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diy solar

diy solar

My 9kw (soon to be 16,5kw) solar array with 3 inverters setup to generate 3 phase power

Hi i am very happy to present my system. Its up and working. Is my first solar project and i am not an electrician so there will be a lot of weird stuff at first look maybe :)
Anyway i want to thank to everybody here because i couldnt have made it without the wonderful information and support on this forum.
Ank me anything you want to know about it.
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I am guessing there is no inspections required?
 
I am guessing there is no inspections required?
Are you trying to imply that you can see something that obviously will not pass inspection? If that is the case let me know.

The inspections are required on certain conditions. In Italy is legal to diy your own solar system if is under 20 KWp and if you DO NOT feed power to the grid. Since 2021 you dont need a permit from your municipal government to do it, except in the case of areas of historical relevance where the conservation of aesthetics is a factor. The list of regulations for an off grid system is the CEI EN 62124. It specifies a list of general rules and tests for the system, like the need to use certified components for example, and is not hard to follow.
 
One thing that will obviously not pass inspection are the DC breakers.

For your safety...
Please change.
 
The biggest problem is that DC makes an arc, and the good breakers have an arc catcher
now.. the cheaper black ones (who still can cost quite some money)... that "arc catcher" is a childs toy.
and after an x amount of switches, it does get stuck, with continuous arc.
Yes this was the last issue to solve. I started a thread asking for alternatives and people recommended changing them for class T fuses.
The thing is that i am going to change the system and use my own diy lifepo4 battery bank. Every pack will have its own dc breaker, a much higher quality one. Here is a picture of the model (made of 3d printed parts and common hardware), the dc breaker highlighted in green.batterya.jpgbatteryb.jpg
 
Really good.

Your question was"
Are you trying to imply that you can see something that obviously will not pass inspection? If that is the case let me know "

It all looks really good and professional.
Except the breakers :-)
 
Are you trying to imply that you can see something that obviously will not pass inspection? If that is the case let me know.
Could be two dozen things that wouldn't pass inspection in US.
US and European approach are quite different in many cases, both having some weird parts.
 
Could be two dozen things that wouldn't pass inspection in US.
US and European approach are quite different in many cases, both having some weird parts.
For what i have read here these things also could change a lot depending on what state of the US we are talking about. Like in Florida diy lifepo4 battery banks being illegal. For Italy, as i have pointed out before, the normative reference for an off-grid system is the CEI EN 62124. It would not surpise me if this same normative extended to a big part of the European Union.
 
A little update of my system:

- My objective was: 1 day of complete sun without clouds when the temperature outside is lowest (these days -5 to -10 ºC) = 72hrs of normal electric usage + heating after sunset.

I have come very close to this, with 1 day of full sun these days of January i can go for 48-60 hours after sunset, depending mostly on the moisture of outside air.
It turns out that my 2xMitsubishi kirigamine zen that heat my apartment need to do a lot of defrosting and when its done they need to work harder to keep the temperature. This is worst when humidity is high.

The solution is very simple, take advantage of the very low prices right now to expand my system with +3,4kwp of panels and +30kwh of batteries.
I cant put more panels (legal limit for off grid systems in Italy is 20kwp)

And with a little more tweaks in the apartment insulation i will get there for sure. And to think that the solar companies i approached first with this idea in my mind told me that it was not possible... Live and learn!

I will post some more photos of things i am doing in the future, is kind of messy right now and i have very little time to work on it. ?
 
That looks amazing!

I'm upgrading my system a bit so if you don't mind I've got two questions for you about the MCCBs and the fuses on your battery setup (as this topic always messes with my head!)

On the right power bank, you've got the system set up so that the positive goes:
Busbar -> Fuse -> MCCB -> cells

Whereas on the left it goes:
Busbar -> MCCB -> Fuse -> cells

Did you intentionally move the fuse position between the 2 sides?
If so, what was the reason for that? (Does it even matter?)

The second one is about the MCCB itself.
I think I have the exact same model as you, and I'm curious about the orientation you're using.
I was under the impression that those MCCBs "worked" with power in both directions (in/out), however, they would only trip in an over-current/short circuit situation if the power flowed from top to bottom (top in, bottom out). Do you know if this is correct or not?

This goes back to the previous question, you've flipped the orientation of the MCCBs between the left and the right banks. If my theory (above) is correct then, if the battery has a short, the MCCB on the right should trip before the fuse blows, whereas on the left the fuse blows and the mccb does nothing. Where as if there is an issue with the power in (e.g. inverter goes nuts somehow), then it's the other way round.

*Btw, if I'm completely completely wrong, please tell me!
 
That looks amazing!

I'm upgrading my system a bit so if you don't mind I've got two questions for you about the MCCBs and the fuses on your battery setup (as this topic always messes with my head!)

On the right power bank, you've got the system set up so that the positive goes:
Busbar -> Fuse -> MCCB -> cells

Whereas on the left it goes:
Busbar -> MCCB -> Fuse -> cells

Did you intentionally move the fuse position between the 2 sides?
If so, what was the reason for that? (Does it even matter?)

The second one is about the MCCB itself.
I think I have the exact same model as you, and I'm curious about the orientation you're using.
I was under the impression that those MCCBs "worked" with power in both directions (in/out), however, they would only trip in an over-current/short circuit situation if the power flowed from top to bottom (top in, bottom out). Do you know if this is correct or not?

This goes back to the previous question, you've flipped the orientation of the MCCBs between the left and the right banks. If my theory (above) is correct then, if the battery has a short, the MCCB on the right should trip before the fuse blows, whereas on the left the fuse blows and the mccb does nothing. Where as if there is an issue with the power in (e.g. inverter goes nuts somehow), then it's the other way round.

*Btw, if I'm completely completely wrong, please tell me!
It all derives from me wanting to have short wires from the MCCB to the busbars, so i arranged to position them close to the center.
For what i understand they are bi-directional, meaning that if the charging or discharging current passes 160A they will trip, but they have a positive and a negative side that needs to be respected. As you can see all have the same orientation, having the positive side up and the negative side down.
As for the Tfuse the reason for it being on the other side on the left is because when i was 3d printing the grey brackets i forgot to 'mirror them'. The bracket that has the T fuse has a support so the wire doesnt come loose if the fuse breaks in half, also removing the stress that the thick wire puts on it. I should have mirrored the model before printing them so i can mount the fuses the other way around but after i thought it doesnt matter so i dont need to reprint them.
The Fuses are 175A so i dont expect them to trip before the MCCB, that has a limit of 160A. In this way i have 3 levels of protection, first the Bms that i have limited to 150A, then the MCCB at 160A and if they both fail then the Tfuse at 175A.
bracketsupport.jpg
 
Thank you for that explanation, and again, I really (really) like your setup!

Those MCCBs drive me nuts as they're somewhat of an unknown to me. I have asked the sellers and they've all been very fluffy with me. They all say "bidirectional" but I've also had one suggest that when they say bidirectional, they mean that it "works" but the overcurrent protection will only work in 1 direction. I really want to find a way (make something I guess) to test how those MCCBs work when hit with a short or a crazy high current.(I've been using mine with no issues for a while - charging and discharging so no worries there, I guess it's just an itch at the back of my head to know what protection it provides.)

Out of curiosity, have you considered either sharing or selling the STLs/model files for the 3D-printed components?
 
Thank you for that explanation, and again, I really (really) like your setup!

Those MCCBs drive me nuts as they're somewhat of an unknown to me. I have asked the sellers and they've all been very fluffy with me. They all say "bidirectional" but I've also had one suggest that when they say bidirectional, they mean that it "works" but the overcurrent protection will only work in 1 direction. I really want to find a way (make something I guess) to test how those MCCBs work when hit with a short or a crazy high current.(I've been using mine with no issues for a while - charging and discharging so no worries there, I guess it's just an itch at the back of my head to know what protection it provides.)

Out of curiosity, have you considered either sharing or selling the STLs/model files for the 3D-printed components?
Testing them could be an idea for a video for Will i guess.
In the resources tab there is a section for 3d printed files where i have added a couple of things, i will put them there for free if you want them.
 

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