We claim the ornamental design for a accumulator charging apparatus, as shown and described.
FIG. 1 is a perspective frontal view of the accumulator charging apparatus.
FIG. 2 is a front view thereof;
FIG. 3 is a back view thereof;
FIG. 4 is a side view thereof;
FIG. 5 is a side view thereof, opposite the side shown in FIG. 4;
FIG. 6 is a top view thereof; and,
FIG. 7 is a bottom view thereof.
The broken lines showing features of the accumulator charging apparatus are for purposes of illustration, with the features shown in broken lines forming no portion of the claimed design.