Problems related to inverter

The inverter’s voltage drops from 240V to 110V while it is connected to the load, so what could be the problem

It’s a problem with the oscillator circuit. There’s no feedback to the oscillator making it an open-loop system. Feedback keeps the voltage constant irrespective of the load. It’s not the battery issue. If the battery is low, the voltage comparator circuit senses that without a voltage drop at the output, sends a signal to the user and later shut down the system by cutting power from the oscillator circuit but system output voltage remains constant all. Through. That’s what I feel is happening.