Charles was a mixed bag over his last four holes with two birdies, a bogey and a double bogey on the par-four sixth.
His one-over-par total has him in a tie for 68th after the morning session at The Hills.
The clubhouse leaders are Americans Josh Teater and Todd Demsey.
Teater was flourishing in perfect conditions and looked on track to post a ine-under-par 63, the equal second-best score in Open history.
But he struggled on 18, finishing with a double-bogey six, dragging him back to a seven-under 65 alongside Demsey.
New Zealand amateur Danny Lee bogied three of his last four holes to finish with a one-under 71.