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Detailed reviews and information of the best solar panels, inverters and batteries. Plus hybrid and off-grid solar system reviews and information articles on how solar and battery systems work.

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Reviews and information on the best Solar panels, inverters and batteries from SMA, Fronius, SunPower, SolaX, Q Cells, Trina, Jinko, Selectronic, Tesla Powerwall, ABB. Plus hybrid inverters, battery sizing, Lithium-ion and lead-acid batteries, off-grid and on-grid power systems.

Best Solar Battery systems 2021

Jason Svarc

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Home energy storage batteries have been on the market for many years with numerous varieties and sizes now available. Due to the rapid improvements in lithium technology, modern lithium battery systems quickly superseded traditional lead-acid batteries as manufacturers developed smart, modular systems to suit different energy storage applications. The vast number of battery options is great for consumers but it has made it more difficult to select the best battery to suit a particular home or business. If you are new to solar, read our introduction to battery storage, including the pros and cons of home batteries.

Unfortunately, the one-size-fits-all approach is often taken when it comes to sizing a battery which can lead to poor system performance. This is typically due to two main reasons:

  • Undersized batteries - batteries that don't have adequate capacity to meet the household demand.

  • Oversized batteries - when the solar array doesn’t have sufficient power to charge the battery, typically during the winter months.

To avoid these issues a battery should be selected according to a number of important factors including; solar array size (existing or new), system type (on-grid or off-grid), and most importantly, average daily energy consumption (kWh). With this in mind, we selected the best batteries according to the six following categories:

Best Solar battery systems

  1. Sungrow SBP4K8 - Best small battery up to 5kWh

  2. LG Chem RESU10 - Best mid-size battery up to 10kWh

  3. BYD Premium - Best modular battery system

  4. Tesla Powewall 2 - Best AC coupled battery system

  5. Powerplus Energy - Best off-grid battery system

  6. Redback Smart Hybrid - Best all-in-one solar battery system

Before going into detail about the best battery systems, we will first explain some key differences between the various battery types and why certain batteries are better suited to different applications. It is worth noting that most of these battery systems require a compatible hybrid inverter to operate.

Below is the complete list of all the battery systems in our review

Click to see the detailed solar battery comparison chart with full specifications, sizes and costs.

Click to see the detailed solar battery comparison chart with full specifications, sizes and costs.

Battery Capacity - kWh

Battery size or capacity is measured in kWh (kilowatt-hours). This is the amount of energy a battery can store, although the usable capacity may differ from the total battery capacity. For example, a lithium battery with 10kWh total capacity, may have its usable capacity limited to 80% to increase lifespan. Therefore, only 8kWh of energy can be discharged on a daily basis. However, often the last 20% is available in emergencies, such as a prolonged blackout.

The new solar and battery sizing tool shown below can help you quickly and easily calculate the optimum size solar and battery system for your home.

The free, simple  solar and battery calculator  helps determine the best size battery system for your home

The free, simple solar and battery calculator helps determine the best size battery system for your home

The life of a battery is generally determined by the number of charge/discharge cycles (or total energy output). All batteries lose capacity over time, and the end-of-life is generally after a battery has lost 20 - 30% of its original capacity, which is typically after 3000 to 3500 cycles, or roughly 9-12 years.

For those new to solar, see our basic introduction to different types of solar systems including grid-tie, off-grid and hybrid battery systems. For those looking for a comparison between lithium and lead-acid batteries see the complete solar battery review or the Lithium Vs Lead-acid article.


Different types of lithium batteries

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Selecting the best battery is difficult due to the many system types or configurations available, each with different performance characteristics. Another layer of complexity is the compatibility issue - many lithium batteries are designed to work with a specific type of hybrid or battery inverter to suit certain applications. For example, some batteries like the high voltage (HV) versions, can only be used with a HV compatible hybrid inverter, while others such as the Tesla Powerwall 2, are AC coupled batteries utilising inbuilt inverters which enable them to be retrofitted to a home with an existing solar system. Then there are modular, rack-mount battery systems which can function with a wide variety of high-performance off-grid inverters.

With this in mind, selecting the best battery is not straightforward as all battery systems need to be judged on a wide range of criteria including:

  • Usable storage capacity (kWh)

  • Output power rating

  • Efficiency - charge & discharge losses

  • Cycle life - capacity loss over time

  • Inverter and system compatibility

  • Operating temperature range

  • Cost (including inverter)

  • Warranty conditions.

This might sound overwhelming, but luckily we have done the hard work for you and gathered feedback from many experienced solar professionals to determine the best battery for each application.


Best solar battery up to 5kWh

1. Sungrow SBP4K8

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The compact Sungrow SBP4K8 battery is one of the most underrated batteries on the market due to being a re-packaged version of the high-performance Samsung SDI battery.

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Samsung is one of the world’s leading battery manufacturers with a long history in battery manufacturing. Samsung engineered the SDI module utilising a stack of high-performance Lithium NMC prismatic cells with a design life of 6000 cycles or around 15 years. The unique prismatic cell design includes advanced safety features and a layered structure (not wound) to increase cycle life and improve reliability. Performance (of the older version) has shown very good results so far in the independent ITP renewables battery testing.

Sungrow Battery specifications

  • Type: DC battery system - Samsung lithium NMC cells

  • Size: 4.8kWh with 95% usable capacity

  • Power output - 2.5kW continuous, 4kW max peak

  • Cycle life: up to 6000 cycles (claimed)

  • Price: approx $4000

  • Warranty: 10 years

  • Compatibility: Sungrow Hybrid inverter SH5K-20 & SH5K-30

The Sungrow SBP4K8 battery is very affordable coming in at around $4000. It’s also very compact with convenient grab handles moulded into the sturdy cast-aluminium lid. There are cable entry points on either side of the battery making it much easier and neater to install and enabling multiple batteries to be easily connected in parallel for greater storage capacity if required (up to 14.4kWh). Weighing in at 48kg, it can be wall or floor mounted and features a single round led light to indicate the operating status. See Sungrow SBP4K8 data sheet.

Q cells Q.Save 4kWh battery

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Considering several other manufacturers have also repackaged the high-performance Samsung battery packs, we decided to give a special mention to the new Q cells Q.SAVE-G2 4 kWh battery system. The Q cells battery is part of the recently released Q.Home Energy storage system which is a unique scalable home battery system built around the Q.Home hybrid inverter. The clever modular design hides the cable interconnections and is able to be expanded up to a maximum capacity of 12kWh using three of the battery modules. See the full Q cells Q.Home ESS specifications.

Runners up - Other battery options


Best solar battery up to 10kWh

2. LG Chem RESU 10

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Lg Chem RESU10H (400V)

Lg Chem RESU10H (400V)

The wide range of RESU (residential energy storage unit) batteries by the leading south Korean battery manufacturer LG Chem are definitely one of the most popular home batteries in the world. Featuring high-performance lithium NMC pouch cells, the RESU10 (9.8kWh) battery is available as either a common 48 Volt battery, or as a high voltage 400V RESU10-H battery. The high voltage option is more expensive but still reasonably well priced at around $8500. It is also larger in size and compatible with many of the leading hybrid inverters including the popular SolarEdge StorEdge and new generation SMA Sunny boy storage (SBS). See the detailed LG Chem RESU battery review.

LG Chem Battery specifications

  • Type: DC battery system - Lithium NMC pouch cells

  • Size: 9.8kWh with 90% usable capacity, (expandable to 19.6kWh)

  • Power output - 5kW continuous, 7kW peak

  • Cycle life: up to 4000 cycles (claimed) - Ref warranty doc

  • Price: approx $7500 (48V), $8500 (400V)

  • Warranty: 10 years - Ref warranty doc

  • Compatibility: SMA, SolarEdge, Fronius, Sungrow, Huawei, +more

LG Chem RESU10 - Compact 48V version

LG Chem RESU10 - Compact 48V version

As opposed to many other manufacturers which use cylindrical or prismatic battery cells, LG chem use a unique Polymer 'pouch' flat laminated cell design which they claim enables higher energy density and increased reliability. Layering the battery cell sections rather than rolling or bending the cell structure also reduces the likely-hood of failure. Independent testing by ITP renewables has shown very good performance and the many thousands of batteries installed around Australia and the world have proven the RESU range to be a solid reliable choice with very good overall feedback. The only known issue is the automatic shutdown response which occurs in the event of a communication interruption with the inverter. This can be frustrating but it is a good safeguard.


Best modular battery system

3. BYD Premium HVM & HVS

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BYD is a massive China-based battery manufacturer that has launched into the electric vehicle and energy storage market. BYD offers a wide variety of Lithium battery system based on LFP or Lithium Ferro Phosphate cells due to the increased safety, stability and lifespan compared to other lithium chemistries. BYD pioneered the modular, tower battery concept with the first generation high-voltage (HV) battery system launched back in 2017. This unique design was in response to the new HV hybrid inverters being developed which offered increased efficiency and lower manufacturing costs associated with the new voltage power conversion inverter architecture.

BYD Premium HVM Battery specifications

  • Type: DC battery system - Lithium LFP prismatic cells

  • Size: HVS = 2.56kWh (100%) usable - expandable to 38.4kWh

  • Size: HVM = 2.76kWh (100%) usable - expandable to 66.2kWh

  • Power output - HVM = 2kW per module, HVS = 2.5kW per module

  • Cycle life: up to 3000+ cycles (claimed) - Ref warranty doc

  • Price: approx: HVM = $870 per kWh, HVs = $935 per kWh,

  • Warranty: 10 years to 60% min retained capacity. Ref Warranty document.

  • Compatibility: SMA, SolarEdge, Fronius, Sungrow, Growatt.

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The BYD HV Premium series is a high-voltage modular tower battery system available in two voltage options designed to cater for different energy storage requirements. The battery modules are stacked and connected in series to increase the battery system voltage from a minimum of 200V (2 x HVS modules) up to a maximum of 5 modules. The HVM requires a minimum of 3 x 50V modules (150V) up to a maximum of eight. Note, the two battery variation cannot be used together.

Runners up - Modular battery systems

There is a growing number of high-performance modular, stackable battery systems now on the market such as the PylonTech Force battery system and the recently released Huawei Luna2000 battery.

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Best AC coupled battery system

4. Tesla Powerwall 2

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The first Tesla Powerwall was widely known as the battery that kick-started the home energy storage revolution. However, it wasn’t until the Tesla Powerwall 2 was released in early 2017 that it really hit the mainstream. The Powerwall 2 is more expensive than most, coming in at around $10,000, but considering the large amount of usable storage capacity (13.5kWh) it’s still good value for money. Unlike the other batteries listed, the Powerwall 2 is an AC battery system, meaning it contains an integrated inverter/charger and can be retrofitted to any home with an existing solar installation. However, it still requires a solar inverter to function with a solar array. Furthermore, to enable backup power in the event of a blackout, an additional Tesla gateway box is required which adds around $2,000 to the price but also enables many ‘smart’ features & monitoring.

Tesla Powerwall Battery specifications

  • Type: AC battery system - Lithium NMC cells

  • Size: 13.5kWh with 90% usable capacity

  • Power output - 5kW continuous, 7kW peak

  • Cycle life: approx 3500 cycles (claimed) - Ref warranty doc

  • Price: approx $10,000 + backup gateway

  • Warranty: 10 years - Ref warranty doc

  • Compatibility: Any solar inverter (AC coupled)

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The Powerwall 2 uses high quality lithium nickel-manganese-cobalt (NMC) cells developed in collaboration with Panasonic. It also features a clever liquid thermal cooling system making it one of the advanced stationary batteries systems in the world. The liquid-cooling allows a wide operating temperature range (-20 to 50 degC), meaning it is less likely to derate (reduce output) in high ambient temperatures and extremely low temperatures. Furthermore, it has a very high weather rating (IP56), meaning it can safely be installed outside. The Powerwall 2 also has the capability to work in parallel with up to 9 units (3 per phase) for homes/businesses with greater energy storage requirements.

Runners up - AC battery systems

There are several other very high-quality AC battery systems including the well known Sonnen ECO system which is manufactured in both Australia and Germany, and the Senec Home system which is also manufactured in Germany.

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Best off-grid battery system

5. PowerPlus Energy LiFe Premium

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Based on direct experience and feedback from many professional off-grid designers and installers, the self-managed lithium batteries from Powerplus Energy in Melbourne, Australia stood out as the best and most reliable choice for off-grid solar systems. Unlike many of the common managed** lithium battery systems on the market from manufacturers such as BYD and LG Chem, self-managed lithium battery systems do not suffer from communication issues and are compatible with virtually all leading off-grid multi-mode inverters. They can also be used as a drop-in replacement for older lead-acid battery banks and in certain situations, the battery modules can be ‘hot-swapped’ or replaced without shutting the down site if there is an issue.

**Some managed lithium battery options which rely on communications can be problematic, especially at low state of charge and very low temperatures.

Powerplus Energy Battery specifications

  • Type: DC ‘self-managed’ battery system - Lithium (LFP) cells

  • Size: 3.3kWh with 100% usable capacity (80% DoD for warranty)

  • Power output - 3kW continuous, 3.3kW peak (per 48V module)

  • Cycle life: 3000 to 5000 cycles (based no DoD)

  • Price: approx $3,500

  • Warranty: 10 years

  • Compatibility: Most 24V, 48V, or 120V off-grid or hybrid inverters

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The modular lithium batteries from Powerplus Energy feature high-performance lithium Ferro phosphate (LFP) cells which are widely known as the longest-lasting and most stable battery chemistry, backed by a 10 year warranty from a local, reputable manufacturer. Being Australian based with relatively low volumes, they are not yet widely available, however, production volume is increasing with the larger manufacturing facility now in operation.

Other off-grid lithium battery options

As yet, not all regions have access to the Powerplus Energy batteries but there are several other high-performance, self-managed lithium (LFP) batteries available. In North America, Simpliphi and Discover AES batteries are very well regarded, while GenZ is another option in Asia and Australia.

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Learn more about off-grid batteries in our off-grid solar system review.


Best all-in-one system - BESS

6. Redback Tech Smart Hybrid

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Redback Technologies is an Australian company focused on developing smart, integrated, hybrid energy storage systems for homes and businesses. The first generation smart hybrid system was released back in early 2016, while the Gen 2 system was introduced in 2018. Redback teamed up with the University of Queensland along with the well established Chinese inverter manufacture Goodwe to deliver a quality, feature packed energy storage system at an affordable price.

Redback Battery specifications

  • Type: All-in-one BESS - Pylontech Lithium LFP

  • Size: 11.4kWh with 80% usable capacity (20% reserve)

  • Power output - 5kW continuous, 7.5kW peak

  • Cycle life: approx 3500 cycles (claimed) - Ref warranty doc

  • Price: approx $10,500

  • Warranty: 10 years - Ref warranty doc

  • Compatibility: N/A

The system is built on the well known Goodwe ES hybrid architecture and features a high (40A) pass through power capability which, unlike most other hybrid inverters, enables the Redback system to handle higher loads in both on and off-grid modes. The system functions much like a UPS with instantaneous backup and is able to operate in off-grid mode indefinitely (with adequate solar). The Redback system also includes inbuilt smart controls (relays) to turn on loads or appliances based on various settings. One of the clever cloud-based features is the remote access to configuration/settings which makes life easier for installers and customers alike. The only downfall is that most systems need to be hardwired to a modem as the wifi has proven to be unreliable in certain locations.

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Battery storage is integrated into the sleek weather rated cabinet and can house up to 4 of the well proven PylonTech LFP battery modules enabling up to 11.4kWh of total storage capacity (9.2kWh usable capacity at 80% DOD). The PylonTech LFP batteries are some of the best performing batteries in the ongoing tests conducted at the independent ITP renewables battery test centre.

Runners up - BESS systems

There are several other very good all-in-one BESS systems including brand new the Soltaro AIO2 system, the well-known AlphaESS Smile or Storion series, and we should mention the Senec V3 hybrid.

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