My response is not meant as a criticism, but I would suggest that you take a minute or two to go on the B&H site, type "Nikon EN-EL18d battery" into the search function, click on "reviews" & read over the 13 one-star (as of this writing) ratings. I haven't even investigated reviews on other sites (Adorama, Amazon, etc.), but would expect to find more of the same. My WAG is that, more than likely, none of them are due to a bad charger.
IMHO, the problems with this model battery are well-documented. There are obviously many defective EN-EL18d batteries being sold. Some defective batteries are obvious right away. Others take a short time in use.