As a battery charges (accepts and stores amp-hours), the voltage and current rate must constantly be evaluated and modified to ensure that any given battery will not be overcharged or undercharged, yet charged fully. A sophisticated, processor-controlled, three-step charger is needed to accomplish this. I’m a fan of employing the stock converter as a converter only, but to add an aftermarket, multi-step battery charger to be solely in charge of keeping the battery bank(s) fully charged while connected to shore power. The newer technology allows for an RV to be kept plugged in all the time, without the risk of overcharging or “cooking” the batteries in the system. Some are applicable to the various types of RV batteries; wet cell, AGM, gel, etc. I would suggest you upgrade at some point. Until then, if you opt to leave the coach plugged in all the time, be sure to inspect the condition of the batteries every couple of days. Unplug the coach or disable the converter, (simply turn the circuit breaker off), if overcharging or gassing at the batteries is discovered.
Some RVers have used a timer placed in the AC circuit of the converter to only allow it to operate at certain times. But I’d rather see the stock converter convert and a separate battery charger charge.