Are there any benefits to running a 3s4p arrey instead of a 6s2p?

JamesHird · Feb 9, 2022

I picked up my 12x250v solar panels from Santan solar the other day, nice operation they've got down there.

While I was there the lady I was dealing with suggested setting my arrey up in a 3s4p configuration. When I asked why she couldn't give me an answer, just that this is what they would usually do.

I was planning on running 6 panels in 2 parallel strands. Does anyone know which way of doing it is best for me?

I've got the Growatt 48v 5k inverter/charge controller. It's rated to 450VDC. The panels are 37.6V so 225.6V for the 6p2s set up, well within range.

Thanks in advance,

James

chrisski · Feb 9, 2022

More panels in parallel protects against shading, but the cost is more amps and less votls for the same Load which means thicker wire or more voltage loss. Also, depending on your solar charge controller, 6S could exceed the voltage The SCC is rated for, especially when cold.

Since MC4 cables are limited to 10 AWG, wiring thicker than that on panels is hard fora string. Strings can be put in a combiner box and then the wiring made thicker.

I have an RV, so shading is something I need to deal with. If your panels have no shading, than 6S2P could be easier if your SCC can handle the voltage. I ended up with 3 SCCs and all of those have panels set in series parallel.

Regardless, doing the math is important.

JamesHird · Feb 9, 2022

chrisski said:
More panels in parallel protects against shading, but the cost is more amps and less votls for the same Load which means thicker wire or more voltage loss. Also, depending on your solar charge controller, 6S could exceed the voltage The SCC is rated for, especially when cold.

Since MC4 cables are limited to 10 AWG, wiring thicker than that on panels is hard fora string. Strings can be put in a combiner box and then the wiring made thicker.

I have an RV, so shading is something I need to deal with. If your panels have no shading, than 6S2P could be easier if your SCC can handle the voltage. I ended up with 3 SCCs and all of those have panels set in series parallel.

Regardless, doing the math is important.

Well within voltage for my SCC 450VDC so shouldn't be a problem there.

All the panels should get unhindered sun from dawn till dusk so shouldn't be a problem with shading ether.

I guess if I had a shading issue then it would make sense to do it.

James

12VoltInstalls · Feb 9, 2022

JamesHird said:
was planning on running 6 panels in 2 parallel strands. Does anyone know which way of doing it is best for me?

6S2P is what I’d do in your circumstance.

With no shading you have ideal sun. In that case I ‘might’ experiment with facing one array S and the other six panels SW. But if your batteries are fully charged to sunset that may do nothing for you.

JamesHird · Feb 9, 2022

I was tempted to do 3s4p, have 3 panels facing SE, 6 panels S and 3 SW. This would help me out as I don't have much battery capacity at the moment. (Only 1 48v, 100ah) Doing this set up would broaden my optimal solar window.

I do intend on getting more batteries though, when I can afford it. It would be easier to build a rack similar to the one in the link below apart from with round wood. Close the walls in, insulate it and I've got a decent sized solar shed plus storage.

Redirect Notice

time2roll · Feb 9, 2022

+1 for 6s2p

Just be careful with 200+ vdc

MisterSandals · Feb 10, 2022

JamesHird said:
I was tempted to do 3s4p, have 3 panels facing SE, 6 panels S and 3 SW. This would help me out as I don't have much battery capacity at the moment. (Only 1 48v, 100ah) Doing this set up would broaden my optimal solar window.

Spreading the arrays is a good strategy for limited battery but you would want the parallel strings to be equal. 3S + 6S + 3S will not work.

4 panels SE, 4 S, 4 SW works. (4S3P)
6 SE, 6 SW is easiest. (6S2P)
Which produces more, i dunno.

You would need to fuse each of the strings when connecting 3 or more in parallel.

Jordi · Feb 10, 2022

Here a clear example of how a parallel configuration is more resilient to shadowing

solar panels in series with different currents

But as you mention, most likely not necessary in your case.

Perhaps you can also play with the panels position either vertical or horizontal to reduce the effect of sunrise and sunset.

time2roll · Feb 10, 2022

Jordi said:
Here a clear example of how a parallel configuration is more resilient to shadowing

But as you mention, most likely not necessary in your case.

Perhaps you can also play with the panels position either vertical or horizontal to reduce the effect of sunrise and sunset.

The bypass diodes seem to have failed on the series string.

JamesHird · Feb 10, 2022

Thanks for the replies.

I just got to the land my wife and I purchased. It's fully Forrest so going to start clearing land for the homestead and solar panels over the next few weeks. It will become apparent if I need to put them in more strings or not. Shouldn't do though because I'm planning on clearing a square acre and putting the panels centered on the south boundary.

Exciting times..

chrisski · Feb 10, 2022

JamesHird said:
Thanks for the replies.

I just got to the land my wife and I purchased. It's fully Forrest so going to start clearing land for the homestead and solar panels over the next few weeks. It will become apparent if I need to put them in more strings or not. Shouldn't do though because I'm planning on clearing a square acre and putting the panels centered on the south boundary.

Exciting times..

If you are in the Northern Hemisphere, the panels may be better Placed on the Northern Boundary.

Sounds like you’re living the dream.

JamesHird · Feb 10, 2022

chrisski said:
If you are in the Northern Hemisphere, the panels may be better Placed on the Northern Boundary.

Sounds like you’re living the dream.

I meant northern boundary. Haha

It's the start of a dream, very early stages yet. I'll post pics of my solar endeavors.

I'm a total rookie when it comes to solar so it's a big learning curve

Are there any benefits to running a 3s4p arrey instead of a 6s2p?

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