Inverters
Inverters come in various forms and shapes, from 12 to 48 volt and from 300W to 10 kW. Price and quality vary hugely and pure sin/modified sin inverters are not the same
Inverters are basically voltage converters. They normally work of 12,24 or 48 volts and are powered by batteries. The typical range is 300 to 2000 watts, however you will find plenty which are bigger and smaller then this.
Simplified, Inverters work by taking the direct current (DC), converting it to alternating current (AC). This is done by switching the current direction 100 times a second, giving a frequency of 50HZ (2 switches is 1 HZ). This switching takes place in a vacuum tube.
Once you have AC current you can change the voltage using a transformer with different windings on a toroid. The difference in windings is what will either boost or decrease the voltage. The amps are opposite proportional to this, however current can be limited with resistors and other electronic devised.
Once the voltage has reached 240 volts, it is ready to be used by most electrical appliances. The greater the amount of watts the inverter is capable of producing, the stronger the components must be to handle and the more heat mush be dissipated (energy is lost just as a battery charger gets warm)
There are two types of inverters. Pure sin inverters output is basically like a wave on the sea. It has a curve and is rounded. The Modified sin wave on the other hand is totally square. It is either on or off, giving it the appearance of a series of box like squares on an oscillometer.
Because of the softer wave form of the Pure sin it has wide application and some electrical items such as flourescent light will only work with Pure sin.
The reason inverters are not run directly of the solar panel is because electrical appliances have a surge of power when powered up, therefore you do need to use a battery with your Inverter.
There are a number of inverters and a number of technologies, many of which are very advanced. Efficiency varies from 85% to 99% and in general, the higher the voltage, the better the efficiency. Be aware that some inverters are not approved for EU markets, do not have adequate certifications and do not last long due to poor manufacturing and use of sub standard components. It is also important to consider the safety of the inverter as it works with 240 volts which can easily be lethal, even in low power systems
For more information on Inverters see
