Portable power supply

FIG. 1 is a front elevational view of a portable power supply showing our new design;

FIG. 2 is a rear elevational view thereof;

FIG. 3 is a left side view thereof;

FIG. 4 is a right side view thereof;

FIG. 5 is a top plan view thereof;

FIG. 6 is a bottom plan view thereof;

FIG. 7 is a perspective view thereof;

FIG. 8 is a second perspective view thereof; and,

FIG. 9 is a third perspective view thereof in an open configuration.

Portions of the portable power supply illustrated by broken lines do not form part of the claimed design.