Inverter Issue

Our inverter is not working right and I'm not expert on them. The system shows and charges ok that the battery is almost full. When we put anything on such as coffee maker, tv or whatever, it goes into an error mode and shows low battery start charge. When that happens nothing works not even the generator which really puzzles me. We left the campground and stopped at a rest area and first try the genset started. Next dry camp, same problem. No LED lite is lit on the inverter either. I have shut it down and restarted and all looks good until we try to put any load on it. This all started when we had the tv on for no more than an hour and everything went out and the error light came on and no genset start.

Any thoughts, is our inverter shot???

Thanks,
Bob