subpanel at the house and taking some loads off the Enphase system as mentioned above.
 
Let me guess you already bought all the stuff for this EG4 set up and now you’re figuring out how to make the two systems play together?
 
740GLE said:
Let me guess you already bought all the stuff for this EG4 set up and now you’re figuring out how to make the two systems play together?
Click to expand...
That is correct, at first I planned to operate the garage independently and add more battery to the enphase system. Then I realized how much more capability I could get by going the eg4 route. If I could go back to square one and had eg4 been available when I started, that’s the direction I would have taken. Or something similar.
 
BentleyJ said:
If the new EG4 system is set up in the garage with a new breaker panel and run as an independent system then that will work. You can even run utility power from the main panel at the house into the AC Input of the 18kpv. This is OK because if the grid goes out the 18kpv will disconnect from the grid and the 2 systems will be isolated from each other. When the grid is active the 18kpv can be set up to self consumption only and/or could theoretically export to the grid as well since 2 UL1741 compliant systems can be connected together.

Since the Enphase system has a battery and its own control system, I don't believe the Enphase system can be AC coupled with the 18kpv via the Gen Input or load side. Perhaps if the Grid Code on the Enphase was changed? Not sure, would recommend against this approach.

You would be better off installing a subpanel at the house and taking some loads off the Enphase system as mentioned above.
Click to expand...
My ultimate goal is to be completely independent of the grid. The eg4 is not and will not be grid tied. I’m not concerned about cutting my electric bill, I want to be completely energy independent. I truly appreciate all the input and must admit my knowledge is pretty elementary of most of the language being used.
 
It can work, but will take some tweaking for everything to cooperate together.
I think that the best way to do it would be to separate the enphase system from the house. Connect the enphase to the gen port of the 18kpv. And the house to the load port. (Along with the garage)
Then, a lot of tweaking settings on both, to get everything playing the way you want them to.
Another option would be to put the enphase system ahead of the 18kpv (grid port). And turn off the grid input to the enphase system. So that it only runs in "grid down" mode.
And again, tweaking the settings to operate as you want.
 
Adlans said:
Can I run power from the garage to the main disconnect of my home and shut off the utility company?
Click to expand...
That is the first thing you need to find out. Once you are connected, there are laws preventing you from disconnecting.
 
sunsurfer said:
That is the first thing you need to find out. Once you are connected, there are laws preventing you from disconnecting.
Click to expand...

sunsurfer said:
That is the first thing you need to find out. Once you are connected, there are laws preventing you from disconnecting.
Click to expand...
I currently live on 14 acres in the Texas Hill Country. My meter loop is on a utility pole about 100ft from the house. There is a 200amp breaker just below the meter that I can shut off and disconnect from the grid. I have done it before with the utility companies knowledge and there were no issues. The garage with the eg4 system is a metal building detached from the home by about 5 feet.
 
timselectric said:
There is a distinct difference between

And
Click to expand...
To clarify, the meter is about 100 ft from the home and has a 200amp breaker. I’m using two separate terms to say I’m gonna turn off the 200amp breaker and disconnect from the grid.
I apologize for being confusing
 
Adlans said:
To clarify, the meter is about 100 ft from the home and has a 200amp breaker. I’m using two separate terms to say I’m gonna turn off the 200amp breaker and disconnect from the grid.
I apologize for being confusing
Click to expand...
Yes, I understood that you meant that you were going to turn off your grid feed.
And not actually disconnect from the grid. (Have the power company remove it)
 
timselectric said:
It can work, but will take some tweaking for everything to cooperate together.
I think that the best way to do it would be to separate the enphase system from the house. Connect the enphase to the gen port of the 18kpv. And the house to the load port. (Along with the garage)
Then, a lot of tweaking settings on both, to get everything playing the way you want them to.
Another option would be to put the enphase system ahead of the 18kpv (grid port). And turn off the grid input to the enphase system. So that it only runs in "grid down" mode.
And again, tweaking the settings to operate as you want.
Click to expand...

Doesn’t the enphase need a grid signal to turn on back feed?

The gen port of the EG4 is also looking for a grid single, or does it generate its own?

Also the EG4 from the gen port will only pull what it needs, but the enphase pushes an unlimited amount PV dependent, some unique closed loop communication between the two would be needed.
 
740GLE said:
Doesn’t the enphase need a grid signal to turn on back feed?
Click to expand...
Yes
740GLE said:
The gen port of the EG4 is also looking for a grid single, or does it generate its own?
Click to expand...
Yes
740GLE said:
Also the EG4 from the gen port will only pull what it needs, but the enphase pushes an unlimited amount PV dependent, some unique closed loop communication between the two would be needed.
Click to expand...
Frequency shift is the only control.
No communication. (Other than RSD)
 
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