diy solar

diy solar

Help I'm an idiot

Nospmis

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May 9, 2022
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I am attempting to help someone who knows less than me set up a solar system that was sold to him. From what I understand, it's decent equipment.

(6) REC twin peak 2 mono series, pmpp 320w solar panels
(12) 12v 100ah agm batteries in series parallel (3 sets of 4 batteries in parallel(48v) in series)
(1) outback flex max 80
(1) 3000w 48v inverter

My original thought was to run the pannels in series parallel, 3 in parallel, 3 in parallel and then join together in series, but after researching, I am more confused then when I began. I know I'm probably over thinking it, but i am lost and don't want to fudge it up or start any fires. What would be the ideal way to set up the system? Any advice would be greatly appreciated. I will post a picture of my proposed wiring diagram shortly. My apologies in advance for being a moron. Take it easy on me!
 
Great so you were right to put 3 in series for 120Voc, well under 150V max.
You will need to fuse the 3 strings just before combining in parallel. There are inline MC4 fuses that are convenient.

I would be concerned about wiring so many batteries together to make sure its wired in a balanced manner.

Otherwise looks like a beefy system.
 
What is the max input voltage of the Flexmax 80?
What is the Voc of the panels?

The panels have to be arranged so a temp adjusted Voc of the array stays below the max input voltage.
Sorry I was still uploading the pictures. The voc for the pannels is 40v. Isc is 10.3. Max input voltage on flex max is 150 vdc if I'm reading it correctly (see pics) thankyou for the speedy reply Mr. Sandals.
 
I am attempting to help someone who knows less than me set up a solar system that was sold to him. From what I understand, it's decent equipment.

(6) REC twin peak 2 mono series, pmpp 320w solar panels
(12) 12v 100ah agm batteries in series parallel (3 sets of 4 batteries in parallel(48v) in series)
(1) outback flex max 80
(1) 3000w 48v inverter

My original thought was to run the pannels in series parallel, 3 in parallel, 3 in parallel and then join together in series, but after researching, I am more confused then when I began. I know I'm probably over thinking it, but i am lost and don't want to fudge it up or start any fires. What would be the ideal way to set up the system? Any advice would be greatly appreciated. I will post a picture of my proposed wiring diagram shortly. My apologies in advance for being a moron. Take it easy on me!
 

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Great so you were right to put 3 in series for 120Voc, well under 150V max.
You will need to fuse the 3 strings just before combining in parallel. There are inline MC4 fuses that are convenient.

I would be concerned about wiring so many batteries together to make sure its wired in a balanced manner.

Otherwise looks like a beefy system.
 
Ok I'll pick up some of the mc4 fuses. Now, when you say in a balanced manner, does my crayon drawn diagram look Ok? The charge controller is set up to balanced the batteries daily. Is that enough?
 
regarding battery wiring, this PDF has some useful info:

1652117339982.png

the way in the drawing may result in uneven load, someone please also double check
 
regarding battery wiring, this PDF has some useful info:

View attachment 93994

the way in the drawing may result in uneven load, someone please also double check
Oh I see. That makes sense now. The way I had it will draw from the ends compared to equally from each battery. Thankyou curious carbon! I will update drawing and post!
 
Wait, so with 6 panels, 3S2P you do not need fuses. Only 3P or more.

You originally said 3 series, 3 parallel but your diagram got me back on track.
I'm sorry, ya I ment 2 sets of 3. I'll probably fuse just for the heck of it.
 
the way in the drawing may result in uneven load, someone please also double check
Agreed, as drawn will be uneven. I do not know the best solution.

@Solarod seems to have thought about arranging batteries more than the rest of us combined. Maybe he can help with a solution.

His ideas and explanations are presented here (there is a calculation thread that backs this up too):

 
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Didn't read the post but saw the title. I'm just here to hang out with my fellow

The way drawn:
View attachment 94006

Potentially balanced "Diagonal" rewire:
View attachment 94007

if the second one is not actually balanced, someone please correct me and i'll edit this post ??️
Ok but wouldn't I want all the runs from bank to inverter and charge control to bank to be the same length right? Something like this? (See pic) sorry there's smoke coming out of my ears right now. Not an artist nor an eletrical engineer in the least bit.
 

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Ok but wouldn't I want all the runs from bank to inverter and charge control to bank to be the same length right?
Yes that's the right idea.

You might want to make a big positive bus bar and a big negative bus bar. Connect inverter, batteries, charge controller, to the bus bar (rather than connecting multiple wires at so many different points).
 
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