Mine makes a random tone noise through the door speakers indicating the
Battery Management module is about to shed electrical loads to preserve the
battery. I guess yours wasn't doing this. Its a good indication that the
battery has got to around quarter charged level. At that point I hook up the charger. (Most of my trips are 15 minutes long, twice a day.) See here about
what happens in the Controller 09 diagnostics. (Bottom of the post -
Diagnostics Check with VCDS)
In the winter period where it seems to be worse due to the lower temperature and and what
charge the starter takes out of the
battery, I hook up the charger about once a month unless there's been a long trip over 1 hour of continuous driving without stop/starting the engine. In which case I just do a quick voltage check across the
battery terminals to check the
"nominal charge level".
The other point in winter, especially down at -10'C to -20'C, the
charge level needs to be kept up towards the top level as the
battery may freeze in the more discharged state.
The lights being on does not really matter. The alternator is powerful enough to cope with that and
charge the
battery. It is the low maintenance
battery that is the restriction and how much
charge it accepts while the Scirocco is being driven. A short 10 minute drive will do hardly anything to put
charge back into the
battery that the starter has removed. So over a prolong period of time (couple of months) the
battery gradually reduces "its nominal
charge level" to the point its discharged enough not to start the Scirocco.
C.