How To Calculate The Torque Needed For Your Application
Torque exerted by the panel at any given angle is:
Torque = Weight Of Panel X Length From The Axis Of Rotation To The Center Of Gravity X Cosine Of The Angle
If the weight of the panel is evenly distributed, we can assume that the CG is in the center of the panel. In this case, the length from the axis of rotation to the center of gravity is equal to half the length of the panel.