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.

Components of a stand-alone system with an inverter. Components in this image: 1. PV source 2. Charge controller 3. Battery bank 4. Inverter 5. Power distribution 6. Mounting system 7. Wire 8. Overcurrent protection/disconnects 9. Grounding system 10. Physical wire protection

PV source

A PV system has a PV source - one or more PV modules - that converts 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 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

A charge controller or inverter-charger is essential as batteries have specific charging requirements and proper charging is essential to ensuring that they have a long life. A system may have multple parallel charging sources.

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.

Power distribution

A stand-alone PV system requires some type of power distribution with busbars to be able to distrbute electricity safely to 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 are connected together with wire that must be appropriate for the voltage, current and conditions to which it will be subjected.

Overcurrent protection/disconnects

All equipment in a PV system - wires and all components - have a maximum amount of current that they can handle and should therefore be protected from currents that could exceed their maximum rated current. Otherwise, an electrical fire can result. Devices that protect equipment from excess current are called overcurrent protection devices (OCPDs), the most common of which are breakers and fuses. Additionally, in any system it is necessary to isolate all components of a PV system from all potential power sources in order to be able to work safely for maintenance or troubleshooting. Both of these functions can be often be performed by an overcurrent protection device, but a seperate means of disconnection may be necessary for various components. For all articles on OCPDs and disconnects see overcurrent protection and disconnects.

Grounding system

A properly built grounding system ensures safety for users and protections the system equipment against damage from lightning. Small PV systems often do not incorporate a grounding system due to cost, but the benefit of proper grounding increases as system size and cost increases.

Physical wire protection

If a wire could potentially be damaged by the conditions in which it is installed, weather, rodents, building occupants or any other source , it is necessary to provide physical wire protection