I have a problem and would like to address it myself if I can narrow it down. I have a new battery roughly 5. I this old, my battery kept dying over the weekend and I got it tested at autozone who said the alternator was bad. So I replaced it and over the weekend of sitting the car wouldn't start at all. Went back and the error was the same for the new alternator, "voltage regulator failed". During the week the car starts up and drives fine. There are no lights on the dash, I haven't hooked up a obdII scanner to it yet, but I'm just stuck as to what is draining my battery over the weekend but fine during the week. I do have an aftermarket radio and subs but haven't yet tested if it's drawing power when the car is off. Does anyone have any thoughts on this.