Please clarify your terminology. You likely have a "converter", not an "inverter/charger" . There is no such thing as a "charger inverter"
You likely have a single stage (13.7ish volts) Parallax 7300 converter in the 2006 Class C, or perhaps an Iota or PD or WFCO version of the same thing.
You can't meet the AGM battery charging specs with the plain version of one of those. You will need a charger that can do 14.4 volts and you will need ammeter to measure when charging gets down to 1/2 an amp per 100AH of battery. Easiest way to do that is with a battery monitor that shows amps.
