Inverters use DC power and convert it to 240 V AC ready for use by your household appliances.
Grid connect solar PV systems feed unused power into the electricity grid during daylight hours. During night time or when your own electricity demand is more than what your PV system is producing, the system draws electricity from the grid. All this is done automatically.
Advantages of a grid connect system are:
- No need for batteries, as electricity is not stored but either fed into, or drawn from the electricity grid
- The potential to reduce your electricity bill or even make a profit (depending on the deal you have with Ergon / your electricity supplier)
- Your lifestyle does not have to change - even a small system can help reduce your electricity bill, as your peak loads can be powered from the grid
Things to be aware of:
- Grid connect inverters must shut down in the event of a power failure (grid failure) - this is a safety feature required by your electricity supplier
- Grid connect inverters have been designed to synchronise (tune themselves) with the electricity grid frequency. If you want to use your PV system during a power failure, you will need to use an Off Grid inverter to act as the electricity grid for your Grid Connect inverter. The two of them will then power your house/farm as an Off Grid system.
Other notes of interest:
- From the photos you will notice that manufacturers often use one housing design for a number of models with different output.
- There are 2 types of inverters: those that use transformers and those that don't (using switchmode technology instead). The new trend of transformer-less inverters are much lighter, and also generally more efficient.