This is what my repair shop friend told me almost word for word, they key being there are 3 manufacturers. I've also run Hawker Odessey too to save weight.
"Most auto batteries are made by just three manufacturers, Delphi, Exide, and Johnson Controls Industries. Each makes batteries sold under several different brand names. Delphi makes ACDelco and some EverStart (Wal-Mart) models. Exide makes Champion, Exide, Napa, and some EverStart batteries. Johnson Controls makes Diehard (Sears), Duralast (AutoZone), Interstate, Kirkland (Costco), Motorcraft (Ford), and some EverStarts."