The ornamental design for a batteryholder, as shown and described.
FIG. 1 is a front view of the battery holder of the present invention;
FIG. 2 is a top view of the battery holder of FIG. 1;
FIG. 3 is a back view of the battery holder of FIG. 2;
FIG. 4 is a bottom view of the battery holder of FIG. 2;
FIG. 5 is a right side view of the battery holder of FIG. 2; and,
FIG. 6 is a left side view of the battery holder of FIG. 2.
The broken lines delineating 12 small rectangles in FIGS. 2 and 4 are for the purpose of illustrating unclaimed portions of the battery holder and form no part of the claimed design.