Are these all linked to ignition? i.e. ignition on = 12v on, off:off ?
a quick google seems to bring up differing SOP on different Audi models. Once ignition is off some have a 10 minute delay, some a low battery voltage threshold, some immediately off, some permanently on.
Reason I ask, is, I'm toying with getting one or two of those blackvue camera jobbies.