Shade effect on series panels.
Pictured below is the shading on 2 of 6 series-connected panels: And this is what the controller says: So, 57.2 x 5.6 = 320w (IN) Normal (full sun) should be about 84 x 7.5 = 630w,...
Forum Discussion
CA Traveler wrote:
A prior poster suggested you have Vmp = 14V. Nope - if that were the case the panels would not bulk charge a 12V battery when they are in a parallel configuration.
The panels are 36 cells or about 18V.
I simply divided the displayed Vmp by the number of panels, which were all supposed to be in the sun at the time. In series you add the voltages. 84.8/6 = 14.13
Panel rated Vmp at 77F is not to be confused with any actual Vmp at any one time in a particular circumstance for lighting etc.
I don't have my old notes and can't remember, so the question on that is, "When in lower or indirect light in the morning when the batts are still low, so the controller is in Bulk (and so MPPTing) and the panels are not at full voltage or their max currents, what Vmp will the controller choose?"
I have a record from a test when the batts were nearly full on 24v batts, and Vmp was rising from 29ish to 31ish. So Vmp does vary, but I don't know by how much it can vary. It seems to go up with battery SOC to some extent.
