How to you do to size correctly a PWM controller nominal current ?
Thanks
asked
PWM controller
Panel Isc (short circuit current) must not exceed PWM controllers rated current.
To be safe, give 20% margin.
Panel Impp should be lower than Panel Isc. If you exceed the Amps, it will likely damage your PWM.
and exemple I have a solar panel with Immp=8.29A and Isc=8.89A
Can I use a PWM of 10A?
for me no because : Icontroller = 1.25*8.29=10,69A is more than the 10A of rated current.
Am I right or can I accept? Or my formule of calculation is wrong?
PS:Sorry for my bad english
THANKS
If you want to be safe, no. You have a 25% Margin in your calculation...
Don't use Impp for calculations, use Isc.
Nothing to be sorry for, I can understand you perfectly.
Regards,
Markus
So if I use Icontroller=1.25*Isc=1.25*8.89=11,11A
So the good controller to choose is the PWM 20A.
Right or false?
Another question the 25% is save or what is the save one?
Thanks
Yes, you got it right.
You can even add more panels in future with the 20A, if you want.
The common practice is to use 25%, to be safe under all circumstances.
If you are not sure, on what this safety depends on, just use 25%.
Regards,
Markus
Thanks Markus if I add another pv of 150W the current will be now 22,22A which is more than the controller rated current ( 20A).
