The ornamental design for a foldablesolarpanel, as shown and described.
FIG. 1 is a perspective view of a foldable solar panel showing our new design;
FIG. 2 is a front view thereof;
FIG. 3 is a top view thereof;
FIG. 4 is a right side view thereof;
FIG. 5 is a left side view thereof;
FIG. 6 is a rear view thereof;
FIG. 7 is a bottom view thereof; and,
FIG. 8 is an enlarged sectional view taken along line 8-8 in FIG. 2.
The dash-dash broken lines showing portions of the foldable solar panel are for the purpose of illustrating environmental structure and form no part of the claimed design. The dot-dash broken lines represent the boundary of the claimed design and form no part of the claimed design.