Solar system for to supplement grid design - Am I thinking correctly

[Y2KINDYZ]

Ok new to solar, but I do know about a little about electricity, generators, inverters and batteries.

Ok here are my thoughts and plans. Need to know if I am on the right track or is my thinking way off.

I am in the process of building a small 1800 sq ft home with a barn. barn and home will be separated by about 100 ft. I ordered 3 EG4 inverters with 6 EG4 life power batteries and 40 475 watt bi-facial panels. My plan is to have all equipment in the barn. I want to have 2 strings of 8 panels for 2 of the EG4 to have 240 v. This I want to feed a sub panel in the house and run all loads except the A/C. A/C heater, Water heater, dryer and stove will run on gas. The 2 EG4 will use 5 batteries. I also want a mini split in the master bedroom in an off grid situation.

The third EG4 will be fed by the last 8 panels and use 1 battery. With this single EG4 will run some lights in the barn and a 120v AC unit to keep a 15‘ x 20‘ storage room cool inside the barn.
I want to have transfer switch for the sub-panels to be able to switch to and from grid. Grid will also feed the inverters if needed in the evening if needed.
I want to have the ability to go off grid if needed but use solar as much as possible.

Is my thinking logical or am I way off?

thanks in advance,

oscar

 

[Texican]

Think about running a grid AC wire to the barn, maybe 125 amp to a sub panel in the barn
then use the sub panel to provide AC input to the inverters in the barn
I would order another inverter and run them all 4 together for 240v
keep all 6 batteries together also
using another sub panel for the inverter AC output will allow you to get the 120v in the barn

this design is very much like mine except I have only 2 inverters

also having 1 system will make monitoring much easier

 

[Y2KINDYZ]

Think about running a grid AC wire to the barn, maybe 125 amp to a sub panel in the barn
then use the sub panel to provide AC input to the inverters in the barn
I would order another inverter and run them all 4 together for 240v
keep all 6 batteries together also
using another sub panel for the inverter AC output will allow you to get the 120v in the barn

this design is very much like mine except I have only 2 inverters

also having 1 system will make monitoring much easier

Hello Texican,
Are you from Texas?
Yes, both the house and the barn will have grid power. I may order another EG4 in the future, but it is just out of my budget at the moment.

I made a diagram of the Layout for the electrical. Please take a look and see if I am going about it correctly. Because of my budget, I was only able to get 3 EG4's, so I was thinking of keeping the single EG4 separate system for our room in the barn just to run that off-grid.

On another note, I had 2 panels arrive damaged and I just received an email with my options. I have the option of getting a credit or replacing the panels. Now that you told me about adding a 4th EG4, I just may be able to add it for the difference in my credit. I would have 38 panels vs 40, but that may be a good trade-off.
Thanks in advance,

Oscar

 

[Texican]

good diagram, yes I am in NE Texas

what part of the country are you in ?

I still dont like the idea of setting up as 2 systems.

if you do 1 system you can also get rid of the barn 30 amp sub panel
there will be lots of months where maybe you dont need to run the hvac in the barn storage rm, and then that 6th battery could be helping your house

depending on your loads in the house, you might be able to just run 2 inverters, up to 60 amps to the house.

if you run 4 inverters you will need to up your wire size from barn back to house to handle 120 amps as well as the sub panel in the barn

with 4 inverters you are open to add more solar panels later if you want

the HVAC in the house is what type & size ?
the hvac unit for the barn is what type & size ?

look into Solar Assistant to provide monitoring of your system

 

[Texican]

here is a pic of my system this is all in my workshop 100 ft from house

the AC in comes thru the left most conduit up from the floor. In the small junction box below the gutter and transfer switch I used morris split connectors to double each of the 4 wires. Then 1 set of AC input wires goes to the transfer switch and the other set goes to AC input on the inverters.
The AC output from the inverters goes to the transfer switch.

The transfer switch decides which power will go to the 125amp panel, located to the right of the transfer switch, which has the 60amp breaker going to the house panel

I did it like this so I could add some off grid outlets in the workshop at a later time

The middle conduit goin to the floor is the AC from the 60amp breaker going to the house

the conduit on the right is the incoming PV wires going to DC breakers before the inverters

 

[Y2KINDYZ]

good diagram, yes I am in NE Texas

what part of the country are you in ?

I still dont like the idea of setting up as 2 systems.

if you do 1 system you can also get rid of the barn 30 amp sub panel
there will be lots of months where maybe you dont need to run the hvac in the barn storage rm, and then that 6th battery could be helping your house

depending on your loads in the house, you might be able to just run 2 inverters, up to 60 amps to the house.

if you run 4 inverters you will need to up your wire size from barn back to house to handle 120 amps as well as the sub panel in the barn

with 4 inverters you are open to add more solar panels later if you want

the HVAC in the house is what type & size ?
the hvac unit for the barn is what type & size ?

look into Solar Assistant to provide monitoring of your system

The HVAC in the house will be a 3.5 ton and the barn will have an apartment area about 1500sqft that will have a 18,000BTU mini split but will be used sparingly. Within the apartment I plan to have a 200 sqft food storage room where I wanted to have the 110v 9,000 BTU mini-split as a stand-alone setup. But I guess I can do that if I run all 4 EG4's. Do you think it is over kill for what I want to run?

BTW, I am in the Rio Grande Valley area.

 

[Texican]

we have a 1600 sf house with propane stove and dryer. the electric water heater was left on the grid.

we also have a 200 sq ft outbuilding for food storage. with a 15000 btu window unit, It is on the grid
during summer we set the A/C to about 75

we also have a 14x30 workshop where all the solar system lives, and also 5 rescue stray cats it has a 2 ton window unit we set at 72 in summer. This building is on the grid

we have 2 grid tie systems totaling 11kw and
the off grid system is 12kw with 30kwh batts (6xeg4)

the house is off grid except for water heater and the 60 amp limit has never been an issue
for hvac we have 2 mini splits 2 ton each. we try to only run 1 at a time when possible

even if you do not replace the 2 broken panels, you have a lot of panels.
batteries will be your limiting factor
on a decent day your panels will charge up your batts quickly and then will power your house and all the rest of the potential power will not be created/used.

I would try to come up with a way to manually transfer some of your 3.5 ton hvac to the off grid system during the day or maybe even put it on the off grid system

with our 2 mini splits, at first I only put the bedroom one on the off grid, then we charged the batts quickly and wasted potential power. So in mid june we added the second mini split to off grid. now we produced all possible power all day. there were many days this summer when I has to put the house on SUB mode in the evening to use the grid for about 2 hours as I wanted the batts to be about 80 % when I went to bed at 10pm

its better to fully load the system even if sometimes the grid needs to help, than put too little on it, have it slow production after charging the batts and then by paying the grid to power the hvac

the basic structure of your system is the inverters and wiring. I would probably set up all 4 inverters with appropriate wire sizes.
more batts or pv panels can always be added later

 

[Y2KINDYZ]

Thank you. I was also thinking of having a small mini split for the bedroom for potential SHTF situation when no grid power is available. I know that will make wife happy if that were to ever happen like 2021. I think if I have all 4 EG4's I should easily go full off grid mode and have grid power to charge batteries at night if needed. I need to talk to my builder and see how to go about setting up a way to transfer AC load to and from solar. Or maybe have a main transfer switch and then run a separate circuit to send power to the inverters to charge batteries when needed.

Thanks

 

[Texican]

these inverters have various modes avbl
you can put everything on the off grid system and tell it to auto switch to the grid when batts are at a certain percent. I have mine set at 20 percent
main reason some people, including me have a transfer switch is just to take the inverters off line for maint and still power the house

 

[Y2KINDYZ]

That sounds like what I want to do. I need to download the manual and give it look over. Thanks again

 

[Y2KINDYZ]

here is a pic of my system this is all in my workshop 100 ft from house

the AC in comes thru the left most conduit up from the floor. In the small junction box below the gutter and transfer switch I used morris split connectors to double each of the 4 wires. Then 1 set of AC input wires goes to the transfer switch and the other set goes to AC input on the inverters.
The AC output from the inverters goes to the transfer switch.

The transfer switch decides which power will go to the 125amp panel, located to the right of the transfer switch, which has the 60amp breaker going to the house panel

I did it like this so I could add some off grid outlets in the workshop at a later time

The middle conduit goin to the floor is the AC from the 60amp breaker going to the house

the conduit on the right is the incoming PV wires going to DC breakers before the invertersView attachment 122419

Is your system tied to the grid?

 

[Texican]

Is your system tied to the grid?

yes it is. I use grid when ever needed to supplement the solar and batts

 

[Y2KINDYZ]

yes it is. I use grid when ever needed to supplement the solar and batts

Hello Texican,
hope all is well with you in the new year. Looks like we are finally going to start on our build of our home and barn. I decided to follow your advice and ended up getting another EG4, to make it 4 to have more total capacity and 1 system. Do you think having 4 EG4’s 6500w be enough to run both the house and barn off grid? I plan to run gas stove, water heater and dryer so the only major appliance will be the AC 3.5 ton in the house and 2 Or 3 (1-2 ton) mini splits in the Barn. Mini-splits will not be for primary cooling, only 1 small one for food storage room in barn (running 24/7). Other mini-splits will be for food prep area in barn and in house bedroom as a backup to keep central unit off in a true grid down scenario.

I plan to have solar equipment in the barn, but I am not sure if the electric company will bring power into the house or the barn. Does it matter if the power comes into the house vs the barn? I know I need to talk to my builder and meet with the electrician but wanted to get your thoughts since you have a similar setup. Thanks in advance

 

[Texican]

Good Morning
glad to hear about your 4th inverter. yes I think that will be plenty of power for you.
I would suggest that you have the power co bring the grid with a 200 amp panel to your house vs the barn, and then you run a 125 amp setup yourself from house to barn.

 

[Y2KINDYZ]

Good morning,
How do I get the solar power back to the house? Will I need a Transfer switch? I have 2 100amp Transfer switches available or I can get larger if needed. I modified my layout. Does it look about right?



Another thought I had was to run the Power from the Inverters from the barn back to a Transfer switch at the house, and have the transfer switch run everything. Only down side is the House central air would run on solar too, but I guess I could add another transfer switch for the AC.

Thanks for your help and advice

 

[Texican]

I think this would work for you and simplify things a bit.
no need for a trans sw at the house

 

[Y2KINDYZ]

I think this would work for you and simplify things a bit.
no need for a trans sw at the house
View attachment 128204

Cool. That does simply things. I will talk to my builder and electrition. Do you think 125Amp is enough to run the house and barn? Thanks again

 

[12VoltInstalls]

Need to know if I am on the right track or is my thinking way off. I am in the process of building a small 1800 sq ft home

Enjoyed your thread.

As far as the question about your thinking being off: 1800sf is not a small home?

 

[Y2KINDYZ]

Enjoyed your thread.

As far as the question about your thinking being off: 1800sf is not a small home?

Hey there 12V. We are currently living in a 3400sq ft home so we are down sizing. so in comparison it is a small home. 1800 sq ft is the min size for the town we are moving to. We would have preferred smaller. Lol I guess everything is bigger in Texas

 

[12VoltInstalls]

1800 sq ft is the min size for the town we are moving to. We would have preferred smaller. Lol I guess everything is bigger in Texas

Probably because that’s a tick bigger than the typical home that arrives on wheels I’m suspecting