Independent Review

Sonnen Solar Battery Review – Are they any good?

Solar Run
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  • Premium 'All In One' Battery Storage System
  • Designed in Germany and assembled in South Australia
  • Industry-leading 10 year warranty

Sonnen Solar Battery Review Australia | Are They Any Good?

Yes, they are good. Our detailed review of the Sonnen Flat battery finds that it is a truly powerful product that can deliver outstanding results. As a consequence of creating a premium product, the premium price tag of a Sonnen battery remains the main limiting factor for Australians. Our buying guide reveals that the cost of a Sonnen Battery in Australia is relatively expensive compared to its competitors. However, with the Energy Bundle options and energy saving potential over the long run, the Sonnen Flat Battery remains a very worthwhile investment.

The biggest benefit of Sonnen Battery is the ‘All In One’ solution. We  recommend Sonnen when performance is the most important consideration and price is not an obstacle. Our Sonnen Battery Review covers Costs, Buyers Guide, State Government Rebates, Inverters and Warranty.

Solar Battery Buying Guide

If you are looking for a high performing battery then you will be looking at a Sonnen Battery. There are a lot of important questions to answer when deciding on the right solar battery option for your home. Our buying guide for the Sonnen Battery will help you with the process. Before you make a decision, first answer these questions:

Are there any State Government Rebates available to subsidise some of the purchase cost?

If so, some State Government Rebates offer interest-free or low interest loans. Check out our article on Victorian solar home rebates for more information.

What is your budget and will that sized Battery be adequate for your home?

If there is no State Government Rebate you will need to spend at least $10,000 to $18,000. In South Australia, Victoria and Queensland you can get up to $6,000 off the cost of the Battery.

What is the return on investment or payback period?

Do your numbers or have Solar Run do them for you. Solar batteries are a terrific long-term investment to save energy costs in the long run. With a premium battery like the Sonnen Flat, the upfront costs are high, so you need to be happy with the payback period.

Do you have an indoor area to install the Battery unit?

It is important to know that installing the Battery outdoors will significantly reduce the lifespan of the Battery Cells. This can greatly impact your return on investment and your payback period, therefore the positioning of the battery in your home should be taken into consideration.

Do you need back-up power?

Installing a 10kWh and above Battery will keep your lighting circuits powered usually until the power returns.

Is your Retailer Clean Energy Council Approved (A CEC Approved Retailer)?

A CEC Approval is an essential credential, as most State Government Rebates make this mandatory. Not choosing a CEC Approved Retailer will disqualify you from the Rebate.

What is Sonnen Flat Energy bundle?

If you have at least a 5kW solar panel system and a minimum of 5kW Sonnen Battery, you are eligible for the Sonnen Flat Energy Bundle. Customers on the bundled plan will only pay a flat fee starting from $30 per month. Whiles its not an unlimited product, the consumption allowance is still enough for the average house not to pay more then the monthly cap. The table below compares the available Sonnen Flat Energy Bundles.

Sonnen Battery Energy Bundle

About the company

Sonnen is regarded as one of the top Energy Storage Manufacturers in the world and were recently acquired by Shell.  They are renowned for their quality product engineering and market-leading warranties. Sonnen believes that it is already possible to economically produce clean energy at home today. What started as an idealistic idea, Sonnen has become one of the biggest producers of intelligent energy storage systems. The headquarters of Sonnen is in Wildpoldsried. A Bavarian village that is already running on 100% renewable and clean energy. Sonnen announced in 2018 that it will be opening an assembly facility in the former Holden factory located in Adelaide.

Sonnen Battery’s are widely installed in South Australia. They also offer a Virtual Power Plant option called sonnenFlat. While they are commonly written as Sonnen, they themselves prefer to not to capitalise the S (sonnen).

  • 40,000 installed systems
  • Founded in 2010

Our analysis of the Sonnen Battery

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Our report of the Sonnen Battery (Batterie)

Are they fit for Australian conditions?

Yes. All of their batteries are clean energy council approved. Widely sold in South Australia Sonnen provides market leading batteries. Here in Australia we get very cold temperatures in Winter. In summer we get very hot temperatures. Based on our review we recommended that solar batteries are keep away from direct sun. Sonnen batteries have a wide range of operating temperatures.

Will it be compatible with your Solar Inverter?

Yes. The Sonnen Battery is AC coupled and is compatible with most CEC Approved Solar Inverters. This is only important when adding Solar Battery Storage to an existing system. On a new Solar and Battery installation there is no need for an additional Inverter. The reason for this is the Sonnen Battery System has an in-built Inverter. This will make the installation very neat and tidy.

How much does a Sonnen Battery cost?

The price of a Sonnen Battery in South Australia, Victoria and Queensland is reduced thanks to additional State Government Rebates. The rebate can cut the costs of the battery storage in half. This rebate therefore makes the Sonnen Battery significantly more affordable. For other states, the cost of a full price Sonnen Battery could be up to $18,000 installed. Sonnen prices are more expensive than some other leading Solar Battery Providers. What you get for the extra cost is a powerful and reliable German-Engineered Battery Storage System.

Are Sonnen Battery’s VVP (Virtual Power Plant) ready?

Yes, based on our Sonnen Battery Review. In some State Government Rebate Schemes its mandatory. The South Australia Home Battery Scheme requires all approved products to be VPP ready. Sonnen batteries are a great choice if you are considering signing up to a VPP (Virtual Power Plant). A VPP allows many solar systems to act together as a power plant. Collectively a VPP can then store power when it is cheap and sell it when the price is higher. The bigger the VPP the bigger the buying power. VPPs are not yet common but being “VPP ready” is an important consideration. Sonnen runs their own VPP system called sonnenFlat (available in South Australia).

Are they expandable?

No. Based on our Sonnen Battery Review, its not recommended. Battery Storage Systems are a large investment. Get the right system from the beginning. After all its a 10 + year investment. The Sonnen Battery is an All In One system so adding another unit in future years might be problematic.  Sonnen have 3 Battery Storage Cabinets. The 67cm x 88cm cabinet is the smallest in size and capacity. It typically has 5kWh of electricity. The 67cm x 137cm cabinet typically stores between 5kWh to 10kWh of electricity.The largest cabinet is 67cm x 137cm and typically stores between 5kWh to 15kWh. Do you homework and choose the right sized Battery Storage System for your home and budget.

Will the Sonnen Battery operate in the event of a black out?

Yes, but its usually an extra cost. It is available as an added extra from the manufacturer but it isn’t a requirement as black outs across major cities in Australia are few and fair between. If you do require battery back up, its worth working out how long you need battery back up for vs how long will the battery storage system will keep you running for.

Can the Sonnen Battery be installed on a 3 Phase Home?

Yes. The All In One Battery is typically installed on a Single Phase home. You can also install Single Phase Battery on a 3 Phase home. The Battery Storage System connects to 1 Phase of your home. This will allow you to install multiple Batteries in your home. Speak to Solar Run for advice on the best solution for your property.

The Verdict

Our comprehensive review of the Sonnen Battery finds that it is one of the leading solar battery products on the market. Sonnen is a well-known company that produce powerful, efficient energy solutions.

The Sonnen Flat Battery’s reliability and power far outweigh the cost of the product. The German-engineered energy storage solution will provide a strong return on your initial investment. By empowering your home with an industry-leading battery to retain and deliver solar power, you will reap the financial and environmental benefits of renewable energy.

While a cost analysis of the Sonnen Flat is valuable to customers, many will also appreciate the sleek design of the battery. The slender frame means the battery will easily mount onto a wall without ruining the aesthetic of your home. Customers in those states with Government Rebate options will find even more reason to invest in a Sonnen battery.


There are a lot of options on the market, so do you research, check out other products and assess your options.

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