What is the equilibrium temperature of a panel of black sheet metal hanging out at an orbit of 1 AU? Because if the thing is solar powered then it cannot exceed that temperature on average (ie across the entire mass) due to energy being conserved. You can do goofy things like using solar power coupled with a heating element (such as a GPU) to shift more heat to one part of the panel or another (ie employ an insufficient heat spreader design) but you fundamentally cannot exceed the equilibrium temperature on average.