caesarv
New Member
I have 2 strings of 6 panels each (Longi LR5; no optimizers or micro-inverters.) One string is in full sun while the other gets partial shade in the morning due to my neighbor's tree. When all are in full sunlight, each string produces about 3kW. However, when that one string is partially shaded over two or more panels, I get less than 100W from the entire string. I had assumed the bypass diodes would just eliminate the power from the shaded panels, leaving the rest intact. Apparently I was wrong.
In full sunshine, I can cover any ONE panel, and sure enough, the wattage drops by one panel's worth (~500W.) This proves the bypass diodes are working. However, when I partially cover two (or more) panels, the entire string drops to near zero. I was not expecting this. This severely impacts my morning solar production.
I am assuming that the MPPT in my 18Kpv can deal with one panel being bypassed, but when two or more are partially shaded, it's algorithm cannot find a suitable setting to deal with the combination. Does this make sense? Would adding optimizers on the two or three partially shaded panels help? Any other ideas?
Meanwhile, I will be trimming my neighbor's tree to minimize the shading (he is okay with this), but this will not completely eliminate the morning shading.
In full sunshine, I can cover any ONE panel, and sure enough, the wattage drops by one panel's worth (~500W.) This proves the bypass diodes are working. However, when I partially cover two (or more) panels, the entire string drops to near zero. I was not expecting this. This severely impacts my morning solar production.
I am assuming that the MPPT in my 18Kpv can deal with one panel being bypassed, but when two or more are partially shaded, it's algorithm cannot find a suitable setting to deal with the combination. Does this make sense? Would adding optimizers on the two or three partially shaded panels help? Any other ideas?
Meanwhile, I will be trimming my neighbor's tree to minimize the shading (he is okay with this), but this will not completely eliminate the morning shading.