Below a picture of the new MPPT calculator.
I’ve entered details from one of my installations, selecting the correct panel for which I have manufacturer data.
There are some discrepancies.
The VOC values for -10deg.C are correct in both locations.
For 60deg.C, in one place is correct, in another no.
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This are 2 different values.
PV min voltage at 60° Is the MINIMUM voltage, your system will encounter UNDER LOAD at maximum temperature.
String Voc is the MAXIMUM voltage, your system will encounter WITHOUT LOAD at maximum temperature.
If you adjust f.e. the cable length, you can see, that the MINIMUM voltage calculated drops, while the MAXIMUM voltage stays the same. (Because without load, cable length doesn’t cause voltage drops - but the difference is more than just cable length, in the first place it’s the difference between Voc and Vmpp at the given temperature)
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In that case, according with the manufacturer, Vmp on NMOT is 38.9V at 41deg.C, which, corrected with temperature, checks with 184.9V.
Minus cable drops, it’s OK.
Thanks!
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