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What are the wiring options when you have 10 panels? Series with different total voltages - do they play nice?

BigIslandRyan

BigIslandRyan

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Newb question; If I have 10 identical panels, each with open circuit voltage of 20volts. And I have a max 80volt all-in-one MPP inverter/controller.. what are my options for series/parralel of the panels? a series of 5 panels is too much voltage. A series of 4 is fine, and I can parallel two of those series, which is 8 panels. But what about the remaining two panels? Can I just run them in a series and "merge it" with the other 8 panels using Y connectors?
Can you do a 3S3P arrangement and still use the 10th panel? Idont understand how single panels can be added to the mix when they are at lower voltage? Can someone give me the simple explanation? I guess I'm asking about how do you join series when the series have different total voltage? Thanks.
 
BigIslandRyan said:
A series of 4 is fine, and I can parallel two of those series, which is 8 panels.
Click to expand...
A series of 4 is fine at 25 degrees C. If you get colder temps, they can produce more than Voc. My understanding is that ANY exceeding of voltage limits will "release" (fixed it) the magic smoke... YMMV.

You will need to reveal your Isc (short circuit amperage) of your panels for anybody to make any kind of recommendation about configuring an array, especially paralleling strings.
The max input amps of your SCC is also needed.
 
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MisterSandals said:
A series of 4 is fine at 25 degrees C. If you get colder temps, they can produce more than Voc. My understanding is that ANY exceeding of voltage limits will reduce the magic smoke... YMMV.

You will need to reveal your Isc (short circuit amperage) of your panels for anybody to make any kind of recommendation about configuring an array, especially paralleling strings.
The max input amps of your SCC is also needed.
Click to expand...

Thank you. The panels lsc is 5.7amps each and the max input amps is 80 amps. Its one of these: https://www.ebay.com/itm/2400w-24V-...y-charger-80A-MPPT-solar-charger/272998194866

Thanks for your feedback / help!
 
so many numbers LOL. I guess I was looking at the max charging current of 80amps. I'm not clear on the max input amps actually.
 
There is probably no max input in amps only max watts depending on your PV voltage. I would not run 4s I'm afraid you will have too many overvolt situations. Do 3s3p and save the headache of having SCC shut down or worse fry from too much power. You could possibly do 1 string of 4s with 2 strings of 3s b ecause the 3s strings paralleled with the 4s will hold the volts down (I think)
 
Craig said:
1 string of 4s with 2 strings of 3s b ecause the 3s strings paralleled with the 4s will hold the volts down (I think)
Click to expand...
What would the advantage be to having 4s+3s+3s over 3s+3s+3s? My understanding is that the voltage of the 4th panel in the strings always have voltage clipped by the 3s string present.

And, if the 3s strings get disconnected, there will be "too many over volt situations".
So is there ever an upside to 4s+3s+3s? Only a drastic downside, right?

I like your original thought, 3s3p.
 
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There are always things you can do with that 10th panel, such as power lights around your array so you can see it at night if ground, or landscape lighting, or as a spare should a projectile crash one of your panels. So, 3s3p, 1 spare that can optionally go to lower priority use with a cheap controller.

One guy put in a remote control actuator to tilt his array that he powered with an extra smaller panel and LED lights so he could see the position at night and different colors so he could verify the direction it was moving. Why remote control adjust it at night from your house? Because a wind storm is coming and you want to flatten it.
 
MisterSandals said:
What would the advantage be to having 4s+3s+3s over 3s+3s+3s? My understanding is that the voltage of the 4th panel in the strings always have voltage clipped by the 3s string present.

And, if the 3s strings get disconnected, there will be "too many over volt situations".
So is there ever an upside to 4s+3s+3s? Only a drastic downside, right?

I like your original thought, 3s3p.
Click to expand...
The voltage will actually average so he would get a little more power from that last panel. Good point though if other strings get disconnected.
 
Ahh yes,
MBR said:
That model has a Max PV Input Voc 145V so you could series 5 panels at 20 volts = 100V


View attachment 11182
Click to expand...

Ahh yes, you are correct, 145 volts in, so I guess 5S2P is my ideal setup. And i think the answer to having "extra panels" is that they will just "dumb down" the system (or average it) due to the lower voltage, so there's no point, huh? Or go 3S3P and find a use for the other panel around my house. Thanks for your input everyone!
 
BigIslandRyan said:
Ahh yes,


Ahh yes, you are correct, 145 volts in, so I guess 5S2P is my ideal setup. And i think the answer to having "extra panels" is that they will just "dumb down" the system (or average it) due to the lower voltage, so there's no point, huh? Or go 3S3P and find a use for the other panel around my house. Thanks for your input everyone!
Click to expand...
Having 10 vs 9 would still yield more power than 9 but the 10th or 4s string won't have as much power as a single 4s string more like a 3.5s string
 
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