Today, I noticed that my car’s battery voltage was at 9 volts, which seems unusually low. For some context, I recently made a couple of changes: I switched the CANBUS to the 7N0 variant and coded it properly I also have an rcd330 as well as the adapter for MSFW (Multifunction Steering Wheel) functionality with my RCD330. But I’m still getting battery drain, could this just be a faulty battery if not what else can I do to check?