I have the Triplite 1250 inverter charger, it has auto switching from 12v to 110v, when the shore line is not there, and it has 110v pass thru. This allows me to always have 110v at the outlets.
It is a modified sine wave, not pure, so things like a fan runs, but sounds differently, like it choppy. ( I didn't realize that when I bought it, or I might have gone a different way.)
But, it does act like a UPS, and a line conditioner if you will. So, when constant power is required, it's there.
The other down side is that I don't really know what the 3 stages of the charging cycles are.
The manual does not specifically say the actual numbers. There is a choice for AGM's or flooded via a switch.
TMI, or is that what you needed?