System Design Choices

Once we have the data, we can make some choices or decisions on:

The type of photovoltaic module to use
The type of battery to use
The type of charge controller to use (not forgetting to account for its consumption)
Any other special equipment to use (e.g. inverters to provide 230Vac)
The expected losses in cables and diodes
The expected losses from build-up of dust on the modules, module cover damage due to sandstorms, etc
The tilt angle and direction to use for the photovoltaic array (taking into account any limitations due to the site)
Whether we optimise for the lowest cost combination of array size and battery or whether we always want the battery to be fully charged as often as possible

And in special cases:

The higher operating temperature of photovoltaic modules if they are mounted on a building, rather than having free air access
The type of temperature environment that the batteries will be in (this can seriously affect battery life) and whether to provide some special cooling (and/or heating) at some times of the year.

Predicting the energy of a system of pre-defined size.