The Start/Stop function on my recently acquired (02/2018) 2015.5 V60 always shows up as "Unavailable" -OK with me since I would not use it but I'm curious. I've read about (but have not looked for) a second auxiliary battery associated with this function. I find no mention of it in the manual and a battery shop could find no reference. Are the specs anywhere and does it have any purpose beyond the Start/Stop?

A second note: Just returned from my first road trip, 1300 miles. It was mostly high speed expressway driving but included about 90 minutes of inching through New York traffic (and the expressway speeds were well above the fuel sparing range) I used 40 gallons of fuel - not the EPA "Highway" figure but it was very convenient to need only 2 fuel stops, starting with a full tank. The "miles until empty" read out suggested a 600 mile range for pure highway driving. I found it to be an excellent road car - perhaps not quite as smooth riding as its predecessor, an '09 V70 3.2, but much more responsive and the BLS is handy on crowded roads.

 

The Start/Stop battery is located in the cold zone, under the cowl panel at the base of the windshield on the passenger side. It is only used to run the electrical system when the engine is switched off during a Start/Stop sequence.