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Off Grid Install: Paralleling 2X EG4 18k's

Steve R

New Member
Joined
Jul 24, 2023
Messages
11
Location
Riverside
Hello,

Im in Riverside County, CA and in the process of building a 3600sq.ft home. I just received the tentative bill from so-cal Edison and they want $28k to pull wire (assuming I share the pole tap). That's not including all the trenching, pull boxes, and conduit that I would have to install. Im not looking for sympathy, rather, an off grid solution to bypass edison. Since the cost is so high and the distance to the pole is so far (1200ft), the county will review/ consider an off grid install.

Equipment: I have a 400a, solar ready panel and im looking to install the following -- 2x EG4 18k Inverters; 20x 450W panels (another 20x to follow later); 6x Eg4-LL bats (another 6x batts to follow later); and a 20kw Kohler backup gen. The problem im having is it seems that almost every discussion and video pertains to grid-tied solutions or older inverter systems that don't have all the integrated functionality of the new EG4 18k so it is difficult to assess what is needed (i.e., will the PV breaker on the inverter suffice for a kill switch or will county code make me put an external one as well)...do I tie the gen into one inverter or terminal block into both...

To my question: what is the best way to connect the 2x inverters, 20x panels (2 strings of 10), single battery bank (6x batts), and back up gen to the solar ready 400a panel? Please don't say "connect the inverters to the panel" and "connect the battery bank to the inverter"...The biggest problem that im having is that no one actually shows how systems are wired together AND into the breaker panel.

PS: im not an electrician but semi-intelligent and able to size the system and make the appropriate calculations. Please excuse my ignorance as im trying to learn without making a catastrophic mistake.
 
I did but it doesn't have a diagram for the 2x 18k off grid setup--thanks for stating the obvious though. Yeah, i figured if someone couldn't figure out what an EG4 18k Inverter is then i probably wouldn't need there help--thanks again for stating the obvious though.
 
I did but it doesn't have a diagram for the 2x 18k off grid setup--thanks for stating the obvious though. Yeah, i figured if someone couldn't figure out what an EG4 18k Inverter is then i probably wouldn't need there help--thanks again for stating the obvious though.
That's the confusion. It's not an 18k inverter.
Don't blame me. I didn't name it. lol
 
If it's going to be off grid why are you looking at the eg4 12k?
 
I'd push for using PV2 on each inverter with 12 panels apiece. I would add an IMO isolation switch before the inverter for the PV.

I would put a single 400A class-T fuse for the 48V bus and tap that with 4/0 to each inverter. (4/0 to the battery cabinet as well.) Eventually you will want the second cabinet and that gets a little more compliciated...but easy to modify.

As for the connection to your PV-ready panel, for off-grid it is as easy as "connect to the main" with the 18kPV.
 
Hello,

Im in Riverside County, CA and in the process of building a 3600sq.ft home. I just received the tentative bill from so-cal Edison and they want $28k to pull wire (assuming I share the pole tap). That's not including all the trenching, pull boxes, and conduit that I would have to install. Im not looking for sympathy, rather, an off grid solution to bypass edison. Since the cost is so high and the distance to the pole is so far (1200ft), the county will review/ consider an off grid install.

Equipment: I have a 400a, solar ready panel and im looking to install the following -- 2x EG4 18k Inverters; 20x 450W panels (another 20x to follow later); 6x Eg4-LL bats (another 6x batts to follow later); and a 20kw Kohler backup gen. The problem im having is it seems that almost every discussion and video pertains to grid-tied solutions or older inverter systems that don't have all the integrated functionality of the new EG4 18k so it is difficult to assess what is needed (i.e., will the PV breaker on the inverter suffice for a kill switch or will county code make me put an external one as well)...do I tie the gen into one inverter or terminal block into both...

To my question: what is the best way to connect the 2x inverters, 20x panels (2 strings of 10), single battery bank (6x batts), and back up gen to the solar ready 400a panel? Please don't say "connect the inverters to the panel" and "connect the battery bank to the inverter"...The biggest problem that im having is that no one actually shows how systems are wired together AND into the breaker panel.

PS: im not an electrician but semi-intelligent and able to size the system and make the appropriate calculations. Please excuse my ignorance as im trying to learn without making a catastrophic mistake.

The manual shows these two diagrams. Unfortunately, they don’t also list a diagram for parallel and off grid, but hopefully this at least provides some type of help.
I downloaded the luxpower manual as well as it’s the same inverter and couldn’t even find the off grid schematic at all

IMG_8819.jpegIMG_8820.jpeg
 
The only difference between grid-tied and off grid is the grid input. So that should be easy. But I am surprised that there isn't a diagram for parallel configuration.
 
The only difference between grid-tied and off grid is the grid input. So that should be easy. But I am surprised that there isn't a diagram for parallel configuration.
They do show stacked inverters with feeders, just don’t spell it out for stacked offgrid.
I had to laugh react your PV comment, one thing no one can accuse you of is being inconsistent ?
 
They do show stacked inverters with feeders, just don’t spell it out for stacked offgrid.
I had to laugh react your PV comment, one thing no one can accuse you of is being inconsistent ?
Oh , stacked is stacked. Just ignore the grid inputs.
As far as the name. I didn't name it. I just try to keep the confusion down for others reading.
 
Tim want's a couple of them real bad, he's just trying to talk himself out of buying them :ROFLMAO:
I wouldn't mind playing with one. But I don't really have a place for it, permanently. Actually, I don't really have the time to play with it. lol
 
I'd push for using PV2 on each inverter with 12 panels apiece. I would add an IMO isolation switch before the inverter for the PV.

I would put a single 400A class-T fuse for the 48V bus and tap that with 4/0 to each inverter. (4/0 to the battery cabinet as well.) Eventually you will want the second cabinet and that gets a little more compliciated...but easy to modify.

As for the connection to your PV-ready panel, for off-grid it is as easy as "connect to the main" with the 18kPV.
Agreed and once im permitted for the 20 then I will definitely add more PV lines later; however, i dont know about pushing more than 10 panels at 49 VOC as that is already 500VDC. Do i need the 400A fuse for the 48V bus if both inverters are breakered? I agree it is easy to connect to the main for 1 inverter but wouldnt i need an AC bus for the 2x inverters to the breaker panel?
 
The manual shows these two diagrams. Unfortunately, they don’t also list a diagram for parallel and off grid, but hopefully this at least provides some type of help.
I downloaded the luxpower manual as well as it’s the same inverter and couldn’t even find the off grid schematic at all

View attachment 159201View attachment 159202
Yeah, thats my problem. Off grid diagrams seem to favor 1x inverter setups which isnt helping my 2x questions...
 
Stacking 2 of these seemed easier than 4 lower rated ones. Also, heaven forbid we need to connect to edison later on.
You could stack two victron 10ks for less money and have surge capacity that's outta this world.

Also battery hookup has a 71kwh battery setup for $8800. With bms it's less than $10k. Not plug and play but needs minimal work

Give serious thought to minisplits. Ducted or ductless. No surge to speak of and very efficient. Also very diy friendly
 
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