My last battery was a sealed unit. It was a Diehard, and probably about 8-10 years old. I have no idea what Pat Price means by fussy in charging, or by not waving goodbye because none of that happened. It installed normally, it acted normally, and charged normally over its life. While my car was having some work done on it in the past two years, and just before it was returned to me, my service facility tested it and said that one cell is almost dead and another cell is marginal, so it tested like a normal battery as well. So, while it was working, it was not working well nor up to capacity. My guy wasn't trying to make a fast buck on my with a battery (trust me a mere pittance of the overall charges for restoring the hard top, replacing the door, etc.) but he was concerned that with the car being transported to me, if they had to jump it to get it out of the truck, anything can happen with that and the hood open...so we replaced it with another sealed unit.
The two unsealed batteries that I had over the years were the fussy ones in which you needed to maintain them by adding water on a regular basis, cell by cell. But that quaint maintenance was not the issue…the issue was when you weren’t looking and when you didn’t know it somehow some of the battery acid would bubble out of the tops which are not sealed, and dribble down into the battery tray and related, and that caused corrosion, some of it seen and some of it not seen unless you removed the battery. There was also a build up of that corrosive white fluff at the terminal posts, but they do make those little felt thingies that are chemically treated to help prevent that.
I cannot say that the AGM battery I last had lasted any longer or was any “better in performance” than the prior one but it certainly was a lot cleaner. It lasted probably close to 10 years which is about all you can expect out of a battery no matter what, so I’m not complaining.
