[NH_Bulldog]

Simply, the primary purpose of a battery charger is to charge a battery. The primary purpose of a converter is to convert 120v AC power to 12v DC to operate the 12v DC needs of the coach, while secondarily providing a slow charge to maintain the coach battery or batteries.

In the context of the original post, using a generator to produce shore power to your converter to then in turn provide power to slowly charge your battery or batteries is far less efficient (and more annoying to your neighbors due to the required long running time of the generator) than simply running a generator to power a battery charger which can charge your battery or batteries quicker and more efficiently.

Think of it like comparing a hatchet and a chainsaw. They will both cut a tree down, but one does it quicker and more efficiently than the other.