how to wire 5 24v panels

MichaelK

Photon Sorcerer
Your top first diagram shows 8.6 amps going through the 2 in // (edit: the original panel with the spare in //)
This should be 4.3 amps though each // pv When you have this the V across the 2 in // will rise and the V across the series will rise the same. The increase will be somewhere between Voc & Vamp depending on the PV's properties. Even though you still have the same current going through the series, it is at the slightly higher voltage. Thus wattage has increased.
These statements are not correct. Remember the addage, in series voltage adds while amperage stays the same. In parallel, amperage adds while voltage stays the same. So, two 8.6A panels wired in series is NOT 4.3A + 4.3A. It just stays at 8.6A.

In terms of voltage the Vmp and the Voc would both be exactly double what a single panel would be. There will be NO averaging of the Voc & Vmp.
 

Bud Martin

Photon Sorcerer
Where will the current go!
Only the label says 8.6A which is more or less correct for the single panel but not now for the // 2.
What do you mean by 'Where will the current go'? Panels are power source, the load will draw current from the power source.

Series and parallel:
 

MichaelK

Photon Sorcerer
Where will the current go!
Only the label says 8.6A which is more or less correct for the single panel but not now for the // 2.
You don't seem to understand the basics of electrical mechanics. In series voltage adds while amperage stays the same. In parallel, amperage adds while voltage stays the same. I'm not a theoretical physicist, so I can't explain why in more detail.

For one 2-panel string of panels in series, the Voc would be 38.6Voc + 38.6Voc =77.2Voc at 8.6A. That's because in series voltage adds while amperage stays the same.

For one 2-panel string of panels in series, the Vmp would be 31.4Vmp + 31.4Vmp = 62.8Vmp at 8.6A, as for the same reason as mentioned in the sentence above.

When you have two parallel strings of 2 panels in series at 62.8Vmp, the amperage will be 8.6A + 8.6A = 17.2A at 62.8Vmp, because in parallel, amperage adds while voltage stays the same.

Keep in mind though that in the real-world both the voltage and amperage will flutuate depending on daily conditions. The voltage the panels put out will go up as the temperature goes down. The amperage will go down when the intensity of the sun goes down. So, the numbers are really a rough guide to what you should expect to see.
 

snoobler

Solar Honey Badger
Your top first diagram shows 8.6 amps going through the 2 in // (edit: the original panel with the spare in //)
This should be 4.3 amps though each // pv When you have this the V across the 2 in // will rise and the V across the series will rise the same. The increase will be somewhere between Voc & Vamp depending on the PV's properties. Even though you still have the same current going through the series, it is at the slightly higher voltage. Thus wattage has increased.

Even if what you say is true, and I won't believe it is until I see test data that demonstrates it, the voltage of the 2P+1S string must be the same as the 2S string. Any increase in the voltage of the 2P+1S string would make the 2S string run at LOWER current thus DECREASING the power of the 2S string.
 

sunshine

Solar Addict
Even if what you say is true, and I won't believe it is until I see test data that demonstrates it,
I will be able to do that on Sunday.
the voltage of the 2P+1S string must be the same as the 2S string. Any increase in the voltage of the 2P+1S string would make the 2S string run at LOWER current thus DECREASING the power of the 2S string.
You need to look at the mppt graph. Add a extra panel ,1P to 2P, will increase the voltage if load is the same to a V back up the mppt graph or you can keep the same V if you double the load.

2P to 3P will also increase V, but because the graph is exponential there is less V increase than the 1P to 2P....there is only a 10v difference between Voc and Vmax so a infinite number of panels in P wont go up above the Voc at that original Vmax load.

Because we are only using that 10v difference between Vmax and Voc and is mainly obtained by that first additional panel the benefits fade out in longer strings.

I have a 32P string!
 
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richard cabesa

Solar Enthusiast
Even if what you say is true, and I won't believe it is until I see test data that demonstrates it, the voltage of the 2P+1S string must be the same as the 2S string. Any increase in the voltage of the 2P+1S string would make the 2S string run at LOWER current thus DECREASING the power of the 2S string.
I’m new here and learning, so excuse my thickness

what the heck is 1S?
If there is only one, what is in series?

Seriously
 
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MichaelK

Photon Sorcerer
I’m new here and learning, so excuse my thickness

what the heck is 1S?
If there is only one, what is in series?

Ser
Today solar panels are commonly wired in various combinations of series and parallel to meet specific voltage or amperage requirements. The typical convention used today to illustrate a wiring scheme is the xSxP designation, which describes how many parallel strings of panels in series you are using. So, if for example you had six panels wired into two parallel strings of three panels in series, you would write 3S2P.

If somebody simply wants to keep with the contemporary convention and report that they have five panels in parallel, they could write 1S5P. It's just the shorthand that keeps it simple for the majority.
 

richard cabesa

Solar Enthusiast
Today solar panels are commonly wired in various combinations of series and parallel to meet specific voltage or amperage requirements. The typical convention used today to illustrate a wiring scheme is the xSxP designation, which describes how many parallel strings of panels in series you are using. So, if for example you had six panels wired into two parallel strings of three panels in series, you would write 3S2P.

If somebody simply wants to keep with the contemporary convention and report that they have five panels in parallel, they could write 1S5P. It's just the shorthand that keeps it simple for the majority.
I get the shorthand and I have three systems running. As I said, I’m thick. I would really love a picture of what 1S would be.
Crayon is fine
 

richard cabesa

Solar Enthusiast
Today solar panels are commonly wired in various combinations of series and parallel to meet specific voltage or amperage requirements. The typical convention used today to illustrate a wiring scheme is the xSxP designation, which describes how many parallel strings of panels in series you are using. So, if for example you had six panels wired into two parallel strings of three panels in series, you would write 3S2P.

If somebody simply wants to keep with the contemporary convention and report that they have five panels in parallel, they could write 1S5P. It's just the shorthand that keeps it simple for the majority.
I guess it is sinking in a bit for me. The 1S is just to describe that you only have one string of five.
but if it is to be shorthand, in your example, wouldn’t 5P be shorter?
 

snoobler

Solar Honey Badger
I’m new here and learning, so excuse my thickness

what the heck is 1S?
If there is only one, what is in series?

Seriously

It was intended to represent the unconventional proposal to add a panel in parallel with ONE panel in a 2S array.

See post #19:


That sounds like extraordinarily poor design!

Or an Electrodacus array.
 

sunshine

Solar Addict
That sounds like extraordinarily poor design!
It is what happens when you start using the 120w panel/pwm at home between the camping trips and keep adding panels while preferring the benefits of a low voltage system.
With solarPV it would have been better if Edison had won the war of the currents!
 

sunshine

Solar Addict
I would really love a picture of what 1S would be.
I am in a gang of one!!

1S is also probably more appropriate than using 1P because it acknowledges the cells in series within the panel.
My 1S is 32 cells in series (1/2 the panel) for 20V in a 12V system that is 13.2V standing.
 

sunshine

Solar Addict
I eagerly await your detailed test data
Yesterday was too overcast. In between clouds today managed to get enough readings.

Panels are ZNShine Solar 190w 44.85voc 5.15a @31.1v These have been halved for 12v system. Using 3 of these 1/2 sections.
2S A+ .....-B+......-C The spare off & on between B+.... -C

Load is 2 12v 50w halogen globes in series that are close to matching the panels , Between A & C

2S readings are A 27.1v 4.3a C A 14.0v 4.3a B B 13.0v 4.3a C

2S plus spare readings are A 30.0v 4.6a C A 12.2v 4.6a B B 17.7v 2.3a C
B 17.7v 2.3a C

The readings were consistently the same spread and the globes visibly brightened with the spare attached
 

snoobler

Solar Honey Badger
Yesterday was too overcast. In between clouds today managed to get enough readings.

Panels are ZNShine Solar 190w 44.85voc 5.15a @31.1v These have been halved for 12v system. Using 3 of these 1/2 sections.
2S A+ .....-B+......-C The spare off & on between B+.... -C

Please dumb this down. It may make perfect sense to you, but I'm lost. I can kinda piece it together from what follows below, but I'm missing something.

Load is 2 12v 50w halogen globes in series that are close to matching the panels , Between A & C

The above is plain enough assuming the operational voltage of the series bulbs is ~24V.

2S readings are A 27.1v 4.3a C A 14.0v 4.3a B B 13.0v 4.3a C

2S plus spare readings are A 30.0v 4.6a C A 12.2v 4.6a B B 17.7v 2.3a C
B 17.7v 2.3a C

The readings were consistently the same spread and the globes visibly brightened with the spare attached

You haven't tested your proposed configuration. Your proposed configuration was to have the 2S(2P+1S) in parallel with another 2S on an MPPT controller.

You've tested two independent single string arrays with a resistor and removed the interaction between the parallel strings.
 

sunshine

Solar Addict
You haven't tested your proposed configuration. Your proposed configuration was to have the 2S(2P+1S) in parallel with another 2S on an MPPT controller.
The result will be relatively the same. I used one side, for simplification, to show that adding one panel in parallel to another in a string of 2 does increase power output.

I'll test the extra 2S in // tomorrow, weather permitting, with another 2 50w bulbs added in // to the 2 present. This will represent a mppt at that load
 

sunshine

Solar Addict
Result of adding the extra 2 panels in // and increasing the load with the extra 2 50w globes in series.

4 panels in 2 series = 25.1v 8.22a

with the 5th spare panel added in // with one of the above panels 26.6v 8.44a
 
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