Sounds like your converter is not putting out. The small battery charger is not keeping up with usage.
You need to check to see if there is a tripped 120 volt AC circuit breaker in your electrical panel that feeds the converter. Cycle all the breakers to off, applying light pressure toward off. Then turn main breaker on, followed by the branch breakers one at a time.
Have the converter output checked. It could be the reverse polarity fuses in your converter if equipped.
It would be helpful to say what make, model and type of rig you have.