The mains power supply in domestic homes is AC power. This means that the voltage cycles back and forth at regular intervals. In Australia this power cycle is 50 times per second (50Hz), with a voltage of 240 volts RMS.
The 50 Hz voltage cycle can take one of several forms. It might very smoothly alternate between the high and low voltage, which is a sine wave. Or it might sharply jump from high to low voltage, which is a square wave. There are also a few other possible waves. In terms of supplying power these different waves are quite similar, but some electrical equipment will not tolerate sharply changing voltages like square waves. Square wave AS power can badly damage some electrical equipment, specifically computers and digital equipment.
The mains AC power from the city wide electrical grid (i.e.: the power lines that run to most homes) will be close to a smooth sine wave. This is usually quite fine for almost any electrical equipment. The power from a solar battery system depends on the inverter. Some good quality inverters supply smooth sine wave power. Other inverters supply hard square wave power, which can be used for most, but not all, electrical devices.
Electrical equipment that will not tolerate non-sine mains power.
- Printers, especially laser printers, can be damaged by non-sine wave equipment.
- Likewise, some Photostat machines (photocopiers) are damaged by non-sine wave equipment.
- Photographic strobes / photo flashes may be damaged by non-sine wave equipment.
- Audio equipment may not usually be damaged by non-sine wave power, but they will often suffer interference. The speakers may produce an audible buzz.
- Television reception may be compromised by non-sine wave power.
- Some fluorescent light may not work with non-sine wave inverters.
- Some fan and motors may run faster than usual with non-sine power supplies, though this is not usually harmful.
A modified sine-wave inverter is another option. This modifies the square wave to something that is similar to, but not quite identical with, a sine wave. These are a reasonable compromise both in terms of performance and equipment cost.
A good inverter is part of the solar panel cost. Make sure you have an inverter that supplies adequate power for the home, and which supplies clean power for sensitive (usually digital) equipment.
Talk to the solar panels specialist about the power requirements in your home. Almost every modern home has an internet connection and at least one computer. Make sure all this computer equipment has a suitably clean power supply either from the commercial solar system or from a filtered power supply.