Answer Posted / sandeep mulik

wattage X 20% then divde by lowest volage of battery say 12v
is 10.4 or 10.5 then multiply by no of batteries i.e ( dc bus )

e.g 700 watt x 20% = 840 watts.

then lowest battery voltage is 10.5 assume dc bus is 36 v
means 3 nos battery then , 10.5 X 3 = 31.5

now , 840 / 31.5 = 26.66 amp per hour so use 26 amp battery
X 3nos for 1 kva online ups will give 1 hour backup.

if you want for 2 hrs then , 26.66 X 2 = 53.33 ah , you will
require 60 ah battery for backup of 2hrs .

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