Lead Acid  = 1500 cycles at 50% DOD = 750 full cycles possible at 50% DOD ( MAX ) 

Karachi 280 Ah 12V tubular = Rs 47,000

50% DOD = 280 Ah x 12v x 0.5 = 1680 watt hours = 1.68 KWH

1500 cycles = 2520 kwh over life

Rs 47,000 / 2520 kwh = Rs 18.65 per kwh. 

Capital cost per kwh = 47,000 / 1.68 kwh = Rs 27,976 per kwh