Not a simple answer. You'd need to know how your array is installed. It most likely has either higher voltage strings to one main inverter, or else it has microinverters at each panel that produce AC to transmit down to the connection with the AC grid. Neither of those is designed to charge 12V lead acid. If your solar system will island, or run when the there is no grid power available, then it will be easiest to plug the RV in and use the existing charger. Most commercial grid tied systems won't island that I'm aware of.
If you have higher voltage DC series strings of panels, then you could find a MMPT charge controller that would charge directly from that DC output. Legality and codes would be over my pay grade. If you have micro inverters on each panel, then you'd have to re wire an output to each panel you wanted to use, and could use either a PWM or MMPT charge controller. In a SHTF scenario, you could hack the panels and hook directly to the battery bank, then remove connections when charged or at night.
