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 Due to the rapid improvements in lithium technology, modern lithium battery systems quickly superseded traditional lead-acid batteries as manufacturers developed smart, modular systems to suit different energy storage applications.

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

Battery sizing

Unfortunately, the one-size-fits-all approach is often taken when it comes to sizing a battery which can lead to poor performance and not meeting the consumer’s expectations. This is typically due to two main reasons:

• Undersized batteries – do not have enough capacity to meet the household demand.
• Oversized batteries – 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 and sized by a qualified designer according to a number of important factors including; solar array size (existing or new), system type (on-grid or off-grid), backup power requirements, and most importantly, the evening or overnight energy consumption (kWh). Fortunately, most modern battery systems are modular and scalable so they can be sized accordingly. With this in mind, we selected the best batteries according to the six following categories:

Best Solar Battery Systems

No#	Image	Make & Model	Battery Category	Total Capacity (kWh)	Cost per kWh (AU$)
1		Goodwe Lynx U-Series	Best small battery up to 5kWh	5.4kWh (max 6 modules)	$610 *
2		BYD LVS & LVL	Best Low-voltage modular battery system	4kWh to 256kWh	$750 *
3		Huawei LUNA2000	Best High-voltage modular battery system	5kWh to 30kWh	$760 *
4		Tesla Powerwall	Best AC-coupled battery system (retrofit)	13.5kWh (max 3 modules)	$815 ^
5		PowerPlus Life Premium	Best off-grid battery system (stand-alone)	3.3kWh to 500kWh	$970 *
6		Redback Smart Hybrid	Best all-in-one solar battery system (BESS)	4.8kWh to 11.4kWh	$920 ^^

Table notes: (*) price does not include an inverter. (^) includes an inbuilt battery inverter. (^^) includes an inbuilt battery and solar inverter.

Battery Capacity – kWh

Battery size or capacity is measured in kWh (kilowatt-hours). This is the total amount of energy a battery can store. However, the usable capacity may differ from the total battery capacity. Generally, the usable capacity is limited to 80 to 90% of the total battery capacity to increase the lifespan and avoid a potential battery shutdown event at very low charge levels. For example, a lithium battery with 10kWh total capacity may have its usable capacity limited to 80% to increase lifespan. Therefore, 8kWh of energy can be discharged on a daily basis. However, often the remaining 10 to 20% is available in emergencies, such as a prolonged blackout depending on how the system is programmed.

The simple solar and battery sizing calculator tool can help you quickly and easily calculate the optimum size solar and battery system for your home or business.

Battery life and degradation

Home energy storage battery systems have only been widely available for around eight years so real-world performance and degradation data is still incomplete. However, our data gathered so far through testing and monitoring of various (lithium) home battery systems suggests an 8 to 15+ year lifespan. The life of a battery is generally determined by either the number of charge and discharge cycles, or total energy throughput (kWh). All batteries lose capacity over time with the end-of-life generally after a lithium battery has lost around 30% of its original capacity, this generally occurs after 10 years, based on one full charge cycle per day. However, lithium battery cell technology is constantly advancing and some batteries, such as the Lithium Titanate (LTO) variety from Zenaji, can last well over 20 years.

ITP Renewables based in Canberra Australia has been conducting battery performance tests since 2016. The accelerated testing program is performed in a variable climate-controlled lab to simulate real-world conditions and has produced some very interesting results. Lithium cell degradation is dependent on a number of factors including temperature, depth of discharge, and rate of charge. Based on the currently available data from ITP, battery end-of-life is estimated to be 3000 to 4000 cycles or 9 to 12 years. See our detailed Home Battery Storage Guide for a more detailed explanation.

Different types of lithium batteries

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 inverter. For example, high-voltage or HV batteries can only be used with an 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 designed to work with powerful off-grid inverter-chargers.

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 ratings – Continous and peak
• Efficiency – charge & discharge losses
• Cost – Battery upfront cost
• Cycle life – capacity loss over time
• Inverter and system compatibility
• Operating temperature range
• Manufacturers warranty conditions

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

Battery cost comparison

Battery prices can vary significantly depending on the country and exchange rate and not all the batteries listed here are available in every region. Australia is one of the world leaders in home battery installations and has access to a huge variety of batteries from Asia and Europe, therefore the following batteries are compared based on the cost per kWh in Australian dollars (AU). Conversion to US dollars is AU$1.0 = US$0.74. The prices do not include installation or any additional electrical modifications that may be required. A compatible hybrid (battery) inverter is not included in the price for the DC-coupled battery systems listed. The AC-coupled and all-in-one battery categories include an inbuilt inverter.

For a detailed comparison of the upfront cost and operational cost of various lithium home batteries, see our detailed analysis of the leading lithium battery systems including many of the batteries in this review – See the detailed home battery storage review.

Best small battery up to 5kWh

1. Goodwe Lynx U-Series

Goodwe was founded in 2010 and has earned a reputation as one of the top Chinese solar inverter manufacturers. The company was a pioneer in hybrid battery storage technology and has engineered a vast range of residential, commercial, and utility-scale inverters and numerous energy storage systems. GoodWe’s new Lynx Home U Series battery is a feature-packed, cost-effective battery system built using safe and proven lithium iron phosphate (LFP) cells. Each low-voltage (48V) Lynx battery has a total capacity of 5.4kWh with 90% usable or 4.8kWh. For additional storage requirements, up to six Lynx batteries can be connected in parallel to provide up to 28.8kWh of usable storage capacity.

Goodwe Battery specifications

• Type: DC battery system – Lithium LFP cells
• Size: 5.4kWh with 90% usable capacity
• Power output: 2.5kW continuous, 2.9kW max peak – Power increases to 5.76kW with 2 or more batteries in parallel.
• Cycle life: up to 4000 cycles (claimed)
• Price: $3300 (US$2600)
• Warranty: 10 years to 70% minimum retained capacity.
• Compatibility: Goodwe Hybrid inverters: ES, EM, BP, SBP series

Download the full Lynx U series battery specifications datasheet.

The Lynx battery system boasts a range of innovative features, including remote monitoring and software upgrades, plus the ability to identify additional parallel modules automatically, making setup effortless. More importantly, the Lynx battery can automatically reboot after entering self-protection mode due to an under-voltage event; this is a common problem on many batteries during a prolonged blackout when the battery is drained to very a low state of charge. In order to wake up and start charging after a low voltage event, many other managed lithium battery systems (using the standard CAN bus communications) need to be manually restarted via a specific startup procedure which can be problematic for an untrained user. Fortunately, this will not be an issue with the Goodwe Lynx batteries when coupled with a compatible Goodwe hybrid inverter.

While output power is limited to 2.5kW continuous using one battery, the power rating is increased to 5.76kW with two or more batteries in parallel. Generally, 2.5kW is adequate for a battery of this size and will cover most average household loads. More importantly, the conservative power rating helps increase battery life by limiting the internal heating of the cells during use. Learn more in our detailed Goodwe Inverter and battery review.

Best low-voltage modular battery system

2. BYD Premium LVS & LVL

BYD is a huge Chinese battery manufacturer that recently launched into the global electric vehicle and energy storage markets. The company was first established way back in 1995 and offers a wide variety of Lithium battery systems based on LFP or lithium iron 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, and now boasts a range of modular stackable battery systems for high and low-voltage (48V) systems.

BYD LVS & LVL Battery specifications

• Type: DC battery system – Lithium LFP prismatic cells
• Size: LVS: 4.0kWh (100%) usable – expandable to 256kWh
• Size: LVL: 15.3kWh (100%) usable – expandable to 983kWh
• Power output: HVS = 3.3kW per module, Max Peak 4.6kW (5 sec)
• Power output: LVL = 12.8kW, Max Peak 19.2kW (5 sec)
• Cycle life: up to 8000 cycles (claimed) – Ref warranty doc
• Price: LVS = $750 per kWh (US$555)
• Price: LVL = $684 per kWh (US$500)
• Warranty: 10 years to 60% minimum retained capacity.
• Compatibility: SMA, Selectronic, Victron, Sungrow, Goodwe, Solis.

The LVS Premium series is a 48V modular tower battery system designed to cater for different energy storage requirements. The LV tower system uses a battery monitoring unit (BMU) to manage and control each individual 4.0kWh module. Usable capacity is 100%, and up to 6 modules can be installed per tower for a total of 24kWh. For greater storage capacity, multiple towers of 4 modules can be linked together with a maximum of 16 towers, or 256kWh. Note, while the usable capacity is listed at 100%, the real-world capacity will be lower due to common inverter voltage limitations and inbuilt protection to prevent black-start events which often occur when the battery is drained below 10% state of charge.

The BYD Premium LVL series has a much larger 15.4kWh capacity and is designed for larger off-grid, grid-tie and even off-grid energy storage applications. While not technically stackable, it is modular and scalable up to an impressive 983kWh, close to 1.0GWh.

Learn more in the detailed BYD battery review

Best high-voltage modular battery system

3. Huawei LUNA2000

Huawei is not only a leader in communication and mobile technology but has become a leading innovator when it comes to solar energy storage technology. Building on decades of experience in large scale commercial and utility solar, Huawei moved into the residential solar market in 2018 with an efficient, lightweight hybrid solar inverter that offered an impressive range of features at a very competitive price. More recently, Huawei released the LUNA2000 modular residential battery system with an equally impressive range of features and new innovations as explained below.

LUNA2000 Battery specifications

• Type: DC battery system – HV battery modules
• Size: 5.0kWh with 100% usable capacity
• Power output: 2.5kW continuous, 3.5kW max peak per module
• Cycle life: up to 4000 cycles (claimed)
• Price: $3800 (5kWh) = $760 per kWh (US$580)
• Warranty: 10 years to 60% minimum retained capacity.
• Compatibility: Huawei SUN2000 inverters – single-phase & 3-phase

The 5kWh LUNA2000 battery modules are built using lithium iron phosphate (LFP) cells and can be stacked three high for a maximum of 15kWh. However, the system can be expanded with a second stack offering up to 30kWh of total capacity with two stacks in parallel. Lithium Iron Phosphate (LFP) is widely known as one of the safest and most stable battery chemistries.

Unlike most other high-voltage battery systems, which are connected in series to increase the system voltage, the Huawei modules are connected in parallel as each module operates at 350V to 430V. This improves overall efficiency as each module is closer to the inverter optimum operating voltage and the current is reduced, resulting in lower cable and conversion losses. The LUNA2000 system also features several clever innovations, including a thermal management system that can pre-heat the cells in extremely low temperatures and an AI system that can detect short circuits or damage.

LUNA2000 battery unique innovations and features:

• AI-powered internal cell short circuit diagnosis to avoid fire hazards
• Module-level battery optimisers support new and old batteries in one system.
• Internal heating system for better performance in extremely cold climates

Learn more in our detailed Huawei inverter and Luna2000 battery review

Best AC coupled battery system

4. Tesla Powerwall 2

The first Tesla Powerwall is 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 $10,500, but considering the considerable 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 solar. Furthermore, to enable backup power in the event of a blackout, the 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: $11,000 + backup gateway = $815 per kWh (US$600)
• Warranty: 10 years to 70% minimum retained capacity.
• Compatibility: Any solar inverter (AC coupled)

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 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. Learn more in the detailed Tesla Powerwall 2 review.

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.

Best off-grid battery system

5. PowerPlus Energy LiFe Premium

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 the many common managed** lithium battery systems on the market from manufacturers such as BYD and LG, self-managed lithium battery systems do not require a communication connection (CAN bus) with the inverter and are compatible with almost all leading off-grid inverter-chargers. These batteries can also be used as a drop-in replacement for older lead-acid battery banks and generally do not shut down after a low-voltage or low SOC event. We should also note, in certain situations, self-managed battery modules can be ‘hot-swapped’ or replaced without shutting the down site if there is an issue.

** Some managed lithium battery options that rely on communications (CAN bus) can be problematic, especially at a 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 $3,400 = $970 per kWh (US$710)
• Warranty: 10 years to 70% minimum retained capacity.
• Compatibility: Most 24V, 48V, or 120V off-grid or hybrid inverters

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. Powerplus Energy also offers a more affordable ECO 4kWh battery option.

Other reliable off-grid battery options

Due to limited supply, not all countries have access to Powerplus Energy batteries, however, there are several other trusted high-performance, self-managed lithium batteries available. In North America, the Simpliphi PHI and Discover AES batteries are very well regarded, while GenZ and the unique long-life Zenaji Aeon lithium titanate batteries are other options available in Asia and Australia.

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

Best all-in-one system – BESS

6. Redback Tech Smart Hybrid

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 = $920 per kWh (US$675)
• Warranty: 10 years to 60% minimum retained capacity.
• 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. The Redback system is now also available in a larger more powerful 3-phase configuration for 3-phase homes and businesses.

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 the new Soltaro AIO2 system and the AlphaESS Smile or Storion series. We should also mention the German-made Senec V3 hybrid system which is a very popular choice in Europe.

Author:Jason Svarc