**2. Assumptions for sizing PV systems**

1. Precise estimation of solar radiation data:

It is assumed that the solar radiation available at the location is 6000 W/m<sup>2</sup> per day. The system should be designed for the month of lowest radiation.

2. Sun-tracking of solar PV modules:

Solar PV modules are considered fixed. Normally when modules are tracked to follow the sun, more energy can be generated using the same set of PV modules. Power enhancement is about 30% with the help of dual axis solar tracker but extra cost is required to implement the sun-tracking mechanism.

3. Ambient temperature in which modules and batteries are working:

The ambient temperature affects the performance of the modules and batteries. The performance of the PV modules and batteries degrades as the ambient temperature increases above 25°C. Knowledge of the variation in ambient temperature over the year can be useful in estimating the real output from the PV modules and batteries.

4. Type of PV technology used in the system:

The performance of the modules of different technologies (but same wattage) varies under the same operating conditions. For instance, a thin film module made up of amorphous Si performs better in cloudy conditions and early morning conditions than the module made up of crystalline Si wafers which is chosen.

5. Type of batteries used:

