Hello all,
I've had a look through the forum but I can't seem to find an answer.
I have four 50W Renogy panels which I used on a previous project (so they may have some damage/degradation). I originally had them connected as 2S2P to a 75/15MPPT and to a 24V SmartPack. I also have two Solbian 186W panels connected in series to the same battery via a separate 75/15MPPT controller.
The problem is that voltage on the output of the 2S2P Renogy is about 27V meaning I can't get the battery fully charged relying just on the Renogy panels. The Solbian panels are reading about 39V in the same location. Vmp of each panel is 18.5V and 19.6V for the Renogy and Solbian, so should be about the same?
I decided to change the panels to be 3S (disregarding the fourth panel) and the voltage is still the same 27V. I then swapped the controllers over to check if this was the issue and the Renogy remained at 27V and the Solbian still at 39V.
Any idea why the Renogy panels have a low voltage despite the same load and location as the Solbian panels? Are the panels/connections damaged? Is there a problem with having two types of panels connected via separate controllers?
Thanks for your help.
