Demystifying AC Coupled Inverters: A Comprehensive Guide
Before introducing AC-coupled inverters, it is helpful to first understand the distinction between DC-coupled and AC-coupled systems.
A variety of solar-plus-storage configurations—commonly referred to as PV storage systems—are available on the market. These systems typically include PV panels, inverters, batteries, and loads. Although there are multiple ways to design a PV storage system, energy in each configuration must converge at a common point. The two primary architectural categories are AC-coupled inverters (also referred to as AC coupling inverters) and DC-coupled inverters.
In an AC-coupled solar system, the integration of battery storage is achieved through AC-coupled battery storage solutions. This type of setup, frequently described as AC coupling solar or simply AC coupling, utilizes an AC-coupled battery unit, which enhances system flexibility and simplifies integration.
What is an AC Coupled Inverter?
An AC coupling inverter is the key component that enables AC-coupled battery storage in an AC-coupled solar system. In this AC coupling architecture, two inverters work in tandem: a solar inverter converts DC power from PV panels to AC electricity for immediate use, while a bidirectional battery inverter manages the AC-coupled battery by converting excess AC power back to DC for storage, and then DC to AC when discharge is needed. This AC coupling solar approach provides greater flexibility for system expansion and retrofit applications.
AC-Coupled Inverters: The Smart Choice for Solar Expansion and Backup
Considering adding energy storage to your existing solar array, or planning a new installation that prioritizes future expansion and blackout protection? AC-coupled inverters could be the versatile solution you need. While not universal, their unique architecture provides distinct benefits for specific applications. This article will help you determine if an AC-coupled system aligns with your energy goals.
How AC Coupling Works: The Intelligent Energy Manager
Think of AC coupling as a sophisticated "energy traffic controller" for your home. Unlike a standard DC-coupled system where solar panels send power through a single inverter, AC-coupled inverters create a more intelligent, two-layer system:
Solar Production: Your solar panels connect to their own dedicated solar inverter(s), which convert sunlight to AC electricity. This part of the system operates independently.
Centralized Management: The generated AC power, along with grid electricity, flows to the AC-coupled inverter. This device acts as the core intelligence for storage and backup, operating in three key modes:
Mode 1: Sunshine & Savings: During the day, solar power runs your home. The AC-coupled inverter directs any surplus AC electricity to charge the battery storage (by converting it to DC).
Mode 2: Blackout Resilience: If the grid fails, the AC-coupled inverter instantly isolates the home to form a safe microgrid. It generates a stable grid signal that allows your existing solar inverters to continue operating—a key advantage over many DC-coupled systems, enabling solar use during an outage.
Mode 3: Nighttime Power: After sunset, the inverter draws energy from the AC-coupled battery storage, converting DC back to AC to power your essential loads.
Simplifying the Upgrade with Integrated Solutions
Historically, configuring such a system could be complex. However, integrated AC-coupled solar system solutions like the PowerGo series have simplified this immensely. The PowerGo is an AC-Coupled All-in-One unit that combines the inverter and lithium batteries into a single, compact cabinet with plug-and-play functionality.
For homeowners with an existing solar system, adding a PowerGo unit is remarkably straightforward. It is designed to integrate with your existing PV inverter, typically requiring no major modifications to the original solar wiring. This approach significantly reduces installation time and cost, making the benefits of AC coupling solar—enhanced energy independence and reliable backup power—more accessible than ever.
In summary, AC coupling represents a system design that prioritizes flexibility and resilience, and modern solutions are making this advanced approach increasingly practical for a wider range of homeowners.
PowerGo 2,5kWh & 5,0kWh
PowerGo offers flexible capacity options with 2.5kWh and 5kWh models, including a 5kWh off-grid version. This standalone AC battery storage system works right out of the box - simply plug in to power devices with 1600W AC output or use 800W grid-tied output to save on electricity bills. Perfect for retrofit expansion, it integrates easily with existing solar systems. All models feature safe LFP battery technology for reliable home energy management.
Learn moreWide Range of Applications
AC-coupled inverters are highly adaptable and can be used in:
• Residential spaces (e.g., living rooms, balconies, kitchens) where compact solar storage is needed.
• Remote locations (e.g., farms, islands, mines) where grid stability is unreliable.
• Commercial settings where modular expansion is preferred.
Note: Specific use cases depend on whether the inverter is designed for off-grid, grid-tied, or hybrid applications.
Key Advantages
Safety Protection
Reduces risks from high DC voltage on the battery and PV sides, ensuring system safety.
High Efficiency
When solar production matches daytime demand, power can be directly used, achieving >96% efficiency.
Optimizes low-voltage battery conversion efficiency up to 96.5%.
Scalability & Flexibility
Supports parallel expansion, making it easy to increase capacity without major system redesigns.
Compatible with various energy storage configurations.
What is DC coupled inverters
In the DC coupling system, photovoltaic modules and energy storage batteries connect directly to a hybrid inverter. This type of system employers an MPPT (Maximum Power Point Tracker) controller, which stores the energy created by the photovoltaic panels into the batteries. The energy in such systems is stored on the DC side, hence, the system is named DC-coupled.
This schematic diagram of the hybrid inverter can also be more simplified as the rooftop energy storage power station system, and you can have a clearer understanding through this article.
Dc coupled inverters vs Ac coupled inverters
Generally, AC-coupled inverters are mainly used in existing installations, such as homes that already have a PV system and want to add an energy storage system. DC-coupled systems are typically used for new installations, like setting up a completely new pv storage system from scratch.
Energy Utilization Efficiency: DC Coupled inverters Surpasses AC-Coupled Inverters
In an AC-coupled inverters, solar energy is stored in the battery after undergoing two conversions—DC-to-AC, AC-to-DC, and another DC-to-AC transformation when the battery releases energy. This three-step conversion process results in significant system energy loss, with an overall efficiency of around 90%.
In contrast, DC coupling charges the battery through an MPPT, leading to extremely low energy loss during the DC-to-DC conversion. When energy is released, it only requires one DC-to-AC conversion through a hybrid inverter, achieving an overall efficiency of over 97%.
Cost: DC Coupled inverters Are More Cost-Effective Than AC-Coupled Systems
At first glance, AC Coupled inverters requires the use of two inverters, while DC coupling requires only one. Additionally, DC coupling allows for an integrated energy storage system, offering advantages in both equipment and installation costs.
System Flexibility：AC coupled inverters have an upper hand.
In AC coupled inverters, the modules are in a parallel state, making it very convenient to add or remove modules, such as adding a new set of PV systems or energy storage systems. These can be directly incorporated without the need for additional system design adjustments. On the other hand, DC coupled inverters modules are in a serial state, connected closely to each other, making adding or removing modules more complex.
Scenarios for AC Coupled Inverters in Batterlution PowerGo All-in-One Energy Storage Systems
1.Homes Without Solar Energy Backup Battery Systems:
In regions with significant peak and off-peak electricity price differences, the Batterlution PowerGo AC coupled inverter offers an ideal backup power solution — even without solar panels. Designed with standard AC power cords and plug terminals, it requires no additional wiring or electrical modifications, delivering true plug-and-play functionality. As an efficient AC coupled battery system, it charges during low-rate periods and discharges during high-cost hours, helping households significantly reduce electricity expenses while providing reliable battery backup systems support during grid outages.
2. Enhanced Expansion for Existing Solar Power Systems:
For homes with existing solar panels, the Batterlution PowerGo series provides a convenient energy storage upgrade that works alongside current PV systems. Featuring standard AC power cords and plug terminals, it eliminates the need for specialized wiring or grid modifications. Simply connect to a standard Schuko AC outlet, and start storing surplus solar energy immediately. This practical AC on battery solution enables effective capture of excess solar energy that would otherwise be fed back to the grid, enhancing energy self-consumption and household energy independence through a straightforward installation process.
AC-Coupled Inverter Advantages for Whole-Home Battery Backup (Non-Solar Applications)
While solar panels and home battery backup are frequently paired, a home battery system utilizing an AC-coupled inverter offers significant benefits even without solar. This configuration simplifies integration with existing home electrical systems and provides exceptional flexibility for future solar additions. Below are the key advantages of this setup:
Load shifting/Peak shaving
This refers to charging the battery to store energy during off-peak hours when utility rates are low, later using this stored energy during peak hours when rates are high. Implementing this strategy can help manage and reduce your electricity bills.
Emergency backup
One of the main reasons people invest in home battery backup systems is to provide power during outages. With increasingly frequent power cuts due to aging infrastructure and severe weather conditions, this feature has become crucial.
Reducing reliance on the grid
While typically associated with solar, a battery system alone can also diminish grid dependence. It provides a buffer against volatile electricity prices. Furthermore, by pairing with an AC-coupled inverter, the system is perfectly poised for the future addition of solar panels, creating a comprehensive solution to counter grid instability and move away from fossil fuels.
With the 2.5kWh AC coupled storage battery, you can buy power at the lowest price to fully meet the home load needs. Therefore, whenever you enjoy the lowest electricity price, even if the peak electricity price in your area is extremely high.
