I have a 2005 12GS and a 2006 HP2. Both are hard on batteries. It is not a software upgrade issue or an accessory issue. With the ignition switched off I carefully measured the current drain on the battery by putting an amp meter in series with the battery cables. Both bikes showed an off current drain of about 5 milliamps. The stock battery will lose enough capacity with this current drain to not be able to start the bike after about three weeks time (at normal temperature - less than three weeks at low temperatures). It is an unavoidable fact of life that you need a battery tender if these bikes are not used regularly (every week or so).
my favorite bike - R1200GS