I haven't been able to properly test my Soprays but one is different from the other in low light.
Maybe low light variation is just a characteristic of mono crystal panels.
It is characteristic of all panels.
Of the identical pairs of panels I tested, amorphous was the worst, and so bad I didn't go into much testing because they were not suitable for what I was trying to do. To be fair, I am not sure if one of the amorphous PVs had exponentially more hours in the sun than the other.
Small polys were what I did the most testing on.
The surprising thing to me was how they were so different under different conditions.
The higher output panel in great sun may be the lower output panel with some very slight overcast.
The higher output panel at 12.2V may be the lower output panel at 14.4V.
The higher output panel when aimed straight at the sun may be the lower output panel with a few degrees of misalignment.
I suggest testing them all in decent sun for proper operation, then forget about it...
Or buy that 5 gallon bucket of Tylenol at Sam's Club before you get into the detailed testing.
G-