Going to try to explain this....LOL...Need help

With shore power on so converter working, you should show all four lights on plus out at the battery you should be getting at least 13.6v across the battery posts. If all you get at the battery is 12.x, then you have an open on the converter-battery path.

That is usually the battery disconnect switch you operate, or else the battery fuse on the pos wire near the battery. That "fuse" might be a DC circuit breaker instead. If so, some of those can be reset by pushing a little black button.