Which storage solution is right for your balcony power plant? The SunEnergyXT 500 Series & the new AC Core 500 in comparison

Which storage solution suits your balcony power plant? The SunEnergyXT 500 Series & the new AC Core 500 in comparison

The energy transition in Germany is no longer just happening on large open spaces or rooftops, but directly on balconies. Hundreds of thousands of households have installed simple plug-and-play solar systems in recent years. While the first generations of these balcony power plants were primarily designed to cover the so-called base load during the day, a new goal is moving into the foreground with rising electricity prices and intelligent metering technology: maximizing the self-consumption of self-generated energy throughout the entire day and night.

Without a suitable storage system, a significant portion of the solar power generated at noon flows uncompensated into the public grid. Those who want to increase their self-sufficiency therefore face the question of which storage concept best suits their household, both technically and economically. In this context, integrated all-in-one systems and specialized AC-coupled retrofit storage systems have established themselves as key solutions.

The Trend Towards Retrofitting: Challenges for Existing Systems

Many solar pioneers who commissioned a balcony power plant several years ago now face a specific challenge. The existing microinverters and solar modules are technically sound. A complete replacement of the system to integrate a DC storage system (DC coupling) would be economically unprofitable and environmentally unwise.

This is where the principle of AC coupling comes into play. An AC-coupled storage unit is not connected directly between the solar module and the inverter but taps the energy on the AC side in the house grid. This allows for complete decoupling from the existing solar hardware on the roof or balcony. The challenge so far has primarily been the price: powerful AC storage systems were primarily designed for large-scale systems and were simply oversized and too costly for simple balcony setups.

SunEnergyXT 500 Series: The All-in-One Powerhouse for New Installations

For users who are planning a new installation or want to fundamentally upgrade their existing setup, the SunEnergyXT 500 Series, introduced three months ago, offers a comprehensive overall package. The SunEnergyXT 500 and 500 PRO each combine four independent MPPT trackers, an inverter and a 5 kWh-class storage unit in one housing. Rated grid output is 800 W for the 500 and 2,400 W for the 500 PRO. The 5 kWh figure describes the capacity class, not the usable capacity.

The Core Features of the SunEnergyXT 500 Series in Detail:

1. All-in-One Architecture: Integration of four MPPT inputs, an inverter and 5 kWh-class storage. Grid output is 800 W for the 500 and 2,400 W for the 500 PRO. Grid and backup connections must be used according to the model and the planned installation.

2. Connection and Commissioning: Connection and commissioning depend on the model, the manufacturer's instructions and local requirements. Have a qualified electrician assess any required electrical work beforehand.

3. Flexible Scalability: The system can be modularly adapted to increasing energy demands with additional main units or expansion batteries.

4. Model-dependent Backup Power: Availability, switchover time and supported loads depend on the model, operating mode and connection arrangement. A backup function does not automatically provide uninterrupted power to the entire home.

5. Long-lasting Cell Chemistry: For the SunEnergyXT 500 series, the user manual specifies at least 10,000 charge cycles under these test conditions: 25 ± 2 °C, 80% depth of discharge (DoD), 0.5C charging and 0.5C discharging, with 70% remaining capacity at end of life (EoL). Actual service life depends on use and environmental conditions.

6. Smart Control & Integration: Full app monitoring, local control options, and seamless integration into open-source systems like Home Assistant.

7. Your Home Energy Hub: Direct communication with the smart meter enables automated optimization of household electricity consumption.

Detailed technical data sheet information and configuration options for the model series can be found directly on the official SunEnergyXT 500 product page.

AC Core 500: Efficient Storage Retrofit and "Peak Shaving"

To specifically address the needs of the retrofit market (existing systems), the portfolio has been expanded to include the AC Core 500 variant. This model focuses on highly efficient AC charging via the house grid. The storage unit has a nominal energy capacity of 5,024 Wh and a usable capacity of 4.8 kWh.

A key advantage of the AC Core 500 lies in its use of modern electricity tariff structures. In addition to storing one's own balcony electricity, the device enables intelligent "peak shaving" and the utilization of dynamic electricity tariffs:

• Peak Shaving: The storage unit absorbs surplus yields from the existing solar system during peak generation times during the day and makes them available precisely when household consumption increases in the evening.

• Optimization of Variable Electricity Tariffs: In combination with a smart meter, the storage unit can be charged during periods of low grid electricity prices (e.g., at night or when there is high wind energy feed-in) to supply the household during expensive peak times.

The four MPPT solar inputs on the 500 PRO AC Core are disabled at the factory. The manufacturer offers an optional upgrade to activate them for a one-time service fee per main storage unit; it is not a subscription. The direct PV input can only be used after activation. The selected solar panels and their wiring must comply with the device's electrical limits.

Function Comparison: SunEnergyXT 500 Series vs. AC Core 500

Function Area	SunEnergyXT 500 / 500 PRO (All-in-One)	AC Core 500 (AC-Couple)
Main Application	New installations & complete upgrades	Retrofit of existing PV/balcony systems
Battery Capacity	5 kWh class (scalable)	5 kWh class (scalable)
Cell Technology	EVE Premium (≥10,000 cycles under the test conditions stated above)	EVE Premium (≥10,000 cycles under the test conditions stated above)
Emergency Power (UPS)	Depends on model and connection; refer to the relevant datasheet	UPS mode: ≤10 ms; outside UPS mode: <2 s. Appropriately connected loads only
Smart Meter Integration	Yes (Automatic energy management)	Yes (Optimized for Peak Shaving)
Home Assistant Connection	Yes (Local control & App)	Yes (Local control & App)
4× MPPT Solar Inputs	Integrated & active from factory	Disabled at the factory; activation through a one-time paid upgrade, not a subscription
Price-Performance Profile	Maximum functionality from day 1	Particularly economical entry

Both variants are based on the same robust hardware platform and share the connectivity options to the smart meter as well as the integration into smart home systems such as Home Assistant. Further information on the exact differences and package options can be found on the common model overview for the SunEnergyXT 500 Series.

Conclusion & Purchase Recommendation

The decision between the two systems largely depends on the existing conditions:

• Choose the SunEnergyXT 500 Series if you are planning a new installation, want to connect solar panels through the MPPT inputs, and are looking for an integrated all-in-one solution. Check module compatibility and the connection arrangement required for the model.

• Choose the AC Core 500 if you already operate an existing balcony solar system, want to keep investment costs low, and are looking for a highly efficient 5 kWh storage unit that sustainably reduces your electricity bill through intelligent grid and solar storage.

With both models, SunEnergyXT offers two of the currently most attractive and flexible storage solutions on the German market, which can be seamlessly adapted to the individual requirements of modern households.