Inverter shifting to backup even when mains is ON

[pgcp]

Installed a new inverter today.
Exide home UPS 1450 VA
attached with 2 exide invamore T plate batteries (150AH each) (new)
Sometimes the inverter is shifting to battery backup even when the mains power is still ON.

Additional info :-

• 
  
  Input voltage in the range of 175-210 V
  
  No overload or high voltage situation
  
  After switching off the inverter power on/of switch, battery starts charging. charges for 10-15 seconds & agai the same problem occurs.
  
  Many times charging doesnt start even after flipping power on/of switch.
  
  After hours now the batteries are fully charged at 27.4 V (as shown in the display) & problem seems to have disappeared for now

What seems to be the problem?

 

[anirbandd]

Get it checked under warranty.

There are simply too many points in the circuit to guess where its faulty.

 

[saswat23]

Inverter will shift to batter only when:
1. There is a power cut
2. Mains voltage is very very low

If none of these, then get it checked.