This topic should be in Video game forum but I am going to help you out anyway. It should be approx three hours to recharge it fully. But look at the red light or whatever color light you have.. once the light is gone, it means that it is ready.
Actually, so far I know... Lithium-Ion battery rarely burst if anyone leave it too long but basically, it is always best for everyone to use their common sense to not leave it too long.
Merry Christmas to you too!
