Mark,
Sounds like your alternator may have failed. The first place to check is the back of the alternator with a volt meter with engine running. If working properly it should read 14 or so volts. If this checks ok, then on to the batteries. Check voltage there. Again, 14 or so volts. If all this is good, then inverter would be next. It’s also possible that the battery isolator is not working properly. It is between the alternator and chassis/house batteries. There are three terminals, middle one is feed from alternator, outside ones to chassis and or house batteries. If alternator has failed, you can run generator to charge batteries until you can fix alternator. Hope this helps.