Balkonkraftwerk wieviel Watt erzeugen zwei Module?
Hallo in die Runde,
ich habe nunmehr ein Balkonkraftwerk mit zwei Modulen, die an einen Micro inverter Gleichrichter 600 Watt angeschlossen sind.
Zwei Dinge, die mir auffallen
1.
Wenn ich nur ein Modul anschließe, werden mir in der App als Power 230 Watt angezeigt. Schließe ich beide Module an, werden mir nur 330 Watt angezeigt. Ich hätte erwartet, dass meine Anlage bei zwei Modulen 460 Watt erzeugen.
Ist also die geringere Ausbeute das Ergebnis eines Fehlers oder ist das pysikalisch eben so?
2.
Mein Gleichrichter schaltet sich immer mal wieder einfach aus. Jedenfalls leuchtet plötzlich die LED rot. Nach einiger Zeit blinkt die LED grün und bleibt dann auf Dauergrün. Manchmal bleibt das Gerät so einen ganzen Nachmittag, manchmal schaltet es sich aber auch wieder ab.
Gibt es dafür eine Erklärung, oder ist der Gleichrichtet defekt?
Vielen Dank fürs Durchlesen.
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1)
When connected in parallel, you have a big problem with efficiency.
The current that a module can generate depends on the voltage that the module has. The higher the voltage, the more difficult it becomes for the light to beat charges in the crystal lattice. This then also produces the theoretical limit for the efficiency of 50%. If it generates voltage, it also at the same time prevents it from generating current. But no current without voltage. Therefore, solar cells cannot exceed 50% efficiency for physical reasons. Real cells are currently around 20% because they are not “perfect”.
If two modules are now fitted in parallel, then the module inhibits the “more powerful” is the “lower” by so much more.
The cheap “snaps” are modules that work alone well, but strongly “from the row of dancing” and don’t work well together with other modules. They can’t be used for large plants and they are sold individually cheaper.
If two of them are connected in parallel, one does not get twice the power, even if they are perfectly aligned, i.e. equal to the sun.
And that’s the next problem. Different soiling and slightly different angles to the sun ensure that one of the modules can afford much less even if the modules are identical.
Therefore you turn them in series whenever possible. Here, however, it is necessary to check how high the maximum voltage is that of the controller or Inverter stops. Large installations then have X modules in series which can generate as much idling voltage as the inverter powered and then these series-connected groups are connected in parallel until the number of modules has been adapted to the roof.
So check the maximum voltage which both modules generate in series in no-load and see if the inverter carries it. Then you can turn them in series.
2)
This happens when the power of the modules is too small to operate the inverter. This is constantly changing through the time of day but also through clouds or “dunst” in the air. If the modules no longer supply enough voltage, the inverter starts. This is also improved by series connection since the voltage supplied is doubled. so the inverter can start early in the morning and run even longer in the evening, even disturbances due to clouds then have less effect.
P.S.:
When you look at the roofs, you often notice that they could have made a few more modules, so there’s room.
If the groups are, for example, 4 modules in series, then one must have 4, 8, 12, 16 etc. If, for example, 15 fit the roof, one can only connect 12 so then a gap for 3.
Thank you for the detailed information.
Nevertheless, I am still very uncertain.
I have four values in my app. Current (mA)
Power (W)
Voltage (V)
Total
and in the middle a stylized circle with value Today(KWh)
Under Power, if the sun shines, I will display a value of up to three digits and in the course of the day under Today(KWh) a value of 1.45 and 1.87.
I assume this is the size of my kilowatt hours, or am I wrong?
It is strange, however, that I reach 1,63 and 1.87 KWh with two connected panels in the top, but with only one connected panel on three days in each case 1,50 KWh. It doesn’t fit.
kWh are “kilowatt hours”. This is an energy that is 1000W for one hour or a watt for 1000 hours.
Power in W is the momentary power. It’ll be about time to energy. 333W would then turn into a kWh in three hours.
And, as I said, the panels do not work in parallel when they are different, i.e. production tolerance, alignment and degree of contamination.
It may also be that the inverter has the voltage that can supply too little to have full power.
You need to determine how high the maximum idling voltage of the panels is and whether the inverter then holds twice. Then you can turn it in series for maximum power efficiency.