Your charger , coach battery, and chassis battery all go to your BCC box under the hood.
The converter says it should put out 13.6 and has reverse protection. You may have it hooked up backwards. One output goes to the chassis battery and one output goes to your gen.
If you have reset the curcuit breakers go to the chassis battery and follow the ground wire it bolts to the chassis , mine came loose and caused strange problems. If you look up battery control center you will find troubleshooting and diagrams