Inverter wiring question

[JOELANCASTER]

Hi,

we are trying to build a system with raw material we have on hand (ground mounts, used solar panels, and 1200ft of 350 single strand copper wire). We are pretty new to this and we are seeking ideas. It's a 65kw, 450v, and 150amps to a 120/240 volt split phase house. The plan is to go off-grid. The solar panel arrays are about 650 ft from the house and we have enough wire to run one pair to the house. Is it possible to use one source DC wire from panel to several inverters in the house?

Thanks for any input

[Ampster]

This is the same question as your other post. Do you want the Mods to move that discussion here with the replies for continuity? Are you no longer considering an off grid system?

Your options are limited by the constraint of only having enough wire to run two of them 650 feet. The cost of digging a trench is going to be a lot more than the cost of running two additional wires in conduit. Even if you are digging it yourself that two wires constraint still limits the available options for inverters versus running 240 volts AC from the ground mount array to the house. Multiple 10 kW inverters at the ground mount array have got to be less expensive and easier than finding a single inverter that can handle that amount of DC power. I think that opinion was expressed in the other thread.

[bcroe]

The cost of digging a trench is going to be a lot more than the cost of running two additional wires in conduit.

On that I must disagree. Here between buildings the wire was the over riding
expense. The trench was free, since I had a cheap trencher. Running copper
could have cost me many thousands of $, I dodged that cost and that of conduit,
with direct burial aluminum wire. Bruce Roe

[Ampster]

On that I must disagree. Here between buildings the wire was the over riding expense. The trench was free, since I had a cheap trencher. Running copper could have cost me many thousands of $, I dodged that cost and that of conduit, with direct burial aluminum wire. Bruce Roe

Haha, I was thinking of your example when I wrote that response. Of course if you have a trencher and/or do the work yourself the dynamics would change.The OP already has the copper wire but could sell that1200 feet and buy enough aluminum direct burial wire for a 240 Split phase sub panel at the ground mount site. That would be like your installation and would be optimum.

[DanS26]

Wow....no mention of voltage drop. Running 3 wire of high voltage DC will be much less expensive than 4 wire of low voltage AC.


Put the inverters at the house.

[Ampster]

Wow....no mention of voltage drop. Running 3 wire of high voltage DC will be much less expensive than 4 wire of low voltage AC.


Put the inverters at the house.

Got any suggestion for a 65kW inverter? He has 65kW of panels. Even a 50 kW would work with the wire he has plus he will have to buy 650 ft of ground wire.

[DanS26]

Got any suggestion for a 65kW inverter? He has 65kW of panels. Even a 50 kW would work with the wire he has plus he will have to buy 650 ft of ground wire.

Well, it seems most 65kw inverters are 480v AC

[JOELANCASTER]

This is the same question as your other post. Do you want the Mods to move that discussion here with the replies for continuity? Are you no longer considering an off grid system?

Your options are limited by the constraint of only having enough wire to run two of them 650 feet. The cost of digging a trench is going to be a lot more than the cost of running two additional wires in conduit. Even if you are digging it yourself that two wires constraint still limits the available options for inverters versus running 240 volts AC from the ground mount array to the house. Multiple 10 kW inverters at the ground mount array have got to be less expensive and easier than finding a single inverter that can handle that amount of DC power. I think that opinion was expressed in the other thread.

Hi Ampster,

This will be an off-grid system eventually. I agree with Bruce R. that wiring will cost 10x the cost of digging the trench (we have the equipments). I am not sure I like the idea having un-secured equipments plus heated/cool space. I do appreciate your suggestion and keep that in mind. If you can move the thread here, it would be great. Thanks

[JOELANCASTER]

On that I must disagree. Here between buildings the wire was the over riding
expense. The trench was free, since I had a cheap trencher. Running copper
could have cost me many thousands of $, I dodged that cost and that of conduit,
with direct burial aluminum wire. Bruce Roe

I agree since it's not just an additional pair. We have 4 arrays and that means 3 more pair of copper wires.

[JOELANCASTER]

Got any suggestion for a 65kW inverter? He has 65kW of panels. Even a 50 kW would work with the wire he has plus he will have to buy 650 ft of ground wire.

We are looking for used cheap conduit to keep the cost down but a 50kW should work because of possible shading.

[Mike 134]

We are looking for used cheap conduit to keep the cost down but a 50kW should work because of possible shading.

use PVC and bury it per code.

[bcroe]

Some lengths like this, 4/0-4/0-4/0 Triplex Aluminum Direct Burial Wire
search on Evil Bay, could be cheaper and no conduit. Other sizes
available. Needs to be 2 gauges heavier to match copper losses, and
termination equipment must properly handle aluminum. In use here for
a couple years, boosted my efficiency nearly 3% for minimum $.
Bruce Roe

[Ampster]

I don't know much about price and availability for large inverters but if I had that large of an array 600 feet away from my home I would want to cost out small inverters at the array versus a large inverter at the home including the different wiring schemes. Implicit would be an analysis of wire loss as mentioned by DanS26 .

[DanS26]

Some inverters are more or less sensitive to voltage loss and can operate in a wider range. Some are even field adjustable to be outside their stated range....just saying. It might be well advised to analyze the inverter specs closely before purchase which ever route you go.

[JOELANCASTER]

Some lengths like this, 4/0-4/0-4/0 Triplex Aluminum Direct Burial Wire
search on Evil Bay, could be cheaper and no conduit. Other sizes
available. Needs to be 2 gauges heavier to match copper losses, and
termination equipment must properly handle aluminum. In use here for
a couple years, boosted my efficiency nearly 3% for minimum $.
Bruce Roe

Thank you for this recommendation. It definitely an option for us.