It won't be any problem for 18 degree angle cleaning. Concerning traversing between solat panels, it depends on the height of the frame edges and the gap between panels. Basically, as soon as WS-600 hits the frame edge, it may change direction. However, if the frame edge height is so low or the gap between panels is so small until no suction pressure loss to Icleanrobot then it will traverse to other panels.
You can wash all washable smooth surface. Including horizontal and angled window. We tested the robot on the ceiling, and it also worked fine. But you should keep in mind that cleaning the ceiling does not provide instruction manual.
Note that if the surface relief, the force of gravity of the robot is reduced.
You most likely will need to change the cleaning cloth pads over time, however they are washable and reusable. There are 2 extra ones that are included in the original box. You do not need to use cleaning fluid, but if you would like, you can.
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