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Find reviews of the best Solar Products, SMA Sunny Boy, Aurora Power-One, Growatt, SunPower, SolaX, QCells, Trina Solar, Jinko, Selectronic, Tesla Powerwall, ABB, SMA Sunny Island, Hybrid inverters, battery sizing, Lithium-ion, lead-acid batteries, off-grid, on-grid, stand-alone power systems

4. Battery systems - Energy storage

Jason Svarc

solar battery home energy storage reviews

Most modern battery systems used for solar installations use lithium battery modules housed in a enclosure. Previously sealed lead-acid (Gel or AGM) batteries were used however this review will focus on the newer lithium batteries, plus the unique Sodium and Flow batteries now available. Up until very recently all batteries were DC only but in the last year 'AC batteries' have become available which is a little misleading as a AC battery is simply a DC battery with an integrated DC-AC inverter.

Most modern batteries are housed within a battery enclosure containing many sensors and a dedicated battery management system (BMS). The BMS is essential to monitor battery voltage, state of charge and cell temperature (thermal monitoring). Most of these DC battery systems require an additional solar hybrid or Interactive Inverter to complete the energy storage system.

Battery Evolution - A good example of the rapid changes happening in the battery world is highlighted in the evolution of the Tesla Powerwall. The first generation 6.4kWh Powerwall shown below is a high voltage in-string DC coupled battery which is installed together with a compatible solar hybrid inverter to function. However the second generation Powerwall 2 (AC version) which is due to be released in late 2017 will be an AC battery at double the capacity for close to the same price. Another example is the LG chem RESU range of batteries which has gone from a single battery unit to 8 different battery sizes and two voltage options in just over 1 year of development.

See the battery and energy storage summary table here

LG Chem RESU (LV)

LG Chem Ltd often referred to as LG Chemical is headquartered in Seoul, South Korea and was the 13th largest chemical company in the world by sales in 2014. LG Chem completed development and began mass production of Korea’s first lithium-ion batteries back in 1999.  LG Chem is the world’s third-largest maker with an annual production capacity of 1,000 million cells and is also a supplier of automotive battery for electric vehicles such as the Chevrolet Volt and Ford Focus electric.

See the full LG Chem battery review article here

Basic specifications: (3 battery sizes available)

  • Type: Battery system - Lithium NMC - ELV 48V battery
  • Use: Self-use, back-up, Off-grid (when used with an appropriate inverter)
  • Power output: 4.0kW (4.2kW peak) for 6.5kWh module
  • Battery System Voltage: 48V (51.8V)
  • Battery type: Lithium NMC (lithium-nickel-manganese-cobalt)
  • Battery size - 48V:  3.3kWh, 6.5kWh, 9.8kWh
  • Usable capacity: 90%

Features:

  • Compact, lightweight battery module with integrated BMS.
  • High surge/peak power output.
  • Expandable with up to 19.6kWh (with LG adapter)
  • Claimed 3000 cycles at 80% DOD (to EOL 70% capacity)

Note:

  • No DC to AC inverter included.
  • Large range of compatible hybrid inverters: Goodwe, Redback, Selectronic, SMA Sunny island, Schneider, Solax X hybrid, Victron Energy
  • Derates output in high ambient temperatures above 40 degC.
  • Warranty - 10 years

Price – LV 6.5kWh = AU$4600 ($710 per kWh)

 

LG Chem RESU (HV - 400V)

LG Chem RESU HV.jpg

LG Chem Ltd often referred to as LG Chemical is headquartered in Seoul, South Korea and was the 13th largest chemical company in the world by sales in 2014. LG Chem completed development and began mass production of Korea’s first lithium-ion batteries back in 1999.  LG Chem is the world’s third-largest maker with an annual production capacity of 1,000 million cells and is also a supplier of automotive battery for electric vehicles such as the Chevrolet Volt and Ford Focus electric.

See the full LG Chem battery review article here

Basic specifications: (2 battery sizes available)

  • Type: Battery system - Lithium NMC High Voltage DC battery
  • Use: Self-use, back-up (UPS)
  • Power output: 3.5kW, 5.0kW for 10kWh module
  • Battery System Voltage:  350-550V DC (400V nominal)
  • Battery type: Lithium NMC (lithium-nickel-manganese-cobalt)
  • Battery size -  7.0kWh and 9.8kWh total capacity
  • Usable capacity: 90% - 6.6kWh and 9.3kWh

Features:

  • Compact, lightweight battery module with integrated BMS.
  • High surge/peak power output.
  • Low voltage 48V and High Voltage 400V options
  • Claimed 3000 cycles at 80% DOD (to EOL 70% capacity)

Note:

  • No DC to AC inverter included.
  • Range of compatible hybrid inverters: SMA Sunny boy storage, SolarEdge StorEdge hybrid.
  • Warranty - 10 years

Price – HV 7kWh = AU$5600 ($760 per kWh)

 

Tesla Powerwall 2

Tesla Powerwall 2 comparison review

Tesla is an innovative company based California, USA specialising in electric vehicles such as the model S and advanced lithium battery technology. Headed by the well known entrepreneur Elon Musk, Tesla is now known as a world leader in energy storage tehnology and is constructing the worlds largest battery manufacturing facility known as the Gigafactory which is predicted to reduce the cost of lithium-ion storage batteries by up to 30% once fully operational in 2018.

Basic specifications: (1 battery size available)

  • Type: AC Battery system - Lithium NMC
  • Use: Self-use, back-up (UPS)
  • Power output: 5kW (7kW peak)
  • Battery System Voltage: 350-450V DC
  • Battery type & size: Lithium - NMC (nickel-manganese-cobalt) 13.2kWh
  • Usable capacity: 90% - 13.5kWh of total 15kWh capacity (estimated)

Features:

  • Integrated AC-DC converter.
  • Only outdoor weather rated (IP66) battery on the market.
  • Liquid thermal cooling.

Note:

  • DC model no longer available
  • AC model due for release April 2017
  • Up to 9 additional units to be connected in parallel
  • Warranty - 10 years

Price – AU$8500 ($590 per kWh)

 

Pylon Technology Extra 2000

 

Pylontech battery review

Shanghai Pylon Technologies Co., Ltd. is the leading chinese supplier and manufacturer of Lithium LiFePO Cell batteries. Producing a huge range of battery systems including High Energy LiFePO Cells, Telecom Backup Lithium Battery, Lithium UPS Battery, Car Starter Battery and Electric Vehicle Lithium Batteries.

Basic specifications: (1 battery size available)

  • Type: Battery system - Lithium LFP
  • Use: Self-use, back-up (UPS)
  • Power output: 2kW (2.2kW peak)
  • Battery System Voltage: 48V
  • Battery type & size: Lithium Iron Phosphate (LiFePO4)- 2.4kWh
  • Usable capacity: 80% - 1.92kWh

Features:

  • Compact battery module with integrated charger & BMS.
  • High surge/peak power output.
  • Expandable with up to 4 x 2.4kWh units
  • Claimed 4000 cycles at 60% DOD (to EOL 80% capacity)
  • Compatible with Redback, SolaX and many well known Inverters

Note:

  • No DC to AC inverter included.
  • Low surge/peak power output.
  • Compatible hybrid inverters: Goodwe, Redback, SMA Sunny island, Solax X hybrid
  • Warranty - 5 years

Price – AU$1600 ($660 per kWh)

 

GCL E-KwBe 5.6

GCL E-KwBe battery review

GCL (Golden Concord Holdings Limited) based in Hong Kong is an huge international company which is recognised as the world’s largest provider of solar cells. The E-KwBe is the first battery released under the subsidiary GCL system integration technology Co.

Basic specifications: (2 battery sizes available)

  • Type: Battery system - Lithium NMC
  • Use: Self-use, Off-grid (when used with an appropriate inverter)
  • Power output: 3kW (continuous & peak)
  • Battery System Voltage: 48V
  • Battery type & size: Lithium NMC (nickel-manganese-cobalt) - 2.5kWh & 5.6kWh sizes
  • Usable capacity: 90%

Features:

  • Attractive battery module with integrated charger.
  • Expandable (TBA)
  • Compatible with Goodwe SE hybrid inverters

Note:

  • No DC to AC inverter included.
  • Relatively low cycle life (2000 cycles)
  • Two sizes available - 2.5kWh & 5.6kWh
  • Warranty - 5 years

*Price –  AU$3700 ($660 per kWh)

 

BYD B-Box

BYD B-Box battery review

BYD Co is a leading Chinease vehicle and lithium battery manufacturer which began operations in 1995. Initially focusing on electric vehicles and mobile phone batteries BYD has recently entered the competitive home energy storage market.

Basic specifications: 

  • Type: Battery system: Lithium LFP - DC battery system
  • Size - Capacity: 2.5kWh modular (up to 10kWh), 12.8kWh
  • Use: Self-use, Off-grid (when used with an appropriate inverter)
  • Power output: 2.5kW per module (continuous & peak)
  • Battery System Voltage: 48V
  • Battery type: Lithium LFP (Lithium Iron Phosphate)
  • Usable capacity: 95% - 2.4kWh per module

Features:

  • Modular battery system with 2.5kWh units.
  • Compatible with common hyrbid battery 48V inverters
  • Compatible with many hybrid inverters including: SMA, Goodwe, Solax, Victron.
  • Can have up to 8 units in parallel
  • Warranty 10 years

Note:

  • No DC to AC inverter included.
  • Must be installed indoors (IP20 rated)

Price bracket – TBA

 

BYD B-Box HV

BYD B-Box battery review

BYD Co is a leading Chinease vehicle and lithium battery manufacturer which began operations in 1995. Initially focusing on electric vehicles and mobile phone batteries BYD has recently entered the competitive home energy storage market.

Basic specifications: 

  • Type: Battery system: Lithium LFP - HV DC battery system
  • Size - Capacity: 1.12kWh modular (up to 10kWh)
  • Use: Self-use, Backup (UPS)
  • Power output: 1.1kW per module (continuous), Peak = 2kW
  • Battery System Voltage: 200-500V DC
  • Battery type: Lithium LFP (Lithium Iron Phosphate)
  • Usable capacity: 95% - 1.05kWh per module (9.5kWh for 9 modules)

Features:

  • Modular battery system with 1.12kWh units.
  • Compatible with HV hybrid inverters including: SMA Sunny boy storage, SolarEdge StorEdge hybrid.
  • Can have up to 5 systems in parallel
  • Warranty 10 years

Note:

  • No DC to AC inverter included.
  • To be installed in protected location (IP55 rated)

Price bracket – TBA

 

Simpliphi PHI

Simpliphi PHI battery review

Simpliphi previously known as LibertyPak is US based battery manufacturer which has been a leading developer of Lithium based batteries since 2002. Initially developed for durable remote and mobile power systems the Simpliphi batteries are known for their high cycle life, safety and stability.

Basic specifications: (2 battery sizes available)

  • Type: Battery system - Lithium LFP
  • Size - Capacity: 2.6, 3.4kWh modular (up to 10kWh), 12.8kWh
  • Use: Self-use, Off-grid (when used with an appropriate inverter)
  • Power output: 2.9kW per module (continuous & peak)
  • Battery System Voltage: 24V, 48V
  • Battery type: Lithium LFP (Lithium Iron Phosphate)
  • Usable capacity: 100%

Features:

  • Modular battery system up to MWh scale
  • Compatible with common hyrbid battery (24V or 48V) inverters
  • Very high cycle life (10,000+ claimed)
  • Safe, stable battery chemistry

Note:

  • No DC to AC inverter included.
  • Must be installed indoors (IP20 rated)
  • Warranty - 10 years

Price bracket – TBA

 

SolarWattMyReserve

SolarWatt MyReserve battery.jpg

SOLARWATT GmbH based in Germany was a well known solar panel manufacturer but restructured in 2012 to focus on energy solutions including battery storage systems. SolarWatt also created a partnership with BMW i to deliver high efficiency, large scale solar PV solutions.

Basic specifications: (1 size available)

  • Type: DC in-string battery system - Lithium-ion
  • Use: Self-use
  • Power output: 4kW (continuous & peak)
  • Battery System Voltage: 48V
  • Battery type & size: Lithium-ion - 2.2kWh (expandable up to 11kWh)
  • Usable capacity: 90% - 2kWh

Features:

  • Modular battery system with integrated inverter/charger.
  • High efficiency - 96.7% claimed
  • Expandable up to 11kWh
  • DC in-string system for easy add-on to existing systems
  • Compatible with most solar inverters (claimed)

Note:

  • Cycle life unknown
  • No back-up capability
  • Warranty - up to 10 years

*Price –  $- TBA

 

Solax Battery

Solax battery review.jpg

Suntellite Group headquarters is located in Zhejiang University with two major manufacturing plants in China, 14 laboratories and five engineering research and technology centers throughout China. Solax Power a subsidiary of the Suntellite Group manufacturers solar cells, panels, inverters, solar racking and LED lighting technology. Solax teamed up with LG chem to create the solax battery.

Basic specifications: 

  • Type: Battery system - Lithium NMC
  • Size - Capacity: 3.3kWh, 6.5kWh (parallel up to 10 units)
  • Use: Self-use, back-up
  • Power output: 3.0kW per module (continuous & peak)
  • Battery System Voltage: 48V
  • Battery type: Lithium NMC (Nickel-Manganese-Cobalt)
  • Usable capacity: 95% claimed

Features:

  • Modular battery system with 3.3 or 6.5kWh (up to 10 units)
  • Compatible with common hyrbid battery 48V inverters
  • Optional forced air cooling
  • 10 year warranty
  • Uses LG chem lithium NMC cells

Note:

  • No DC to AC inverter included.
  • Must be installed indoors (IP21 rated)

Price bracket – TBA

 

Ecoult Ultrabattery

Ecoult Ultrabattery review.jpg

Ecoult was formed in 2007 by the leading Australian scientific research organisation (CSIRO), but was acquired by the United States-based East Penn Manufacturing Company in 2010. The Ultrabattery is based on a unique long-life lead acid/ carbon capacitor technology and is lead based so is easily recyclable and environmentally sound. Ideal for larger commerical energy storage systems wih high demand plus well suited for remote microgrids.

Basic specifications: (Modular battery system)

  • Type: Battery system - Unique lead-acid capacitor combination
  • Use: Self-use, Off-grid, back-up
  • Power output: up to 20kW peak
  • Battery System Voltage: 48V
  • Battery type & size: Ultrabattery - 16.9kWh usable
  • Usable capacity: 90% - 25.4kWh

Features:

  • Unique lead-acid battery with carbon ultra capacitor
  • Very high power output -up to 20kW
  • Very good rapid charge and discharge
  • Individual battery unit monitoring
  • 90% Depth of Discharge available for backup
  • Stackable up to MWh storage capacities
  • Safe, fire retartant system
  • Good temperature tolerance

Note:

  • No DC to AC inverter included.
  • High energy to weight ratio -up to 1,100 kg
  • More suited to larger commerical applications
  • Warranty - 10 years

Price bracket – $16500 = $1,650 per kWh

 

Aquion EnergyAHI Battery

 

Aquion battery review

Aquion Energy is headquartered in Pittsburgh, with a manufacturing facility in Westmoreland, Pennsylvania. Aquion’s Aqueous Hybrid Ion (AHI™) battery systems are optimized for stationary, long duration daily cycling applications, including off-grid and microgrids, energy management, and grid-scale energy storage applications. The batteries utilize non-corrosive reactions at the anode and cathode to prevent deterioration of the materials. The water-based chemistry results in a nontoxic and non-combustible product that is safe to handle and environmentally friendly.

Basic specifications: (Modular battery system)

  • Type: Battery system - Sodium-ion
  • Use: Self-use (UPS when used with an appropriate inverter)
  • Power output: 8.1kW (9.7kW peak) - M100 series module
  • Battery System Voltage: 48V
  • Battery type & size: Each Individual S20 stack is 2.4kWh (The M100 module is made up of 12 x S20 stacks for total 25kWh)
  • Usable capacity: 100% - 2.4kWh (only over low 24hr discharge rate)

Features:

  • Battery module with integrated protection
  • 100% Depth of Discharge available
  • Stackable up to MWh storage capacities
  • Non-toxic materials

Note:

  • No DC to AC inverter included.
  • High energy to weight ratio - 113kg per stack
  • Requires inverters with programmable charge voltage parameters which can operate in wide voltage window (40-60V)
  • May require additional battery management system to operate.

Price bracket – TBA

Redflow Zcell (ZBM2)

 

Redflow Zcell battery

Redflow, now an International company started in Australia has a new manufacturing facility (relocated) in China. The Zcell was one of the worlds first domestic flow battery systems (based on the previous version Redflow ZBM2 battery). The unique zinc bromide flow battery technology developed by the University of Queensland is capable of 100% discharge and can withstand partial or no charge for prolonged periods of time without degradation.

Basic specifications: (Modular battery system)

  • Type: Battery system - Zinc Bromide
  • Use: Self-use, Off-grid when used with an appropriate inverter
  • Power output: 3.0kW (5.0kW peak)
  • Battery System Voltage: 48V
  • Battery type & size: Zinc Bromide flow battery - 10kWh
  • Usable capacity: 100% - 10kWh

Features:

  • Unique flow battery system with integrated protection
  • 100% Depth of Discharge available
  • Stackable up to MWh storage capacities
  • Safe, fire retartant system
  • High temperature tolerance

Note:

  • No DC to AC inverter included.
  • High energy to weight ratio - 240kg per unit
  • DC-DC conversion efficiency of 80%
  • Requires inverter with programmable charge voltage parameters which can operate in wide voltage window (40-60V)
  • Warranty - 10 years

Price bracket – $12500 = $1,250 per kWh

 

Enphase AC Battery

 

Enphase AC battery

Enphase Energy is a Californian company founded in 2008. Enphase is considered the world's leading manufacturer of solar micro-inverters and is well established in the US market. The recent release of the compact AC battery in mid 2016 is one of the first modular AC battery systems available.

Basic specifications: (Modular AC battery system)

  • Type: AC Battery system - Lithium-ion
  • Use: Solar self-use and off-peak charging only
  • Power output: 0.26kW per module
  • Battery System Voltage: N/A (AC battery)
  • Battery type & size: Lithium (LiFePO4) - 1.2kWh
  • Usable capacity: 95% - 1.14kWh

Features:

  • Attractive, compact, modular AC-battery
  • Integrated AC inverter
  • Can operate as a stand-alone unit (not back-up)
  • Stackable up to 13 units (15.6kWh)
  • Sophiticated monitoring system (with additional Envoy)
  • Very high cycle life (claimed 7,300 at 80% DOD)

Note:

  • No back-up power capability
  • Additional Enphase Envoy S unit required for setup and monitoring
  • Low power output per module - 260W
  • Low weather rating (IP20) must be installed indoors
  • Warranty - 10 years

Price bracket – $1850 = $1540 per kWh

 

Sonnen Sonnenbatterie ECO

 

Sonnen ECO battery review

Sonnen is successful German company founded in 2010. Previously known as Sonnenbatterie, Sonnon has become a leader in developing high quality, modular energy storage systems for residential and commercial applications.

Basic specifications: (Modular AC battery system)

  • Type: AC Battery system - Lithium LFP
  • Use: Solar self-use and emergency back-up power
  • Power output: 3.0kW (8.0kW peak)
  • Battery System Voltage: N/A (AC battery)
  • Battery type & size: Lithium LFP (LiFePO4) - 4kWh to 16kWh (2kWh modules)
  • Usable capacity: 100% (assumed capacity is 2.2kWh)

Features:

  • Attractive, modular system
  • Can operate as a stand-alone unit with some back-up support
  • Stackable up to 16kWh
  • Sophiticated monitoring system
  • Very high cycle life (claimed 10,000 cycles)

Note:

  • Relatively low inverter power output 3.0kW
  • Low weather rating (IP20) must be installed indoors
  • Back-up functionality limited
  • Warranty - 10 years

Price bracket – Approx AU$1250 per kWh