Low Voltage DC Power
This is probably the simplist set up as it is self contained. The solar panel can be directly connected to your appliance (eg a pond pump/fountain) and provide 12v or 24v DC – the same type of voltage provided by a battery. Obvoiusly the appliance will only work during daylight hours so if you want to use the energy at other times, for example lighting in your shed or garden, you will need to store it until required. This is quite simply acheived by connecting a charge controller and battery between the solar panel and appliance. The charge controller ensures that the battery does not get over charged causing irreversable damage. Any type of lead acid battery can be used, but the best batteries to use are ‘deep cycle batteries’, often called leisure batteries. Unlike car batteries, these are designed to withstand deep discharge without damage. They are made with much thicker and heavier lead plates, which are more resistant to damage, and last many times longer than conventional lead acid batteries.
An Off-grid system is an enhancement on DC system above however you can use the electricity to power all your household appliances like fridges, freezers, TV etc. You will obviously need more panels and batteries to take into account the additional power requirements. The other thing you need to do is to convert the DC output from the batteries to AC and this is done using an inverter. This output is then fed into your consumer unit for consumption around your property. For off-grid systems there is no connection to the power network so you will need to consider a backup generator to charge the batteries in the event that there is not enough solar to fully charge the batteries. Batteries can be expensive however the introduction of Lithium-Ion cells has improved the situation no end but may need to be replaced at least once or twice withn the lifetime of the PV panels. See the Battery Backup page for more details
In addition the off-grid system is elegible for the Clean Energy Cashback scheme (also known as a Feed-in tariff or FIT) where you are paid for every kWh of electricity you generate, whether you use it or sell back to the grid. See the FIT & RHI page for more details.