I turned the car off and measured the voltage across the battery again and it's reading 12.4 V. That doesn't make sense to me because there's no way the battery charged up in the short five minutes I had the car on. That seems normal because right after driving the battery has some extra voltage th...

I have had ongoing issues with battery drain on my Volvo S80 for about the last two years. When I am commuting on a regular basis (~1:15 hour daily) there are no issues and everything works fine. The trouble starts when the car sits for a few days, then it becomes hard to get the car to start. After...