I don't know how much heat can be transferred thru the rubber roof or how the panels will be affected
but I read some specs that said full output with surface temps of 180*F
and a you tube video where a man tested one by laying it on his padio deck in the sun and had full output into his battery
my problem has been to find more unisolar panels so I would have matching voltages and charging characteristics
I do not feel like removing everything and starting over with higher wattage higher voltage panels (that produce more watts per sq inch) and new controller
my unisolar will produce power even during overcast or rainy weather,
it takes a really bad day to get no output from them
even here in the winter lying flat on the roof they produce something until sunset
at 5:20 pm dusk sun on horizon the will produce 500ma into almost fully charged batteries
the two (possibly bad) old OEM panels are not uniSolar
Saturday produced 843.7 watt hrs, avg charging rates almost 10amps, peak amps at 11.83
and this was with a bad connection from two of the old panels
Sundays results were just a hair lower but I was on the roof working and interfering with the solar distribution (shading as I moved around)