Nowadays there are two types of energy storage system for residential, high voltage system and low voltage system, we might be wondering which type is optimized when considering to equip our homes with solar and ESS. Here comes some tips for your reference.

What is a High Voltage (HV) battery?
In the energy storage system, we usually define the battery system with a rated voltage in the range of 90V-1000V as a high voltage system. Such energy storage systems are often used for larger energy needs, such as commercial and industrial energy storage, electric vehicle charging stations, etc. Paired with a three-phase hybrid inverter, it can handle high power loads and provide greater efficiency and performance in systems that require large amounts of energy to be output for long periods of time.

What are the advantages of high voltage batteries?
Higher transmission efficiency
One of the advantages of high-voltage batteries is to improve the energy transfer efficiency of the storage system. In energy-demanding applications, the increased voltage means that the storage system requires less current to deliver the same amount of power, which reduces the amount of heat generated when the battery system is operating and avoids unnecessary energy loss. This increase in efficiency is particularly important for energy storage systems exceeding 100kWh.

Greater scalability
High-voltage battery systems are also scalable, but are typically based on larger battery capacities, ranging from 15kWh to 200kWh for a single battery pack, making them the first choice for small manufacturers, solar farms, community power, microgrids, and more.

Reduce cable size and cost
Due to the increase in voltage, the same amount of electricity produces less current, so the high-voltage battery system does not need to make more sinks, so only need to use a smaller size of the cable, thus saving material costs, and greatly reduce the complexity of the system installation.

Better performance in high power applications
In EV charging stations, industrial manufacturers, and grid-scale energy storage applications that often involve high power output, high-voltage battery systems are very good at handling high-power surges, which can greatly improve the stability and reliability of an organization's power consumption, thereby protecting critical loads, improving efficiency, and reducing costs.

Disadvantages of high voltage battery system
Of course, everything has two sides, and the high-voltage battery system also has its own disadvantages:

Security risk
The biggest disadvantage of high-voltage battery systems is the increased system risk. When operating and installing a high-voltage battery system, you need to wear protective insulation clothing to avoid high-voltage electric shocks.

Tip: High-voltage battery systems require more stringent safety procedures, including specialized circuit protection, insulation tools, and trained installation and maintenance technicians.

Higher upfront cost
While high voltage energy storage systems improve battery and energy conversion efficiency, the complexity of the system components (additional safety equipment and protection features) increases the upfront investment cost. Each high voltage system has its own high voltage box, using the master-slave architecture for battery data acquisition and control, while the low voltage battery system has no high voltage box.

What is a low-voltage battery?
In energy storage applications, batteries that typically operate at 12V - 60V are called low-voltage batteries, and they are commonly used in off-grid solar solutions such as RV batteries, residential energy storage, telecom base stations, and UPS. The battery system commonly used for residential energy storage is generally 48V or 51.2V. When the low-voltage battery system is used for expansion, the batteries can only be connected in parallel, so the system voltage does not change. Low-voltage batteries are often used in situations where safety, ease of installation, and economy are key considerations, especially in systems that do not require significant continuous power output.

Advantages of low-voltage batteries
Enhanced security
Safety is often one of the top considerations for homeowners when choosing an energy storage system, and low-voltage battery systems are favored for their inherent safety. Low voltage levels effectively reduce battery risk during installation, use, and maintenance, making low-voltage batteries the most common and commonly used battery type for home energy storage applications.

Higher economy
Low-voltage batteries are more cost-effective due to their lower BMS requirements and more mature technology, which makes them less costly. Similarly, the system design and installation of low-voltage batteries are simpler and the installation requirements are lower, so installers can deliver faster and save installation costs.

Suitable for small energy storage
For homeowners with rooftop solar panels or businesses that need backup power for critical systems, low-voltage batteries are a reliable and efficient energy storage solution. Being able to store excess solar energy during the day and use it during peak hours or power outages is a major advantage, allowing users to save on energy costs and reduce their dependence on the grid.

Disadvantages of low voltage battery system
Low efficiency
Energy transfer efficiency is typically lower than in high-voltage battery systems because higher currents are required to deliver the same amount of power, which leads to higher temperatures in the cables and connections as well as the internal battery, resulting in unnecessary energy loss.

Higher expansion costs
Low-voltage battery systems are scaled in parallel, so the voltage of the system remains the same, but the current is multiplied, so in multiple parallel installations you need thicker cables to handle higher currents, which leads to higher material costs, and the more parallel the system, the more complex the installation. In general, if more than 2 batteries are connected in parallel, we recommend that the customer use a bus or bus box for installation.

Limited scalability
The scalability of low-voltage battery systems is limited because the efficiency of the system will become less and less as the number of batteries increases, and the large amount of data to be collected between cells will also be slower to process. Therefore, for larger energy storage systems, it is recommended to use high-voltage battery systems, which are more reliable.

Which is best for your storage needs?
Both high-voltage and low-voltage battery systems have their unique advantages, and there are many major factors to consider when choosing an energy storage system, including energy requirements, budget, and safety considerations.

However, if you are just starting out with a different app, we recommend that you choose based on the following:

Low voltage battery system:
Residential solar storage: Electricity is stored during the day for use during peak demand or at night.
Emergency backup power: Keep essential appliances and equipment running during a power outage or blackout.
High voltage battery system:
Commercial energy storage: Ideal for companies with large solar arrays, wind farms, or other renewable energy projects.
Electric vehicle (EV) infrastructure: High-voltage batteries are ideal for powering EV charging stations or fleets.
Grid-level storage: Utilities and energy service providers typically rely on high-voltage systems to manage large amounts of energy flow and ensure grid stability.

In summary, families with a large population, large power load, and high charging time requirements consider choosing high-voltage energy storage batteries, and conversely, choose low-voltage energy storage batteries. By carefully assessing your energy storage needs, whether for a home solar system or a large commercial installation, you can choose a battery that meets your goals, ensuring long-term efficiency and reliability.