Well I replaced the battery on my X-Adv last week. I mentioned above it was showing 12.4 V after lying up for a few days. I also mentioned that the starter motor seemed laboured on start up. However the bike always started on the second compression, in short after a second or so. The lower voltage and the apparent laboured starting spooked me though. Temperatures around here currently are between 5C and 9C.
So, I purchased a new battery. I fully charged it on the battery tender and installed it. After a day or two lying up the tracker on the bike again showed 12.4V for the NEW battery. Wtf is going on I think. This morning after the bike was lying up for a week the tracker was showing 12.3V on the new battery after a very cold night. I fired up the bike and again after an apparent laboured two compressions again it fired up after a second. While the motor is running, the tracker shows the voltage to be 14.3V. Immediately after two start ups with the bike running from cold for a couple of minutes I switched off and the tracker shows 12.7 and 12.9V respectively.
I then rang my Tech, thinking that there might be a diode problem with the alternator. However He assured me that there isn't because there would be a drastically bigger drop in voltage after a couple of days if there was a diode issue. I mentioned the apparent labouring of the starter motor and again he dismissed this as a feature of the type of starter motor in the bike. he quoted me a friends Ducati 1250 Enduro where on startup one would think that the battery was about to die completely, but it always fires up.
He accepts that there is a draw by the bikes own electronics and the tracker, but the draw is miniscule. He is also suggesting that the colder weather is a factor in the slightly low reading of the battery. In short he assesses that there is/was nothing wrong with either battery and that I probably jumped the gun by purchasing a new one.
So, it looks like I now have two good batteries for my X-Adv.