Well, I was wrong about Delco being independent. Delphi sold the ACDelco battery division to Johnson Controls, so that leaves just three very large battery manufacturers. I have not purchased a Delco (or Delco made) battery since the buyout so I can't comment on their current quality.
I was also wrong about Delco being the only battery manufacturer that makes maintenance-free batteries. Exide makes them but they are not truly maintenance-free and sealed like the Delco design (they just contain more acid and have flush caps that can be removed with a screw driver). East Penn also makes a sealed maintenance-free battery that can not be serviced, I just saw a maintenance-free 24F in East Penn's Deka brand (model #'s 424FMF, 524FMF, 624FMF, 724FMF). East Penn's design (like Exide's) differs from Delco's in that it just has a higher acid capacity above the plates. I suspect that it vents hydrogen gas like any conventional battery where Delco's design does not (under normal circumstances).
Exide used to be a big supplier to both WalMart and Sears. In a forum I was reading, some frustrated Exide shareholders were complaining about them losing some of the big battery contracts and the stock falling because of it. Now JCI has both of those contracts (except for the sears DieHard Platinum). http://www.jsonline.com/business/83454852.html
JCI also has the NAPA contract here in the US. JCI is the 800lb gorilla of the automotive battery business, no doubt about it.
I was also wrong about Delco being the only battery manufacturer that makes maintenance-free batteries. Exide makes them but they are not truly maintenance-free and sealed like the Delco design (they just contain more acid and have flush caps that can be removed with a screw driver). East Penn also makes a sealed maintenance-free battery that can not be serviced, I just saw a maintenance-free 24F in East Penn's Deka brand (model #'s 424FMF, 524FMF, 624FMF, 724FMF). East Penn's design (like Exide's) differs from Delco's in that it just has a higher acid capacity above the plates. I suspect that it vents hydrogen gas like any conventional battery where Delco's design does not (under normal circumstances).
Exide used to be a big supplier to both WalMart and Sears. In a forum I was reading, some frustrated Exide shareholders were complaining about them losing some of the big battery contracts and the stock falling because of it. Now JCI has both of those contracts (except for the sears DieHard Platinum). http://www.jsonline.com/business/83454852.html
JCI also has the NAPA contract here in the US. JCI is the 800lb gorilla of the automotive battery business, no doubt about it.