Might see some lift at highway speeds but I have my doubts that it will be much of anything. The air passes over the panels level since the roof extends another ~4 feet. Heck, it might actually create the opposite effect and suction the panels to the roof. It will be interesting to see what happens.
The fifth panel remains unused. We bought a batch of five because the cost of four was more. We may or may not take it with us (kind of big and bulky). For our current smallish battery bank (24V 125AH) I am starting to think 1080 watts will be plenty.
As for the height and clearance (roger Roger), we wanted to keep the overall rig height as low as possible. Since we don't have roof stuff, like A/C or vents, it made sense to have the panels low (they are about 1 inch off the roof. It *has* to be better to have that one inch of air rather than directly sticking a panel to the roof, like the Unisolar (which we did consider).
