I would start by looking at any after marked goodies that have been connected to the battery!! It's rare that any manufacturer has electrical issues as most of the circuits are powered off by the ignition key. If you have no aftermarket gadgets connected to the battery then start by checking anything that is plugged into the cigarette lighter plugs in the car (remember these are NOT switched off, they are hot all the time), so anything plugged into a cigarette lighter plug will flatten your battery. after that you are going to have to connect an in-line current meter to the battery terminal to see the current draw and then start pulling fuses until you see the current drop, that will then tell you what circuit is drawing the current. then investigate that circuit further to find the cause. Its a long slow process.. Hopefully you have left some gadget plugged into a cigarette lighter plug and that is causing your issues!! Radar detector, USB battery charger, etc.
Gary
