This is completely normal behavior for a Ball Python. Some of mine come out at night while others don't come out except for when feeding day comes around. A popular quote around here is: "a hiding Ball Python is a happy Ball Python". There might be another reason he's hiding which is shedding. If a BP is going into shed, you'll usually won't see him till after he sheds which might take about a week give or take. So, don't worry. I'm sure your BP is happy in his new home.