There are two main types of WET Lead vehicle batteries in my area, the ones you can unscrew caps on the top to top up the water/electrolyte. And the ones that are sealed on top/maintenance free & can’t be topped up, as the top plastic part is glued on & underneath are exposed openings without any caps. Most batteries now are of the sealed non topping up type.
I read in the sealed type they have a recombinant agent to turn the gasses from charging back into water.
So do these wet sealed at the top batteries last as long as the WET top-up type? Both would be well looked after & charged up frequently by DC-DC charger. Deep cycle or crank.
There are many, many sites that provide information and recommendations on batteries, especially those used for secondary power (or primary power) for an entire house.
I think that most of them would agree that wet (removable tops) batteries will last longer than sealed. Some sites say the difference is as much as 40%.
As an aside, my father’s family used glass-cased wet cells on their farm in the early 30s. (This was before the REA.) It was a regular chore to top them up and to add electrolyte each week. They lasted for many years.
What is the application? You’re a little cryptic. Stationary batteries can last a long time, in theory. Heat, and vibration, is what tends to kill them.
The quality of the materials plays a role. Purity of the sponge lead. Modern maintenance free are not all the same, AGM is what you’re describing.
Dual battery setup under bonnet of 4wd & just using deep cycle outside on its own to run camping fridges.
I’m not describing AGM. They are completed sealed. I have two.
But the Wet sealed have a plastic piece glued on top & you can’t access the holes to top up water easy at all. Under the top piece is exposed openings with liquid covering plates.
More & more wet batteries are going sealed like this as they probably are more appealing. But not to me if they last alot less.