The ornamental design for the portable solar power supply, as shown and described.
FIG. 1 is a perspective view of the portable solar power supply from the generator crank side, with the connection ring in the extended configuration;
FIG. 2 is a perspective view of the portable solar power supply with the connection ring in the housed configuration;
FIG. 3 is another perspective view of the portable solar power supply from one of the solar panel sides with the connection ring in the housed configuration;
FIG. 4 is yet another perspective view of the portable solar power supply from one of the solar panel sides with the connection ring in the extended configuration, showing all three solar panels;
FIG. 5 is a top plan view of the portable solar power supply with the connection ring in the extended configuration shown in environmental use.
FIG. 6 is a bottom plan view of the portable solar power supply of FIG. 2;
FIG. 7 is a side elevational view of the generator crank side; and,
FIG. 8 is a side elevational view of one of the solar panel sides.
The broken lines shown represent unclaimed subject matter and form no part of the claimed.