Components that Make PV System

PV Modules: are the source of power in a PV system. They produce DC electricity.

PV Racking hold the PV array to the location where you want to place your PV modules.

PV modules and PV panel are used interchangeably. But if you want to be precise then:

A module is a single unit consisting of PV cells.
A panel is a group of modules fastened and wired together.
An array is consists of all the modules and racking components that give you DC electricity. 

Battery Bank: is used for energy storage. Multiple batteries can be connected together to achieve specific voltage and desired energy capacities. Two most common types of batteries are:

1. Sealed Batteries: These batteries are sealed and require minimum maintenance by the end user. These batteries are often presented as maintenance free batteries but actually they are not. Although they are sealed, still they need your attention.
2. Flooded Batteries: These batteries have flooded container and require maximum maintenance by the end user.

An important precaution that need to be handle for batteries as all batteries (maintenance free too) release gases.  Batteries should be kept inside a protective container that vents to the outside to avoid the possibility of gasses buildup and an explosion.

In PV system a Battery Monitor should be connected to batteries to keep track of their charging levels.

Charge controllers: The primary function of charge controller is to control the charge coming out from the PV array. Charge controllers have different features, technology and sizing options. 

Inverters: Inverters are used to convert DC power produced by PV array or stored by the battery bank into the AC power used in homes and businesses. An inverter can be as small as the 100W unit to as big as few megawatt unit.

For PV system two types of inverters are used:

• Utility-Interactive
• Stand-Alone

Loads: Loads are all the pieces of electrical equipment that you use in your home or in your offices. You can have either DC load or AC load. In some cases you have both loads. For users who have both loads their PV system should contain load center that intelligently handle this situation.

Protection: Protective equipment should also be used to avoid electrocution. Your PV system should provide the features like overcurrent protection, overvoltage protection, undervoltage protection, thermal protection etc.