Maybe a silly question, but can someone help me walk through what the potential panel degradation and hotspot concerns might be with an offset stack of bifacial panels on a vehicle roof? I'm planning to do a double stack of panels with drawer slides to extend at least one (possibly both) panel(s) out beyond the width of the vehicle. If I offset the top panel relative to the other I can use shorter drawer slides to expose both panels to full sun (30" vs. 36") and cover the full the width of the vehicle in the stowed position (better for aero).
The downside is that while the top panel will always be in full sun, the bottom panel will have ~10" (15% of its length) exposed at all times. The panels are half cut, and the exposed portion is along the short side of the array. I'm estimating 2 rows of cells will be in full sun, and a third will have partial.
I'm wondering if the bifaciality and transparency of the top panel will help the "problem". With a bit of light transmission through the top panel, the cells that are in "shade" might still get some harvestable light? OTOH, the mixture of full sun and shaded cells in the offset condition might be worse than if the panels weren't offset and all the cells of the lower panel were seeing similar light conditions.
The simplest way to find out would be to test the panels in the two conditions with power measurement and thermal imaging. I'd like to work out the theoretical solution prior to making any purchases though.
The downside is that while the top panel will always be in full sun, the bottom panel will have ~10" (15% of its length) exposed at all times. The panels are half cut, and the exposed portion is along the short side of the array. I'm estimating 2 rows of cells will be in full sun, and a third will have partial.
I'm wondering if the bifaciality and transparency of the top panel will help the "problem". With a bit of light transmission through the top panel, the cells that are in "shade" might still get some harvestable light? OTOH, the mixture of full sun and shaded cells in the offset condition might be worse than if the panels weren't offset and all the cells of the lower panel were seeing similar light conditions.
The simplest way to find out would be to test the panels in the two conditions with power measurement and thermal imaging. I'd like to work out the theoretical solution prior to making any purchases though.
