A flashing beacon is mounted on a navigation buoy in the shipping channel at a port at 30° N latitude. The load consists of a single lamp operating 1.0 s on and 3.6 s off during the hours of darkness. Hours of darkness vary from 9.8 h in July to 13.0 h in December. The lamp draws 2 A at 12 V when lighted. A flasher controls the lamp and draws 0.22 A when the lamp is on. There is a surge current of 0.39 A each time the flasher turns on. This current flows approximately 1/10th of the time the flasher is on. The design has 14 days of battery capacity. Provision has to be made to disconnect the load if the battery voltage drops below 11 V.
The available module has a rated voltage of 17.2 V at 25°C (15 V at 55°C) and 2.3 A at 1 kW/m2. The available battery has a rated capacity of 105 Ah at 12 V. Assume that maximum depth of discharge is 0%. Design the PV system.