The ornamental design for a mountedusbcharger, as shown and described.
FIG. 1 is a perspective view of a mounted USB charger showing my new design;
FIG. 2 is a front view thereof;
FIG. 3 is a rear view thereof;
FIG. 4 is a side view thereof;
FIG. 5 is another side view thereof;
FIG. 6 is a top view thereof; and,
FIG. 7 is a bottom view thereof.
The broken line showing of a mounted USB charger is for the purpose of illustrating unclaimed portions of the article and forms no part of the claimed design.