Battery goes flat after couple of days

sounds like there is something draining your bat, as, its dificult to say what as it could be anything, thats doing it, you need to get a multi meter leave the bat in, and check all elecy wires for any surge can take along time, to sus out the fault, when you check out the electrics make sure all is switched of switch them on and see if you are getting the say reading, not a job for someone thats not sure what to look for