No, the controller and converter have to be separate chargers on the batteries, but you can use the existing converter to battery path as long as you join in at the converter's DC OUTPUT so they are in parallel. Also never let the converter charge through the controller.
1. 1991 Oakland 28DB Class C
on Ford E350-460-7.5 Gas EFI
Photo in Profile
2. 1991 Bighorn 9.5ft Truck Camper on 2003 Chev 2500HD 6.0 Gas
See Profile for Electronic set-ups for 1. and 2.