Does anyone know of a simple and cheap way of comparing different array orientations?
I have a fixed north-facing array, angled for winter sun. A second array is on the roof facing north, but since the roof has only a 7 degree pitch, it is almost facing straight up - i.e. summer orientation.
It is off-grid. The arrays are on separate, but networked, MPPT controllers. So it's all about battery charging. Bring the batteries to float as early as possible, and then hold them there as late as possible.
As an alternative to array tracking, I've been wondering about fixed east and west facing arrays, and other variations so I want to compare several orientations. I don't need to know anything in detail - just a comparison of light falling on each area at the same time.
What I have in mind is to use several small cheap PV cells, place 2 of them with the same orientation as the existing arrays, and others in the other potential locations. If I then log voltage from each cell it will give me an idea of how the possible orientations compare with the existing ones.
I've got a multi channel data logger I could use, but can anyone think of any other way of doing a comparison like this?