So i have a new battery and a good/tested alternator. But my battery keeps loosing all its power overnight. i go to start it and its dead?

Has anyone else had a short or a slow drain on their battery?
How much did it cost to find the short? Where did you take it?

I'm really at my wits end on this one , need a professional.
suggestions?

 

i also have a drain but i've been too lazy to do a parasitic draw test.
it's very simple to do. just get a multimeter, disconnect the negative battery terminal and start pulling fuses one at a time

 

what will happen when you get to the right fuse? I've never really messed with test meters before though i have a good one.