Photovoltaic PV connection ???

[chris34]

Hello,
I currently have 12 panels from 80 Wc connected on 2 strings. 1 string of 4 Pv, 1 string of 8 PV, both bound to its own regulator.
In short, I want to reorganize all with a single string and regulator (bigger) to my pool of batteries in 24 V.
Is there a formula that allows to connect the 12 PV (in series, serie parralléle, etc ...)
80 Wc pv data: Voc = 21.6, Isc = 4.88, Vmpp = 18, Impp = 4.44
Pool of 4 12 V / 90 Ah batteries, connected in series / parallel
(24 V / 180 Ah)

Thanks in advance !!! O)

[elephant]

Yes, but the important thing is to know the controller / charger data to see which configuration suits it, including its operating voltage range.

The ideal is also to have the complete data sheet of the panels to calculate their maximum winter and minimum summer tension.

[Remundo]

in fact, nothing can be said to you without knowing the voltage input range of the controller, as well as its maximum allowable current.

We can estimate the max tension at cold in winter even if you do not have the data. it is not a fundamental thing.

[chris34]

Thanks thanks ,

I misspoke !!!!!!
In fact I would also like to know which regulator to place, so obviously I do not know its characteristics because, I hope you give them to me !!!

thank you ...

[Remundo]

Well, it's simple, dear Chris,

you are looking for solar charge controllers for these 24V battery packs, for a power of the order of 1000 W (since 12 panels x 80Wc = 960 W)

Look a bit wide, maybe 800 to 1200 W.

look for the technical characteristics each time: input voltage range and max.

Then we will tell you how to organize your panels (series, parallel or more probably: mixed).

[elephant]

+ 1,

when Raymond says "look", he says: look for data sheets.
as for me I would rather establish the range between 1000 and 1200 watts

[chris34]

Hello !

hummm ... I found at Victron a range not bad:
BlueSolar MPPT 100 / 15 - 12 / 24 V 15 Amp
BlueSolar MPPT 100 / 30 - 12 / 24 V 30 Amp
BlueSolar MPPT 75 / 50 - 12 / 24 V 50 Amp
BlueSolar MPPT 100 / 50 - 12 / 24 V 50 Amp

there, I admit that I have trouble making my choice ...

[Gaston]

Hello !

hummm ... I found at Victron a range not bad:
BlueSolar MPPT 100 / 15 - 12 / 24 V 15 Amp
BlueSolar MPPT 100 / 30 - 12 / 24 V 30 Amp
BlueSolar MPPT 75 / 50 - 12 / 24 V 50 Amp
BlueSolar MPPT 100 / 50 - 12 / 24 V 50 Amp

there, I admit that I have trouble making my choice ...

Well, your panels can each provide at most 21,6V, a total of 259,2V if put in series.

With a controller that accepts up to 100V at the input (the three BlueSolar MPPT 100 / xx), it will be necessary to cut the string into 3 segments, ie 86,4V at most.
The maximum current supplied by the 3 segments in parallel will then be 3 * 4,88 = 14,64A. The regulator 100 / 15 will be a bit limited, I would take the regulator 100 / 30.

If on the other hand one cuts the chain in 4 segments, each one will supply 64,8V and one will have at most 4 * 4,88 = 19,52A. The 75 / 50 controller can also be used in this configuration.

It remains to be seen what is most practical given the location of your panels (3 chains of 4 panels or 4 chains of 3 panels).

Note: the lower the voltage used, the greater the diameter of the cables used to limit the losses.

Attention: in both cases, the tension of the chains (86,4V or 64,8V) is deadly if we touch the contacts

[chris34]

Thank you Gaston !!
your explanation is LIMPIDE
In fact I currently have 2 strings (with 6 mm² cables) feeding small regul. Pwm, I could do, if I followed you well:

1) a String of 12 PV, consisting of 3 segments of 4 PV in series, all connected to a regul. 100 / 30

2) 2 strings of 6 PV each, each consisting of 2 segments of 3 PV in series, each of the 2 strings feeding a regul. 100 / 15

[Gaston]

1) a String of 12 PV, consisting of 3 segments of 4 PV in series, all connected to a regul. 100 / 30

Yes.

2) 2 strings of 6 PV each, each consisting of 2 segments of 3 PV in series, each of the 2 strings feeding a regul. 100 / 15

Yes. (An 75 / 15 regulator would be sufficient if it exists).


The choice between one or two regulators is not simple:

• 1 single MPPT regulator for several sets in parallel does not get the best of the MPPT if the sets do not have exactly the same sunshine (orientation, shadow, ...)
• several regulators are more efficient for the MPPT, but it must be verified that there will be no conflict between them at the battery.