Cost of storing energy and service life

(a) An installation requires 60 cells in series to produce 120 V. Depending on the application, this output is converted to different ac voltages. The cost of a 450 A–h, twelve-cell battery is $3000. In order to get the longest possible life, the batteries are float charged. Let us assume that the batteries are float charged at 2.25 V per cell. Calculate the cost of storing energy.

(b) To meet performance requirements, the sensor needs to be activated once every 10 min for a month. What is the service life for the battery?

Note: Service life¼(total desired operational time of a sensor
cycles) / (sensing duration)