Welcome to iRV2.
Do you have a volt meter and a 12 volt test light ?
Two very important tools for electrical problems , about $30 at Harbor Freight for the two.
If you installed two or four batteries , the first picture below is how they should be hooked up .
There should also be a master fuse or circuit breaker for the 12 volt cables close to the batteries ( with-in two to three feet ) mine are 135 amp , because they have to handle the gen set starter draw.
Do you have separate , converter/charger and inverter , or is it an all in one unit .
Do you have the manuals for the unit?
There should be fuses or circuit breakers on the unit too.
The second picture is the main fuses , located on the frame behind the battery tray on my coach , one for chassis battery systems the other for coach systems.
Info , on this site may be of some help too.