The ornamental design for a solar fandevice, as shown and described.
FIG. 1 is a front perspective view of a solar fan device showing my new design;
FIG. 2 is a front elevational view thereof;
FIG. 3 is a rear elevational view thereof;
FIG. 4 is a left side elevational view thereof;
FIG. 5 is a right side elevational view thereof;
FIG. 6 is a top plan view thereof;
FIG. 7 is a bottom plan view thereof;
FIG. 8 is a front perspective view thereof, the handle depicted by means of broken lines being for illustrating a working position of the handle; and,
FIG. 9 is a front perspective view thereof, the solar fan device depicted by means of broken lines being for illustrating a lying down position of the solar fan device.