I've got an '03 XC70 2.5 turbo.
I had an odd event this afternoon. I parked the car in about 90°F heat after driving it about 5 miles on the highway. Came back about 1hr later and it tried to start by 'pulling' the engine with much effort once. Every other attempt to start resulted in the starter 'clicking' and the dashboard power flickering. Apparently the battery had gone dead, and a jump start put us back in business.
I've never had a battery issue with the car in the year that I've owned it. I exposed the battery when I got home (after 2 more successful starts) and it is about 12.6VDC and the electrolyte levels look good. I know the lights were not switched on.
What could be going on? Is there something else I should be checking on? The only thing I could possibly imagine is if the A/C fans that run to keep down humidity somehow were causing too much drain or were somehow failing. But that's just a stab in the dark.
Any insight would be appreciated!