The pos wire out by the battery will have a fuse or a DC circuit breaker there that might be too small in amps now.
You have an opportunity here to mount the new converter up front close to the battery bank, which will improve the DC charging by having shorter wires to the battery (needs a fuse on pos wire to battery near the battery) But you need a 120v receptacle up there to plug the converter into. (which you can add if needed)
Some people do that by putting it under the bed or sofa , whatever you have there on the inside of the front cap. Usually, they drill a hole in the floor for the wires to go down and then up to the tongue instead of going through the front cap.
While you are at it, you could add an inverter in the same place by the converter. The inverter fat DC wires can go over to the converter (or VV) and then just the one set of fat wires can go out to the battery bank. You then have to arrange one of several ways to get the 120v from the inverter to the items you want to be live when the inverter is on.
The existing battery to DC fuse panel wires would stay the same to carry RV loads from either the battery as now, or also now from the new converter. Those loads are all low amp stuff, not high amps stuff like charging, so those wires are fine for that as you know since they work now.
🙂Saves lots of work removing the old converter and maybe having to re-wire--not easy to "pull wire" in an RV!
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.