Here's my understanding, I'm sure other will pipe in and correct
Battery chargers ... older ones, will not stop charging when the bat had reach 100% charged, many will continue to trickle charge and you run the risk of overcharging and boiling the eletrolyte (water) and killing your bat SOON!
Univolts or Intellichargers (debate forthcomming Im sure)
electronically sense the battery state and the charge rate and adjust or turn off flow accordingly. As well as providing 110v AC
DC conversion to the camper.
I purchased a "modern" bat charger that has this similar feature.
and use it when my little solar hook up doesn't gen the amps.
This was before I "found" the old sears bat charger under the curbside goucho.
Not sure if in the long run I will move towards a "real" univolt.
I am leary of digging into the "Rue Goldberg" solution on hand.
The previous "electrical engineer savant" owner added a panel with volt meters, amp meters and several DPDT switches that I am still figuring out. Even more curious is that the switches and gauges are under the goucho. Completely out of view and unreachable without removing the bottom cushion.