Audi Q4 e-tron battery drain overnight is usually a 12V battery issue, not the high-voltage pack. Here is how to find the parasitic draw and whether you can keep driving.
First, a quick reality check
On a Q4 e-tron, the battery that usually dies overnight is the 12V battery, not the big high-voltage pack. That small battery powers the computers, door modules, infotainment, telematics, and the electronics that wake the car. A healthy Q4 should go to sleep roughly 20 to 60 minutes after you lock it. If something keeps a module awake, it can pull 100 mA or several amps continuously and kill the 12V battery by morning. If the car still starts and drives normally, it is usually safe to drive to a workshop soon, but do not ignore it. Low voltage can cause random warnings, no-start conditions, and eventually leave you stranded.
