An off-grid system is not connected to the electricity grid and therefore requires battery storage. Off-grid solar systems must be designed appropriately so that they will generate enough power throughout the year and have enough battery capacity to meet the home’s requirements, even in the depths of winter when there is generally much less sunlight.
The high cost of batteries and off-grid inverters means off-grid systems are much more expensive than on-grid systems and so are usually only needed in more remote areas that are far from the electricity grid. However battery costs are reducing rapidly, so there is now a growing market for off-grid solar battery systems even in cities and towns.
How it works
A wind generator and/or solar PV panels charge a battery and the battery supplies power to the loads as needed. All loads are run at the battery voltage (usually 12 or 24 VDC) and special appliances are often needed. Charge controllers limit the charging when the batteries are full. Meters, to monitor system operation, together with fuses to protect wiring are usually included.
To be successful, efficient use of the electricity generated is essential and the system must be sized to meet worst case conditions.
See: Off-Grid Lighting Kits
Adding an inverter
Adding an inverter is a simple way to increase the systems potential proving you the ability to use a wide range of appliances that you would use in any normal house. It converts your low voltage DC into 230VAC.
To ensure reliable system operation, the inverter should be carefully matched to the loads so that it is capable of running everything that is needed. Usually a larger wind generator, PV array and battery store will be required than for a DC only system because electrical requirements will be higher.
What it can power
Here are some examples of what you could power:
Music systems
Fridges
Lighting
Tools
TVs
Satellites
Telecoms equipment
Electric fencing
Essentially you could power anything but if your regularly using large electrical appliances we recommend you look at the Medium off-grid system.
What’s in the system
As an example here is a list of components in a typical small off grid solar PV system:
