What Is A Solar Inverter And What Does It Do?

You don't have to read far on any pages about solar energy systems before you come across the reference to a solar inverter.

A solar inverter is a crucial part of any solar electricity system that is grid-tied – that is designed to be connected to your local utility company.

Its function is relatively simple – it converts the direct current generated by your solar panels into an alternating current suitable for your local electricity supply.

There are two main types of inverters:

Stand-Alone Or Off-Grid Inverters

These solar inverters are, as the name states, not connected to your electricity grid.

To use them in your system you need a battery bank which stores the direct current from your solar panel. The inverter draws the direct current from the battery and converts it into alternating current to power your appliances.

They are commonly used in remote locations, when camping, and are connected to your car/truck battery.

With all inverters it is important that everything matches. That is, the input voltage from the batteries must match up with the inverter. If you have a single 12 volt battery then the inverter must be rated accordingly. If you are using a battery bank with 48 volts then the inverter must match that. Similarly, the output voltage must match up with your household electricity voltage, normally 120 or 240 volts.

Grid-Tied Inverters

In this case the inverters are linked to the electricity grid and provide an excellent solution and save on an expensive battery bank. However they are a lot more expensive than off-grid types.

One downside is that if there is a power outage then you have a power outage as there is no battery back-up.

Other Important Issues With Solar Inverters

  • You need to determine your overall power needs in choosing your inverter as they are rated in watts as to output. If you want to power your whole house from your solar panel system then you may need, say, a 5000 watt inverter.

    On the other hand, if you wanted just to run a few appliances, you could use a 1000 watt inverter.

    Unless you are pretty familiar with the appliance usage in your home, you may wish to consult your local electrician as to the correct size inverter for your needs.

  • Inverters also have some other variations. They are classified as pure sine-wave inverters or modified sine-wave inverters. The pure-sine wave inverters are those that match up with your household electricity and their output is often referred to as “clean” electricity. The modified sine-wave inverters produce what is known as “dirty” electricity which is fine for many things that don't have sensitive electronics. However, items such as PCs, TVs and LED lights may well malfunction with a modified sine-wave inverter. Some people use them, though, with few problems – they are certainly much cheaper.
  • There is an important standards issue with inverters that you need to be aware of. If there is a power outage and your inverter is still feeding into the grid it creates a life-threatening situation for any repair person. Therefore inverters are programmed so as cease output in the event of an outage. It is worth checking with your dealer that any inverter you are buying meets this standard. If you stick with recognized brands you will be fine.

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