This disclosure relates to a battery charging system configured to selectively charge a battery pack of an electrified vehicle. More particularly, the battery charging system is configured to interrupt a buildup of carbon deposits. A corresponding method is also disclosed. In some aspects, the techniques described herein relate to interrupting a buildup of carbon deposits on a printed circuit board of a battery charging system configured to selectively charge a battery pack of an electrified vehicle, wherein the buildup of carbon deposits follows a path between an input pin of a relay on the printed circuit board and an output pin of the relay, and wherein the buildup of carbon deposits are interrupted by a slot formed in the printed circuit board.