Given potential delivery of adequate ampere hours (converter rating versus bank AH rating at 20 hrs) there is no excuse for any converter to not charge unsulfated batteries within a 240 minute period of operation to 100% capacity. Four hours. Either a "converter" cuts-the-mustard or it doesn't.
Converters for Power Pole Princess roles, need only maintain correct float voltage values despite the load on the batteries (constant battery voltage does not need more than one stage). Simply put this means correct float voltage maintained despite load.
Discharge battery to 50%
Eliminate all hotel burden
Can your converter recharge your battery to 100.00000% in four hours or less?
This is absolutely aside from the question of having too small a converter. Hotel burdens will skew the results so I made this question easier...
Whatever gizmo is used, if t cannot meet the above spec the amperage capacity is too small or it is not a true boondocking rated converter.