The ornamental design for a batterycharger, as shown and described.
FIG. 1 is a perspective view of a battery charger according to the present invention;
FIG. 2 is a front view of the battery charger of FIG. 1;
FIG. 3 is a back view of the battery charger of FIG. 1;
FIG. 4 is a right side view of the battery charger of FIG. 1;
FIG. 5 is a left side view of the battery charger of FIG. 1;
FIG. 6 is a top view of the battery charger of FIG. 1; and,
FIG. 7 is a bottom view of the battery charger of FIG. 1.
The broken lines in the figures merely illustrate the environment for the battery charger of the present design and therefore form no part of the claimed design.