Your converter must have failed as it should automatically increase/decrease charge rates depending on the state of charge.
If it's under warranty return it. If it's new to you check with converter manufacturer as how to check the setting, as the previous owner may have changed it.
Or the battery just failed, they're only good for about 5 years.
You didn't state the year, model, brand or whether it's new or used, all of which would be helpful when asking questions.
Danny & Linda
Sold our '13 Thor Redwood 36 FB
Currently RV & truckless