The ornamental design for a batteryadapter, as shown and described.
FIG. 1 is a perspective view of the battery adapter.
FIG. 2 is a front view for the battery adapter shown in FIG. 1.
FIG. 3 is a rear view for the battery adapter shown in FIG. 1.
FIG. 4 is a left side view for the battery adapter shown in FIG. 1; The right side view is a mirror image of the left side view.
FIG. 5 is a top view for the battery adapter shown in FIG. 1.
FIG. 6 is a bottom view for the battery adapter shown in FIG. 1; The broken line in the drawing is for the purpose of illustrating the unclaimed portion and form no part of the claimed design; and,
FIG. 7 is an exploded view for the battery adapter shown in FIG. 1.