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EG4 18KPV off grid being feed from another Inverter on the AC mains

AlaskaStartsHere

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Alaska
I am planning on installing a large ground mount array over 400 feet away from my EG4 18KPV. Instead of running multiple long runs of PV wire, I was wondering if I could just buy a split phase inverter, install it at the array and bring the 240VAC output from the inverter into the Grid inputs on the 18K?

Is there any reason not to do this?

Is there a way to coordinate the output capability of the upstream inverter with the demand that the 18K will want, so that the 18K uses a combination of PV and battery when load exceeds the upstream capacity?

This might seem like more trouble than it's worth, but the PV wire will cost almost as much as an EG4 6000XP. It will free up the PV1/1 and 1/2 Inputs on my 18K, for additional smaller strings close to the house. It will allow me to power AC loads with shorter runs that are located closer to the ground mount.
 
Depending upon how you were going to configure those panels into strings, you in theory could be sending the DC back at 400+ some volts. AC would be at 240. So DC would require small gauge wire for the same losses...
 
I don't think you need special PV wire. THWN is normally rated for 600v. Assuming your string voltage is more than 240v, you should be able to use smaller wire (less amps). You still need the same protection (conduit).
 
I am planning on installing a large ground mount array over 400 feet away from my EG4 18KPV. Instead of running multiple long runs of PV wire, I was wondering if I could just buy a split phase inverter, install it at the array and bring the 240VAC output from the inverter into the Grid inputs on the 18K?
The feature update labelled 'Smart Gen Load' that will allow you to hook up even a existing grid tied system (without battery) to the GEN port of your inverter.
Is there a way to coordinate the output capability of the upstream inverter with the demand that the 18K will want, so that the 18K uses a combination of PV and battery when load exceeds the upstream capacity?

This might seem like more trouble than it's worth, but the PV wire will cost almost as much as an EG4 6000XP. It will free up the PV1/1 and 1/2 Inputs on my 18K, for additional smaller strings close to the house. It will allow me to power AC loads with shorter runs that are located closer to the ground mount.
Yes to all of that.

 
Should be able to connect it to the generator port. It should be able to be set with input limits.
I have a generator connected. I would want this on the mains connection. Also how would you limit the input if you don't know how much supply you will have at any given time?
 
The feature update labelled 'Smart Gen Load' that will allow you to hook up even a existing grid tied system (without battery) to the GEN port of your inverter.

Yes to all of that.

That's a bummer that I have to use the generator input, but awesome that it's all in there.

What upstream equipment is supported? Does it have to be another 18k?
 
You can AC couple onto the grid input of the 18K too, it's just not as flexible but would basically work.
But as also pointed out here, THHN is rated to 600 volts so it can carry your PV no problem, I kind of like spending the money on something simple and dumb and just do it once and do it right. x pairs of THHN plus a single ground in one or two PVC tubes or could you use direct burial UF in your area?
 
You can AC couple onto the grid input of the 18K too, it's just not as flexible but would basically work.
But as also pointed out here, THHN is rated to 600 volts so it can carry your PV no problem, I kind of like spending the money on something simple and dumb and just do it once and do it right. x pairs of THHN plus a single ground in one or two PVC tubes or could you use direct burial UF in your area?
The 8 gauge THHN is the same price as the PV wire. I was hoping to get something cheaper. I planned for 2 strings (double the amount of PV wire), or 1 run of 240v electrical wire. I am just looking for options, and trying to think outside the box. I don't have the exact distance, but it's probably around 400+ feet, so I am basing my price on 500' of wire.
 
You can use 10 AWG for MPPT 1 (25A max) for 2 parallel strings and 12AWG for the MPPT 2 and 3 (15A max) single strings.
I was looking at 8 gauge due to the distance, and concerned with voltage drop. My string will be over 500v, but power loss is still a consideration.
 
I have a generator connected. I would want this on the mains connection. Also how would you limit the input if you don't know how much supply you will have at any given time?
I think that your best option would be to move the generator to the grid port. And use a grid-tied inverter to AC couple to the generator port. Run PV DC from the array and place the grid-tied inverter close to the 18kpv. Voltage drop is not a huge concern for the PV. But it would be for the AC.
If your generator is not big enough, maybe use a charger between the generator and battery, instead of running through the 18kpv.
 
I was looking at 8 gauge due to the distance, and concerned with voltage drop. My string will be over 500v, but power loss is still a consideration.
I wouldn't be too concerned about voltage drop/power loss, the amount of time it will be running 100% power is tiny, a loss not worth considering perhaps.
Very rarely have I seen a nice bell power curve from my system, today it looks like an earthquake...go away stupid storm Debby.
 
I am planning on installing a large ground mount array over 400 feet away from my EG4 18KPV. Instead of running multiple long runs of PV wire, I was wondering if I could just buy a split phase inverter, install it at the array and bring the 240VAC output from the inverter into the Grid inputs on the 18K?

Is there any reason not to do this?

Is there a way to coordinate the output capability of the upstream inverter with the demand that the 18K will want, so that the 18K uses a combination of PV and battery when load exceeds the upstream capacity?

This might seem like more trouble than it's worth, but the PV wire will cost almost as much as an EG4 6000XP. It will free up the PV1/1 and 1/2 Inputs on my 18K, for additional smaller strings close to the house. It will allow me to power AC loads with shorter runs that are located closer to the ground mount.
400 feet of underground feeder cable of 2AWG would cost >$3000.00 (I just purchased 130 feet for $1500.00 in June.) It will handle 120A.

I had to bring the grid to my 18K.

Low amperage of 400 to 500 volt PV strings would be <20A. 10 AWG handles this beautifully. And much less expensive!
 

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