October 23, 2023

Tesla Powerwall vs sonnenBatterie Evo - Which solar batteries should you buy?

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When buying a solar system for your home, you might consider purchasing solar batteries to store excess energy. This allows you to charge with the sun's energy during the day and helps power your home in the evening. This is most effective when you and your family are working or studying during the day, but spend most of your energy at night.

Two brands that sell solar batteries are Tesla and sonnen. Both are great products, and have similar specs.

But the most imporatnt part (if you're Australian) is that Sonnen products are manufactured locally in South Australia.

Who is Sonnen and what is the sonnenBatterie Evo?

Sonnen is a global leader in smart solar battery storage, offering solutions that protect consumers from rising electricity prices and promote energy independence. Their products, such as the sonnenBatterie Evo are German-designed and engineered solar batteries that store cleaner energy generated from rooftop solar systems for use day or night. Sonnen's vision of a future of clean and decentralised energy supply has been recognised with several awards, including EuPD Research Australia's Top Brand PV Storage and the German Sustainability Award Design 2021. They are committed to helping homes become more energy independent and offer a partner network for those interested in their products and services.

For Australians more importantly, Sonnen manufacturers their batteries locally. In 2018, Sonnen opened their plant in the historic Holden Plan in Elizabeth, South Australia, and has been innovating and serving Australians from there ever since.

The product we're talking about today is the sonnenBatterie Evo.

Specification Sonnen Evo
Nominal Voltage (AC) 230 V
Nominal Frequency 50 Hz
Rated Active Power 5000 W
Rated Output Apparent Power 5000 VA
Rated Output Current 22 A
Power Factor Range 0.5 leading … 0.5 lagging
Grid Connection Single-phase, L / N / PE
Nominal Voltage (DC) 204.8 VDC
Battery Voltage Range 160 - 230 V
Nominal Capacity / Usable Capacity 11 kWh / 10 kWh
Max Charge / Discharge Current (continuous) / Max Power 40 A / 5 kW
Cell Chemistry Lithium Iron Phosphate
Dimensions (W x H x D) 710 mm x 1400 mm x 427 mm
Installed Weight (approximate) 163.5 kg (Cabinet 74 kg, Battery Module (each) 40 kg, Plinth 9.5 kg)
Ambient Temperature Range -5 ⁰C to 45 ⁰C
Max. Relative Humidity 90 %, non-condensing
Permissible Installation Altitude 2,000 m
Inverter Efficiency 94.4 % peak
On-grid Pass-through 35 A

Who is Tesla and what is the Powerwall?

Tesla is a pioneering company accelerating the world's transition to sustainable energy. They produce electric cars, solar products, and integrated renewable energy solutions for homes and businesses, aiming to reduce global dependence on fossil fuels.

The Tesla Powerwall is a home battery system designed to store energy from solar or the grid, providing power during the night or during power outages. It automatically becomes your home's energy source when the grid goes down, keeping your lights on and phones charged without the need for upkeep, fuel, or noise. When paired with solar panels, it can recharge with sunlight, keeping your appliances running for days.

With the Tesla app, you can monitor your home’s energy production and consumption in real-time, set your preferences to optimise for energy independence, outage protection, or savings, and receive instant alerts and remote access.

The Powerwall is designed with a minimalist aesthetic that complements a variety of home styles. Its compact, all-in-one construction features versatile mounting options for indoor or outdoor spaces and has a warranty of 10 years.

Here is some data about the Tesla Powerwall.

Specification Tesla Powerwall
AC Voltage (Nominal) 230 V
Total Energy 14 kWh
Usable Energy 13.5 kWh
Round Trip Efficiency 90%
Warranty 10 years
Operating Temperature –20°C to 50°C
Ingress Rating IP67 (Battery & Power Electronics), IP56 (Wiring Compartment)
Wet Location Rating Yes
Noise Level @ 1m 40 dBA at 30°C
Dimensions 1150 mm x 753 mm x 147 mm
Weight 114 kg
Mounting Options Floor or wall mount
Certifications IEC 62109-1, IEC 62109-2, IEC 62619, UN 38.3

Similarities between the Tesla Powerwall and sonnenBatterie Evo

Here are some similarities between the two products:

Specification Both
Rated Active Power 5 kW
Battery Chemistry Lithium-ion
Warranty 10 years
Ingress Protection Outdoor rated
Coupling AC-Coupled

Usable Total Energy Capacity

Usable energy capacity looks at the total amount of energy that can be used. There will be a listed nominal output which represents the maximum amount of energy that can be used. In practice, this will never be 100% due to other factors affecting the actual power output. Looking at a battery’s depth of discharge helps you see how much energy you would be receiving in practice.

Tesla’s Powerwall 2 battery has a stated usable energy capacity of 13.5 kWh with a depth of discharge at 90%. This means the usable energy would actually be 12.15 kWh. The sonnenBatterie EVO has a usable energy capacity of about 10 kWh.

Instantaneous Battery Power

Battery power looks at the maximum amount of power that a battery can discharge at once. How much power is actually drawn from the battery is dependent on device usage. But if you try drawing more power from your battery than it can put out, you won’t power all of your devices.

Both batteries can deliver up to 5kW.

Of course, they are both modular, which means you can have more than 1 at a time. This will increase both the total energy capacity as well as the instantaneous battery power.

System Expansion

If your energy needs grow, you must expand your energy storage to keep up with the additional requirements. Solar batteries can always be added to an existing system, but you should be aware of how easy it is to add new batteries. That gives you an idea if it is worth saving up for a large expansion or using smaller expansions as necessary.

Both are modular and can be increased in size depending on your requirements.

Benefits to the community

Some solar battery companies can offer additional benefits t;sllo help you make the most of your battery system. These provide incentives for purchasing that company’s products such as extending product warranty or earning more from solar feed-in tariffs.

Tesla has the Tesla Energy Plan, which is a virtual power plant that lets you supply your community with solar energy while drawing more power from it as necessary. This extends your Powerwall warranty by five years, while letting you earn Powerwall credits on a new battery system.

sonnen has sonnenConnect, which provides daily rewards in addition to your existing solar feed-in tariff. As long as your solar battery has a capacity of at least 4 kWh, you can participate to get daily rewards while staying with your current energy retailer. There is a $100 sign-up bonus and you can leave the program at any time.


Monitoring your solar battery’s performance is crucial to ensuring you have enough power. Knowing your battery’s current power levels and output will help you see where the energy is going. It also helps you catch potential problems, like a device draining too much power or panels not providing enough energy.

Tesla’s mobile app monitors the performance of all Tesla products you use. You can see how the Powerwall battery, solar, and grid connections work together. There are also menus to check your energy usage and the time your solar system is producing power. You also get information such as energy taken from the grid if solar isn’t providing all of your power needs.

sonnen’s app (the sonnen App) monitors your solar battery and its connection to the rest of your solar system. Solar power generation, usage, and the current status of the system are given to you. It’s also linked to sonnenConnect, helping you see how your participation in the program is benefiting your battery.


The prices of both batteries are very similar, and they can be found between $10,000 to $12,000 AUD installed.

Why Sonnen may be more suitable for you

As you can tell, the sonnen and Tesla Powerwall are quite similar in terms of cost, features.

But if you're in Australia, especially South Australia, supporting a locally produced and manufacturered product is far better for our community and economy.

You may be surprised at how quickly prices have come down recently. Depending on your load profile, you may find that batteries return on investment could be a lot faster than you initially though.

Go Sunny Solar offers a Powershift Battery Plan that helps you get your batteries installed with a $0 upfront cost. You will repay the cost of the battery with interest free payments, letting you see the benefits of energy storage immediately. Contact us today to find out more.

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