Tesla Powerwall 2:
With the release of the first-generation Powerwall almost 7 years ago Tesla Energy made a big impact in the solar world and pushed home energy storage into the mainstream. Released in 2016, the current Powerwall 2has been designed to be more compact, easier to handle, and simpler to install than the first Powerwall.
Features:
- AC-Coupled Battery System with Lithium-Ion Battery Pack
- 13.5kWh Storage Capacity
- 10-year Warranty
- Automatic, Virtual System Updates
- Child & Pet Friendly, with No Wires or Hot Vents
- Quiet Operation
- Can be Retrofitted to Your Existing Solar System
- Easily Stackable for System Flexibility
Powerwall 2 comes with rectangular curves, venting on either side for cooling, a bright green LED strip, a simple on/off switch IP56 rating and can be ground-mounted and wall-mounted. The Powerwall 2 uses Lithium NMC (Nickel-Manganese-Cobalt) Battery Cells similar to the Lithium NCA cells used in the Tesla electric vehicles, which are developed by Tesla in collaboration withPanasonic.
Tesla Powerwall 2 hasan integrated AC to DC inverter-charger; hence, it can be easily retrofitted to homes with an existing solar installation. To function together with a solar array, the Powerwall system requires a separate solar inverter. However, it is compatible with ‘almost’ any model of inverter since it operates independently of the Powerwall.
Management System:
Tesla Powerwall 2 is equipped with a Liquid Thermal Management System that enables it to operate in a wide range of temperatures from -20 to +50°C and is still the only battery in the market with that technology. The Powerwall is likely to derate or reduce its power output at ambient temperatures above 40°C, as power derating is very common among most lithium-ion-based batteries. However, theliquid thermal management system helps it by expelling more heat under high loads and during rapid charging, which can provide a longer life span and better performance at higher temperatures. Another advantage of that system is that it enables the Powerwall to charge at temperaturesbelow freezing becausewhen the temperature is below freezing, preconditioning turns on and heats the Powerwall to improve charging performance. Whereas, many other lithium batteries suffer from severely reduced charge rates in such situations, as Lithium battery cells cannot charge properly below 5°C due to reduced diffusion rates on the anode.
Storage Capacity:
The Powerwall 2 comes with a large 13.5kWh storage capacity.For more storage capacity, it can be installed up to 3 modules per phase, which can provide an impressive 40.5kWh of total storage capacity per phase and more than enough for most standard households. Hence, on a 3-phase configuration, one can go up to nine units of Powerwall linked together.
Tesla Powerwall 2 isOff-Grid Capable provided it is installed in a protected location with an adequately sized solar array, plus a backup generator is required in most colder locations with short winter days. But for such a setup, more than one Powerwall is required as its charge rating is limited to a maximum of 5kW of solar (solar inverter size).
The Tesla App is easy to interface with and common to all Tesla products. It provides a seamless interface between EV control, solar generation and energy storage. It also offers real-time monitoring of grid energy usage, battery state of charge, solar generation historical data and useful statistics. It provides 4 different control modes.
- Self-Powered mode – Increases self-consumption of solar by storing excess generation.
- Time-based control – Prioritises energy storage or consumption based on your electricity usage tariffs to reduce bills and save money.
- Storm watch – Automatically charges the Powerwall in the event of a major storm or blackout.
- Vehicle charging during a power outage – Enables the Powerwall to Tesla EVA to dynamically adjust the charge rate to prevent overloading the system during a power outage.
LG RESU (LG Residential Storage Unit):
The maker of LG Chem Energy Storage System (ESS) is LG Chem Ltd., also often referred to as LG Chemical, a Korean company owned by LG Corporation. LG Chem manufactured Korea’s first lithium-ion batteries in 1999 and by the end of 2011, it had become the world’s third-largest manufacturer. LG is one of the most notable, well-known and respected ESS brands in the energy storage industry. It competes well with other ESS giants, including Tesla, BYD, Panasonic and Samsung.
In September 2020, LG Energy Solutions, the company under which LG makes its ESS, was spun off from LG Chem. It now accounts for more than 20% of the global electric vehicle battery market and supplies giants including Tesla, General Motors and Volkswagen. It also supplies batteries for drones and ships and battery-powered spacesuits to NASA.
Cell Chemistry
The LG RESU batteries are made from Lithium (nickel manganese cobalt oxide) NMC pouch cells. The NMC pouch cells are the choice cell technology used by many electric car manufacturers. They are safe and long-lasting. The unique Polymer ‘pouch’ flat laminated battery design (PH3) enables their batteries to have much higher energy density with increased reliability and safety. Designing the cell structure in this way reduces the likelihood of failure and enables an even distribution of heat across the cell area.
They incorporate a Battery Management System (BMS) that allows users to monitor the battery state information such as voltage, current and temperature and troubleshoot abnormal symptoms that lead to energy losses over time. They also have inbuilt sensors that monitor cell temperature and voltage and help extend battery life. Also, the LG BMS system lowers the power output by 50% once the internal cell temperature rises above 50°C and further lowers power output completely once the temperature goes above 55°C. In this way, it helps reduce degradation and the chance of thermal runaway.
95% Depth of discharge (DoD)
The DoD of a battery is the level that the battery can be discharged without damaging it. The RESU batteries allow up to 90% DoD except for the 16kWh variant which allows up to 100% DoD.
Compatibility With Industry-Standard Inverters
Unlike the Tesla which is limited to two inverter types, the RESU battery models are compatible with a wide range of industry-standard solar and hybrid inverters, including Huawei, Growatt and Victron, allowing buyers a wide range of options that they can integrate with their batteries.
Maintenance-Free
LG RESU batteries are maintenance-free meaning that they do not require any maintenance checks during their entire lifespan. Their design eliminates worries about constant maintenance and the attending costs and potential hazards.
Roundtrip Efficiency
A battery’s roundtrip efficiency is the measure of electrical losses involved with cycling the battery. The higher the roundtrip efficiency percentage, the more efficiently the battery can store and afterwards release the electricity it receives. The LG Chem RESU batteries have a roundtrip efficiency of 94.5%, one of the best in the market.
IP55 Rated
All LG RESU batteries have an Ingress Protection rating of 55. This means they can be installed in a semi-outdoor location such as a veranda or carport, though they are not to be exposed to direct sunlight.
Natural Cooling
They are designed to be cooled through the flow of natural airflow onto the slit-shaped frame of the batteries.
Warranty
LG Energy Solutions guarantees that their batteries will retain at least 60% of storage capacity for either 10 years after the date of the initial installation or for a Minimum Energy Throughput, (22.4MWh), whichever comes first. LG Chem will either fix, replace, or refund the cost of the battery if its capacity degrades faster than specified in the warranty terms. This matches the industry standard warranty offered by the leading brands.
LG Chem Product Line
The 48V Line (Low Voltage Series)
The 48V line includes the RESU3.3 (3.3kWh), RESU6.5 (6.5kWh), RESU10 (0kWh) and RESU13 (13kWh). The 48V line batteries are designed to be used in both hybrid and off-grid setups.
The 400V Line (High Voltage Series)
The 400V line includes the RESU7H (7kWh) and RESU10H (20H). They come in Type-R (Communication via RS485) and Type-C (Communication via CAN2.0B) options. The 400V batteries are designed for use in hybrid setups and cannot be used in off-grid applications.
The RESU Prime(High Voltage Series)
The LG RESU Prime are available in two sizes, the Resu 10H Prime with a capacity of 9.6 kWh and the Resu 16H Prime with a capacity of 16 kWh. They incorporate a converter that enables them to operate with high-voltage battery inverters.
BYD:
Founded in 1995, Build Your Dreams (BYD) is a pioneer in battery technology. The BYD company, based in Shenzhen China, is focused on four different industry sectors; Automotive, Rail Transit, Electronics and New Energy which encompasses solar and battery systems. BYD produces a variety of different lithium chemistries, however, the LFP or Lithium Ferro Phosphate, is the chemistry of choice for all stationary applications due to the increased safety and stability.
BYD’s new Battery-Box Premium range is available in three main variants; the high voltage HVS & HVM range, and two lower voltage 48V options, the LVS and the LVL Premium.
Battery-Box Premium HVS / HVM
The Battery-Box Premium HVS is BYD’s award-winning cobalt-free lithium iron phosphate (LFP) battery and consists of 2 to 5 HVS battery modules connected in series. This enables a usable capacity of 5.1 to 12.8 kWh to be achieved. If even more capacity is required, the direct parallel connection of up to 3 identical Battery-Box Premium HVS enables a maximum capacity of 38.4 kWh. Later scaling is possible by adding further HVS modules or parallel HVS towers. Thanks to the patented modular plug-in design, no internal cabling is required, which makes the high-voltage storage system particularly user-friendly. Thanks to its compatibility with leading 1-phase and 3-phase inverters, the battery storage system offers a high degree of flexibility, meets the highest safety standards and offers a long service life and high performance. The high discharge capacity, backup power and off-grid capability enable the system operator to make their home self-sufficient. This makes this home storage system the perfect option for anyone who wants to optimize their self-consumption and increase their self-sufficiency.
The Battery-Box Premium HVM is the big brother of the HVS storage system. A Battery-Box Premium HVM consists of 3 to 8 HVM 2.76 kWh battery modules, which are connected in series to achieve a usable capacity of 8.28 to 22,08 kWh. In addition, the direct parallel connection of up to 3 identical Battery-Box Premium HVM enables a maximum capacity of 66.24 kWh. As with the HVS, scalability is possible at any time by adding further HVM modules or parallel HVM towers. Apart from the capacity, the Battery-Box Premium HVM differs only slightly from the HVS.
Battery-Box Premium LVS
In contrast to the HVS/HVM, the Battery-Box Premium LVS is a low-voltage battery storage system. The main difference between the HVS/HVM and the LVS/LVL is the voltage level, which is lower for low-voltage batteries. A Battery-Box Premium LVS contains between 1 and 6 LVS battery modules stacked in parallel and can achieve a usable capacity of 4 to 24 kWh. At the same time, up to 16 Battery-Box LVS 16.0 can be connected in parallel to achieve a maximum total capacity of 256 kWh. After commissioning, the LVS can be flexibly scaled by adding further LVS modules or parallel towers.
Battery-Box Premium LVL (2021)
The BYD Battery-Box Premium LVL is a lithium iron phosphate (LFP) battery for use with an external inverter. The Battery-Box Premium LVL can be scaled to meet all project requirements, no matter how large they may be. Starting with a capacity of 15.36 kWh with the LVL15.4, the battery can be expanded to a maximum of 983 kWh by connecting up to 64 batteries in parallel (via a battery management unit). The LVL (2021) version is fully compatible with older LVL versions and brings additional benefits such as even easier installation, space savings by stacking 2 LVL 15.4, powerful emergency/backup power and off-grid functionality.
Sungrow:
Sungrow was founded in China in 1997 by Professor Cao Renxian from Hefei University of Technology, China. Sungrow solar inverters are highly reliable and backed by excellent tech support and warranties.Sungrow hybrid inverters when matched with the noteworthy Sungrow batteries are an excellent way to get home storage for thousands of dollars less than another costly brand.
Key Points of Sungrow Batteries:
HIGH-PERFORMANCE
- Up to 30A continuous charging and discharging current with high efficiency
- Up to 100% usable energy
SAFETY
- Lithium iron phosphate Battery
- Multi-stage protection design and extensive safety certification
FLEXIBILITY
- Extendable during lifetime
- Support 3-8 modules per unit, max. 4 units in parallel, 9–100 kWh capacity range
EASY INSTALLATION
- Compact and light, single-person installation
- Plug and play, no cables are needed between battery modules
Sungrow High-Voltage Modular Batteries are made using Lithium Ferro Phosphate (LFP) cells which are considered the safest and longest-lasting battery cell chemistry. They are compatible with Sungrow Single-Phase (SH-RS) and Three-Phase (SH-RT) hybrid inverter range. Each battery unit comprises a base unit, a head unit containing the Battery Management System (BMS), a slide-in switchgear DC isolator, and three to eight 3.2kWh lithium battery modules.
Each battery unit comprises a minimum of 3 modules of the battery (which means the minimum size of a battery is 9.6kWh) and a maximum of 8 modules per unit (which comes to 25.6kWh). However, it can go up to 100kWh with 4 stacks of 8 modules in parallel. It is easily scalable and up to 100% usage of the stored energy. It offers high charge and discharge efficiency, minimizing energy losses during the storage and retrieval of power. It comes with 10 years of warranty.
Its Battery Management System (BMS) monitors the battery against overcharging, over-discharging, short circuits, and overheating. That helps in extending the battery’s lifespan, improves safety, and provides real-time monitoring and control.
Alpha-ESS:
Alpha-ESS is a Chinese manufacturer based in Jiangsu, China, and makes its batteries in Suzhou, China. It was founded in 2012 and has 10+ subsidiaries providing local services and 40000+ systems actively running in over 50 countries, including Germany, Australia, Italy, South Korea and the United Kingdom.
According to a 2021 report, Alpha-ESS accounted for 15% of the global market share of the 4.5GWh of residential solar batteries shipped in 2020, next to Tesla and Pylontech. Alpha-ESS has won multiple awards for its products and has a strong reputation in the ESS market as a leading brand. It has also expanded its production lines to include portable solar generators, the commercial & industrial, with all of its products subjected to multiple international standard certificates including IEC, TÜV Rhine, KBIA, and JET.
Battery Cell:
Alpha-ESS makes its batteries with the Lithium Iron Phosphate Cells. This makes them safe, long-lasting and able to operate under high temperatures without the risk of explosion.
Installation:
Alpha-ESS offers Modular Energy Storage Systems. They are compatible with both new installations (DC-coupled) and retrofits (AC-coupled), and they can be installed off-grid too. The incorporated inverter eliminates the additional cost of an inverter. For those houses with an existing Solar PV System, they can be AC-coupled to the system.
Design:
They are designed with aesthetically pleasing storage units in which individually purchased modules can be added to scale up net output power without requiring additional equipment or floor space. They are also compact and lightweight allowing users to maximize available installation space without making any major compromises on power storage capacity.
Battery Management System:
Designed for self-consumption, Alpha-ESS batteries offer a comprehensive solution that combines a hybrid inverter, a battery management system and a storage unit. This integrated system allows for the seamless addition of single modules to scale the storage capacity as needed. With the hybrid inverter, solar power generated can be directly utilized in the household or used to charge the battery. Additionally, the inverter enables the conversion of battery power into usable AC power. Alpha-ESS incorporates inverters in their batteries to eliminate additional costs for extra components.
Warranty:
Alpha-ESS systems come with 5 years of product warranty and 10 years of performance warranty.
Range of Inverters and Batteries:
SMILE 5 Hybrid Inverter Single Phase Residential Series Inverter compatible with Low Voltage SMILE Batteries, SMILE5-BAT (5.7kWh Battery), SMILE-BAT-10.3P (10.3kWh Battery) and SMILE-BAT-13.3P (13.3kWh Battery). One can connect up to 6 batteries in parallel, making it expandable to 80kWh.
SMILE-S6-HV Single Phase High Voltage Residential Series Invertercompatible withSMILE-BAT-8.2PH (8.2kWh Battery). One can connect up to 6 batteries in parallel, making it expandable to 49.5kWh.
They both can be installed indoors/outdoors, offer 24X7 monitoring, come with UPS ability and are VPP ready.