Battery draining overnight?

I recently replaced the alternator and before that the power steering pump along with plugs, plug wires, battery. I've gone through everything I can think of and still the battery (the one in it is the 3rd one since I started) is still going dead overnight. I charge it and it'll crank right up only to be dead the next day. I have put the digital multimeter on it and the battery reads 12.7(the battery was brand new) and reads 13.9 when I crank it up. I have checked the fuses and no blown there. I understand that it's probably something I did that somehow left a circuit open and drains the battery, but I am at my wits end as to what.