UPS Backup Time Dropped

Only battery bank output voltage does not gives you correct information, check output current of each battery string by using a clamp-on meter, and check voltage at individual battery terminals.

To be sure if there is a problem, carry out battery dischrge test.

Selection for hot standby (Dual redundant) from the current parallel redundant operation should be ascertained from equipment manual if so required for the discharge testing so that you do not need to disrupt normal operation.

I am aware that sometimes when the vendor's technicians are called for periodic maintainance etc, as they have password they may alter the relay datum parameters by mistake.

Thanks sir,

is there any other reasion to why am facing this problem sir?

Thanks for your good answers and rapid responce.