what is the formula for backup time of online ups?

Answer Posted / sudhakar g

Hi,

First you want to know how much required for your company or home anything.....suppose we can take 1200w load we required then take 1.5kva inverter
kw=kva x p.f
1200=kva x 0.8
kva=1500

number of SMF batteries=N=6
Voltage of each DC battery = V = 12 V
Ampere-hour of each battery (AH) = X1)
Suppose incase of 2hours usage T=2hours
Volt-Ampere = (N * V * X*EFFicency)/ T
1500 = (6*12*X*0.9)/2
1500 = 33X
X= 43 AH
or else
Time=(number of batteries*voltage of battery*AH)/VA
T=(6*12*43*0.9)/1500
T=1.9hrs
Nearly 100minutes

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