Hi,

I am interested in doing a quick and dirty measurement of the IV curve for a PV panel that I have. I have power resistors, power supplies, and electronic loads available. Let's assume that the ratings are what they ideally need to be for each so that's not an issue. I'm sure I can find what I need if I don't have it, I just need the general experiment setup and procedure.

I was originally thinking about simply measuring Voc and Isc for a given irradiance (that I would not know but should be able to calculate in the end. Using the electronic load, I could change the resistance value, the record the resistance and current supplied from the electronic load.

The same could be done with a actual resistors but the resolution would not be as fine.

I'm not quite sure how to get the characteristic resistance since the IV curve would be unknown. Maybe I could

1) measure Voc and Isc
2) calculate what the irrafiance should be based on Isc measurement from Step 1.
3) calculate fill factor based on data from datasheet.
4) calculate characteristic resistance at multiple points to build curve.
5) adjust electronic load to characteristic resistance calculates and record voltage/current at multiple values.

The problem that I see with this is the fill factor and datasheet info is at STC and NOCT which will not be my conditions.

Does anyone know a better way to get the IV curve or see any reason my proposed method will not work?

 

5) adjust electronic load to characteristic resistance calculates and record voltage/current at multiple values.

That's the way I'd do it, assuming I can trust the accuracy of the load. You can't solve the irradiance issue "internally". You'll need some sort of independent measure of irradiance if you care about how your panel responds.

Be aware that temperature will influence your panel output negatively, so be sure to monitor panel temperature - or at least ambient temperature - and record it along with your results.