My application is basically a power monitoring system in which inverter voltage(RMS),current(RMS) and battery voltage,current are measured. 24V battery is being used in the application. I am using PIC16F877A microcontroller for measuring and do the rest of the functions based on the readings. ADC code is working fine. It is measuring the battery voltage correctly if it is isolated from charging or discharging. But whenever I connect the battery to charging and inverter circuit the ADC is measuring only a constant value, in my case 25.7V even if the battery is charging. but multimeter is reading incremental voltage as battery charges. I am using a simple voltage divider to step down the voltage to a microcontroller level voltage.I have added a 100nF cap to ADC input but didn't help. Is there anything I need to consider in circuit side or firmware side to do accurate measurement.