Are you sure it is the battery and not the alternator? Normally if a battery is shot, it will give you a headache for quite a while, and it usually gives you the hardest time after the car sits over night. I feel like after you drove 30 miles, especially with a warm engine bay, it should have started. It seems that the alternator failed to charge your battery back up. So when you put the other battery in, of course it had enough CCA to turn the engine over and you were probably running off just the battery again.
2011 Ford Fusion SEL 3.0L DOHC V6
2005 Mercury Sable LS 3.0L DOHC V6 (The Beater)
2005 Ford Taurus SE 3.0L FFV OHV V6 (Sold)
2006 Ford Taurus SE 3.0L OHV V6 (Sold)
2005 Ford Taurus SEL 3.0L FFV OHV V6 (Sold)
2007 Ford Taurus SE 3.0L OHV V6 (Sold)
1999 Ford Taurus SE 3.0L OHV V6 (Sold)