Answer Posted / bala_vlsi

Fomula

Watt/d.c voltage )x 1 / (p.f )x (1/ Efficiency) x Required
Hrs

Example

Data
500 W = load
12 V = d.c vOLTAGE
0.9 = P.F (ASSUMED )
0.8 = mAINTAINANCE fACTOR(ASSUMED )


500 / 12 X (1 / 0.9 ) X (1 / 0.8 )X 2= 115 AH Battery is
need to priovide 2 Hrs back up supply

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