First find MAIN DC Dist Panel......has all the 'house' DC Individual circuit Fuses
Close by/behind it/next to it would be the converter
Question.....
Whenever I read 'new batteries' I have to ask
Did you mark battery cables prior to removal, if not did you trace battery cables prior to connecting to new battery.
If connected backwards.......'reverse polarity' fuses (30A or larger on converter) blow to protect converter electronics
If blown ---no DC from battery OR from converter when on AC