SOLAR INVERTERS

Single Phase | 3 Phase | String Inverter | Hybrid Inverter | Battery Inverter

What are Solar Inverters and how do they work? Do you have a Single phase or 3-phase power connection? What the difference between them and how it will affect your solar system cost? Do you need a Hybrid Inverter or String Inverter just will do the job, and what are Battery Inverter for?

HOW SOLAR INVERTERS WORK?

There are many websites that go to great depth to explain "how solar inverters work”. We will just cover the fundamentals so gaining a basic understanding. Nobody really cares so long as the thing works…Of course!
The electrical power made by your solar PV is therefore fed into the inverter, which “inverts” the power. Meaning: "flips it”, and so a low voltage goes to a much higher, 240 volts. While it’s doing that, the inverter "conditions" that power therefore making it nice and smooth. Again so like what you get from the power plug. Otherwise, damage to your appliance will result. This power output is ready for use by you locally or hence, exported to the Grid. In this case, a nice feed-in tariff is welcome! Its worth to note at this stage that the "inverter" referred to could be in fact a Hybrid Inverter. It could also be a Battery Inverter too, as at this point of the process, they do the same function.

Yes, so there are a few types of inverters. Some types are therefore for “off-Grid” use. A home connected to the power Grid hence does not use this type of inverter. This set up in fact, runs solely on batteries. Then there are the more common type that we call “Grid-tied”. This is what people get when they want solar power system installed on their suburban home, and so power Grid connected. These two types of inverters are in essence, very different in the way they function. Our interest is in the “Grid-Tie” type and so specifically, single or three phases.


SINGLE OR THREE PHASE POWER CONNECTION?

Some homes have a 3-Phase power connection to the Grid, but most have 1-Phase. So this affects the type of inverter you will need. More phases therefore mean that your home can get more power from the Grid. A home with a swimming pool might so possibly need it. Other examples are a ducted air conditioning system, or even so a workshop. More load, so more phases.

Not surprisingly, single phase inverter cost less than three-phase inverter. A 3-phase power connection can therefore have a single phase inverter connected. But it’s better to use a 3-phase inverter. A 3-phase inverter has greater capacity and so deals with various power management issues better. Without approval, accordingly the limit of a inverter's input is 5kW or 5000 watts. Whether single or three phase. The amount of panels connected to it, in fact limited to 6650 watts (6.65kW).

If your circumstances permit, you can apply to Energex to increase this, but the process can be lengthy. If you think you have a bigger demand for power, then get in touch with us to discuss the options. Its likely we can still save you quite a lot of money.

MORE ABOUT STRING INVERTERS

String inverter like SMA Sunny Boy or Fronius Primo are the most cost effective option on the market, so they are quite common. However, not all situations are the same, so there are some limitations which we will describe. A string inverter may not be the best choice if you have shading caused by trees and buildings. "Strings" of solar PV are therefore groups facing the same way and angle.”
The inverter therefore transforms the DC power made by the solar panels into AC power. This power is suitable for use by household appliances.

For many years, string inverter technology has proven itself, so though well known, it is not ideal in all situations. A string of solar panels will produce as much power as the lowest performing panel. Shading on panels harms output. And solar panels facing in many directions hence do not work well with a string inverter. Shading from surrounding objects is therefore a likely cause for panels to make less or no power. You could take steps if shade could be a problem at any time of the day or certain months. You could do this by either cutting down the tree or trimming it back. Or mount the panels where there is no shading.

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HYBRID SOLAR INVERTERS

Hybrid inverter do the same thing such as standard string inverter and battery inverter. This inverter can convert the DC electricity into AC electricity that you can then use, and therefore is able to charge or discharge your solar battery bank, if ever connected.

You do not need a battery in fact to install a solar hybrid inverter. The Fronius Symo Hybrid or the Sungrow SH5K therefore are examples. This provides you with the flexibility then to have your system ready for battery installation in the future. Hybrid inverters do carry out two essential functions, therefore they might be less efficient than string or battery inverter .

So while we’re on the subject; is it worthwhile then to buy a hybrid right now?

We would say not to get one just at the present time, if you're not installing batteries right now. So there are a few reasons why we say that. Firstly, a hybrid inverter will cost you a lot more, sometimes double the price. Technology moves fast as you know, so what you buy today may not be the best choice for tomorrow. That's a lot of money hanging around on your wall doing nothing while you wait to connect a battery. So wait until you're ready.

Then another reason is potential compatibility. A hybrid inverters made today may then not suit the battery kit you have chosen in two years time. There are so many competing battery technologies, it’s hard to try and guess which one will rise above the others. Of course we know that lithium technology seems to have the edge now. However, this situation could then change rapidly if a competing technology shows long-term advantage. So it might be best to wait until you're sure.

WHAT ARE BATTERY INVERTERS?

A battery-based inverter converts direct current (DC) from batteries into alternating current (AC). This is therefore at the appropriate voltage and frequency. So hence powering lights and appliances that normally run on power supplied by the power Grid. All Off-Grid systems can in fact use battery inverter. Using net metering, some can also feed power back into the power Grid similar to the common grid-tie inverter. All battery inverter accordingly require a battery storage to function.