Components in an Off Grid Photovoltaics System
To collect solar energy to power your home's appliances and electronics requires numerous pieces of equipment to ensure that the system is safe, efficient, and delivers the correct type of energy to power your household items. These items include:
1. Photovoltaic Panels
Photovoltaic panels collect the solar energy, and converts it to electrical energy. The solar panels are the most visible aspect, and perhaps the most important element in the entire system and usually account for 60% of the total cost of the system. At this point, the energy produced is Direct Current (DC).
2. Array DC Disconnect
The Disconnect is used to interrupt the flow of electricity from the PV array so maintenance or troubleshooting is needed.
3. Charge Controller
A charge controller regulates the voltage and current that comes to the battery from the solar panel and prevents damage to the batteries. For smaller systems, where each panel produces less than 5 watts, you likely don't need a charge controller, but for anything larger, a charge controller will prevent damage to your batteries, extend the life of the batteries, and make your system more efficient.
4. Battery Bank
Batteries store the energy produced from the solar panels. Lead-acid deep cycle batteries are generally used for photovoltaic systems, and there are several types of these batteries available. Two of the most common batteries are flooded lead-acid batteries, which are economical and have long lives, but require regular maintenance. Sealed batteries do not require maintenance, don't emit corrosive fumes that can be produced from flooded batteries.
5. System Meter
The system meter measures your system's status and overall performance. It can tell you how full your batteries are, how much energy is being produces from the solar panels, and how much energy is being consumed. System meters aren't a necessity, but are highly recommended so you know how much energy you have and how efficiently your system is running.
6. Main DC Disconnect
The Main DC disconnect sits between the batteries and inverter, which disrupts the energy flowing to the inverter for servicing. The disconnect also protects the inverter-to-battery wiring from electrical fire.
7. Inverter
Your appliances and electronics utilize AC power, while the photovoltaic panels produce DC power. The inverter takes the DC power from the panels, and converts it to 240 Volt AC power, which is much more useful.
8. AC Breaker Panel
The Breaker is the connection between the power flowing from the electric company, or from your photovoltaic panels. From the AC breaker panel, circuits route power to various areas of your house, to be made available to appliances and electronics.
Other Items
There are of course other pieces of equipment needed, such as mounting systems and cabling, as well as enhancements to make the system more efficient, such as tracking systems, meters.