It should not have caused any serious damage. Most likely you will find a fuse that is blown somewhere between the batteries and/or at the 12 volt converter.
If you can locate the battery bus bar there should be a resettable fuse there. On my 5th wheel the bus bar is near the battery mounted on the frame and has numerous wires coming off the bus bar to various places with small rubber boots surrounding them. One of those has a little square box with a very small button sticking out. This is a resettable fuse that can be reset by pushing in until it clicks.
Keep us updated as to what you find as a solution.