Solar Inverter

A fundamental part of every Solar Power setup is the Inverter. It is a piece of equipment that is very important to understand.

After you read this definitive guide, you will understand:

Chapter 1

What is an Inverter?

The basic fundamentals

An Inverter plays a very important role within a Solar Power or Load Shedding Kit.

Simply put, a solar inverter converts DC power (Direct Current) that Solar Panels produce and batteries store into AC power that our home appliances use to run.

Inverters do several other things like tracking your production, and they are responsible for ensuring your system is safe and shutting down if it’s not to prevent damage.

Without an Inverter, you can't use the Solar Power your panels are producing.

Hybrid string inverter

Understand the Basic Inverter Types

Watch our short video to understand which type will be best for you

Chapter 2

Hybrid Inverters

How do they Work?

The energy from your Solar Panels or your Batteries is fed to the inverter, which then, in turn, handles that energy by transforming the DC power to AC.

You get three main types of Inverters you can use. Each one functions a bit differently from the other: Grid-Tied, Off-Grid & Hybrid Types.

Features

  •  Newest Technology 
  • Multiple MPPT inputs
  • Scalable
  • Flexible
Hyrbid kit diagram

Understand how Hybrid Inverters Work

Watch our short video to understand how the Hybrid inverter works

Each inverter has their own set of requirements:

New Technology

The  newest in inverter technology , the Hybrid Inverter offers everything you'd need in an inverter and then some.

Multiple MPPT Inputs

Most Hybrid inverters will come with  two or more MPPT inputs  and a  high voltage range , allowing you to have a more extensive array. In addition, you can  split your array  so that you have two arrays that function independently. Separate arrays mean that should one fail, you still have another fully functioning array.

Scalable

The Hybrid Inverters can be paralleled, which is an excellent feature if you plan on scaling up in the future. They communicate with most Lithium-ion Batteries, and most Li-ion batteries are parallalable too. Above all, If you need a  system that can grow with you , this is most definitely the inverter to go for.

Flexible

Another great feature of the Hybrid Inverter is the ability to  power non-essential loads  should your solar power production exceed the needs of your essential load. To clarify, this means that any  extra solar power produced can then be used for your non-essential appliances .

Finally, the feature that makes the Hybrid Inverter genuinely exceptional is the ability to  blend power from multiple sources .

It will always use the available solar power generated from your array, and if your array is not producing enough, it will  pull power from your batteries and the Grid . This feature ensures that you always have power and that you use the available solar-generated power first and foremost before using your batteries and the grid.

The Fusion inverters are the ideal Hybrid inverters, and we highly recommend these.

Pros

  • Efficient
  • Easy to install
  • Blends AC/DC Energy
  • Long-lasting (around 15 years)

Cons

  • More expensive
Chapter 3

Off-Grid Inverters

The inverter that brought everything together

Features

  • Easy to install
  • Expandable
  • High or low voltage options
  • Lowest solar inverter price

A very  popular choice because of their price , compared to previous Off-Grid inverters, they are far easier to install due to the fact you have everything in one box instead of separate components.

Off-grid kit diagram
However, in previous years, an Off-Grid inverter was simply a metal box that only had one function: convert DC to AC.

You would need other components like an MPPT (this allows you to connect to solar panels), a Charge Controller (that allows you to connect to batteries), a monitoring device, and a bunch of wiring to tie it all together. Now, you get all of this in one box!

A Quick Guide on Off-Grid Inverter

Need to understand Off-Grid in a nutshell?

Expandable

 Some Off-Grid inverters can be paralleled  should your demand for more power increase. But, it is essential to remember to do your research and ask questions about how to meet your needs and future plans.

High or Low Voltage

You get  2 main types of Off-Grid inverters, and these are Low-voltage and High-voltage . The difference between the two comes down to how many solar panels you can connect to the inverter, more detail on how that worksin this guide.

Pros

  • Easy to install
  • Expandable and modular
  • Affordable

Cons

  • Less reliable than a Hybrid
  • Lifespan isn't that great (around ten years)
  • Can be noisy
Chapter 4

Grid-Tied Inverters

Feeding back to the grid

Features

  • Grid connection required
  • Solar Panels required
  • Scalable
  • No batteries

Grid-Tied Inverters require an active grid connection to function. If the grid goes down, you will not be able to use any Solar Power produced. An energy meter must be installed within a Grid-Tied Kit so that should your array not be producing enough solar power, it will supplement the excess with grid power.

Grid-tied kit diagram
Another feature of the Grid-Tied inverter is that you can feed Solar Power back into the grid. However, there are additional charges for this ability including the cost of a bi-directional meter, installation and a daily fixed charge or around R12.
Grid-Tied setups are ideal for homes or businesses that use the majority of their electricity during the day. Supplementing your daily electricity usage with Solar Power will drastically reduce electricity bills.

Grid-Tied systems do not require batteries which brings down the cost of these kits.

Chapter 5

What Size Inverter Do I Need?

Working out what size inverter you'll need is easy

Here is the formula that we use at SolarAdvice to calculate system sizes for our clients. It will help you work out what inverter size you'll need and you'll understand how solar inverter sizing works.

All you'll need to work out which inverters size is best for you is your average monthly electricity bill and a calculator.

Different size inverters

Step 1

Take your average monthly electricity bill amount and divide that by 2.2 (the average price per kW) Eg:

Monthly Bill

R1800

/
Average Price Per kW

R2.20

=
Monthly Usage in Kw

818.18kW

Step 2

Take your monthly usage in kW and divide that by 30 (days in a month)

Monthly Usage in Kw

818.18kW

/
Days in a Month

30

=
Daily Usage in kW

27.27kW

Step 3

Take your daily usage and divide it by 5.5 - the hours in the day that you produce the most.

Daily Usage in kW

27.27kW

/
Max Production Hours

5.5

=
Production Needs

4.96kW

Inverter Sizing Conclusion

You will need at least a 5kW inverter to cover the 4.96kW

  • 6 x 400W Solar Panels = 48% coverage.
  • 10 x 400W Solar Panels = 81% coverage.
  • 12 x 400W Solar Panels = 97% coverage.

Important Array Sizing Information

In addition to size, you will also need to consider MPPT voltage ranges when selecting an inverter.

Do you need a large array? If the answer is yes, you will need a high voltage inverter.

If the answer is no, you can look at the low voltage inverters.

You can read up more on how to size an array here: How to Size a Solar Panel Array
Bonus Section

Inverter Application Questions

These are the questions you should ask yourself before choosing an inverter.

Do you want an inverter for solar power or load shedding only?

If you answered Solar Power, a Hybrid Inverter is recommended because it synchronises to the grid allowing you to use all available Solar Power and if you’re not producing enough, it will pull the deficit from the grid and/or batteries.
If you answered load shedding, either-or will do nicely.

Will you add solar panels later?

Adding Solar later is something that many of our customers do. However, in this instance, it is always a good idea to install a Hybrid Inverter because of its blending capabilities mentioned above. Installing a Load Shedding Kit now and installing Solar Panels later, breaks up the cost of the product and installation allowing you more time to prepare financially.

Will you add extra solar panels later?

If you’re wanting to add extra solar panels later, an inverter with more than 1 MPPT is your best option. Allowing your system to grow with you.

Will you need batteries?

If you’re adding batteries, check to make sure that the inverter you are interested in is compatible with the batteries you want.

Will you be adding another inverter later?

Some inverters can be paralleled and some can’t. Be sure to check the datasheet or ask one of our sales team.

Do you require a UPS function?

If you're running life-saving machinery or computers, you’ll definitely want to invest in an inverter that has UPS capabilities.

Do you have Single Phase or 3 Phase supply?

This will determine the type of inverter you will need. You can install a single-phase inverter on each phase if you have 3 phase supply. Or, there are 3 phase inverters available on the market.

Chapter 6

Solar Inverter Prices

What to expect

The cost of a solar inverter all comes down to brand, build quality, features, and size.

For commercial inverters that have a massive kW rating, you will be paying anywhere from around R50,000 and much higher for even larger inverters.

Whereas residential inverters typically starting from a 3kW to a 10kW inverter, you can expect the following price ranges:

Off-Grid Inverters

Between R 8,000.00 and R 14,000.00

Hybrid Inverters

Between R 18,500.00 and R 44,000.00

Whatever the choice, it's always best to start where you can, saving you money in the long term and having the ability to re-jig your system as time goes on.
Chapter 7

Best Solar Inverters in South Africa

Quality inverter brands

To name the best pound for pound brand is tricky. Each brand does have its strengths and weaknesses, depending on its application.

Here are the best brands that we would recommend:

Fusion Solar logo

Fusion Solar

Fusion Solar's creators have seen the demand in South Africa for more choice when it comes to Solar Inverters and Batteries.

Passion for the South African Solar Industry has seen them answer this demand by bringing in products fit for the South African market.

Top features:

  • Stylish
  • Functional
  • Reliable
  • High Quality
  • Excellent warranties
Additionally, their products are specifically chosen for their price point and size to be able to cope with long periods of no grid supply and compatibility with quality products from other suppliers.

Their Solar Products have been popular thanks to their reliability and stylish design.

View Fusion Solar website


Alpha ESS logo

AlphaESS

Founded in 2012, AlphaESS is one of the leading energy storage manufacturers in the world.

Their passion for green energy is evident in their excellent product range. AlphaESS offer a variety of residential and commercial solar solutions in over 60 countries worldwide.

Top features:

  • Good reputation
  • Long life-span
  • Excellent quality
  • Great support

Additionally, AlphaESS ranked fifth as one of the top suppliers of Residential Storage Systems for 2020, accounting for 15% of the global market share.

View AlphaESS website


Goodwe logo

GoodWe

GoodWe's hope for a sustainable future for the generations to come has seen them produce some of the worlds best quality inverters and as such, they have won numerous awards for their outstanding products.

And as a testament to their hard work, they were listed as a public limited company on the Shanghai Stock Exchange in 2020.

Top features:

  • Excellent reputation
  • Innovative
  • Superb quality
  • Great warranties
With a passion for technological innovation, there is no doubt that GoodWe will continue to grow from strength to strength and reach more homes in South Africa.

View GoodWe website


Sofar Solar logo

Sofar Solar

Sofar Solar has been sharing its exciting new products with the world since 2013.

They have been one of China's top 5 string inverter manufacturers for many years and have supplied their products to over 80 countries worldwide.

Their excellent price point offers many South Africans the chance to own a Hybrid Inverter.

Top features:

  • Worldwide availability
  • Reliable and safe
  • Quality products
  • Good warranties
View Sofar website


Resources:

https://en.wikipedia.org/wiki/Solar_inverter

3 comments

  1. Anonymous

    Visitor Rating: 4 Stars

  2. Visitor Rating: 5 Stars

  3. Nikola Batev

    Good day,
    I would need some advice and pricing.
    In January i bought 16 365W solar panels, 3kVA RCT 48V Inverters x 3 and four Pylon-Tech U 2000 batteries.
    During the installation ALL three inverter did blow up – incorrect installation by some company from Brakpan – CHC Electrical. So – now I am looking for the new inverters. I wold like to go for 5kVA – two f them. I would need a quote from you and advice – which ones can I install, how many solar panels can they take and – most important – can I split the system in two – one 5kVA + 2 Pylon Tech batteries and join them…or would you advise something else.

  4. Hi

    Sorry to hear about the inverters blowing up, your choice of 5kVa inverters sounds like a better option but before suggesting anything what kind of appliances/machines are you running and what is the maximum kW’s are you dealing with?

    If you’re looking for high end inverters that handle large loads and spikes we suggest the Victron inverters, if however you are dealing with moderate loads and spikes we’d would suggest an inverter from our Hybrid range or for the lower end of the end we suggest the Kodak (Voltronic) range.

    Thankfully you have PylonTech which are a good brand with a decent compatibility range.

    Give us a call or email us to advise further.

  5. Anonymous

    Visitor Rating: 4 Stars

  6. Visitor Rating: 4 Stars

Comments are closed.

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