As already pointed out, there are many things that are always on. In addition to the clock, the radio presets, etc., the computer is always on. The dealer should have a reference as to what the current draw is with everything off that can be off. I would suspect that value is pretty low and that anything over that is not good. They should be able to pull fuses while reading the current draw to see where the juice is going and shouldn't. Time-consuming, but not complicated.