Basic stand-alone PV system components
Stand-alone PV systems, regardless of where one is at in the world, share the same basic components. This article will give a high level overview with links to more detailed information on each component.
Contents
PV source
A PV system has one or more modules that convert the energy of the sun into electrical current. Solar PV modules use the photovoltaic (PV) effect to generate electrical current upon exposure to light. If there are multiple modules in the system, they are typically arranged into what is referred to as an array. The term array may be used for simplicity even if there is only one module in the system.
Energy storage
A stand-alone PV system requires some type of energy storage system - typically batteries - in order to provide energy at night or during periods of bad weather. If there are multiple batteries in a system they are arranged together into what is referred to as a battery bank. The term battery bank may be used for simplicity even if there is only one battery in the system.
Charge controller
Batteries have specific charging requirements and proper charging to essentially to ensuring that they have a long life. In all systems with batteries it is necessary to have a charge controller or an inverter-charger that is capable of properly regulation the charging of the battery bank. A system may have multple parallel charging sources as well.
Inverter
In order to power alternating current loads, it is necessary to have an inverter in a stand-alone system. The battery bank provides a stable voltage and current to the inverter, which it can then convert into stable alternating current to supply AC loads.
Mounting system
PV modules must be anchored to some type of mounting system to ensure that their production is maximized with the correct orientation and angle relative to the sun, but also to ensure that they are not damaged by weather.
Wire
All of the different electrical components of a system need to be connected together with wire that is appropriate for the voltage, current and conditions to which it will be subjected.
Overcurrent protection
All wires have a maximum rated current that they can handle. If this number is exceeded, an electrical fire can result. If a wire could potentially be supplied with more current than it can handle, then it is necessary to protect it with an overcurrent protection device such as a breaker or fuse.
Physical wire protection
Wires have specific conditions in which they can be installed. If a wire could potentially be damaged by weather, rodents, building occupants or any other source , it is necessary to protect the wire with some type of conduit.
