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More and more households in Germany are becoming interested in renewable energies. However, not everyone owns a house with roof space for a large photovoltaic system. This is where the balcony power plant comes in. A balcony power plant is a small, plug-and-play solar system specifically designed for apartments, balconies, or terraces. With such a system, tenants or apartment owners can generate their own electricity and simultaneously reduce their electricity costs. The vision behind it: Energy transition in private hands By now, the balcony power plant has become a self-evident term for all of us – we owe this progress primarily to Mr. Holger Laudeley, who, as a pioneer, first launched this groundbreaking idea. Today, the balcony power plant stands for renewable energy for every citizen and is a central building block of the energy transition in private hands. More than 20 years ago, entrepreneur and engineer Holger Laudeley first presented this forward-looking vision to the public. Since then, he has tenaciously campaigned against energy companies, skeptics, and politicians who lack the necessary visionary foresight. His commitment is bearing fruit: the balcony power plant has enjoyed growing popularity for years, and the original vision is now a reality. How does a balcony power plant work? A simple explanation How does a balcony power plant actually work? A balcony power plant consists of a few, but important components: Solar modules: Convert sunlight into direct current. Micro-inverter: The heart of the system. It converts direct current into household alternating current. Mounting system: Holds the modules securely on the railing or terrace. Connection cable: Connects the system directly to your home grid via a standard socket. The principle: The generated electricity flows via the socket directly to your household appliances such as the refrigerator, router, or washing machine. This automatically reduces the amount of expensive electricity you draw from the public grid. How many kWh does an 800-watt balcony power plant provide? How much electricity can a balcony power plant generate per day? Electricity production depends on orientation and solar radiation. A typical 800-watt system in Germany generates on average: 600 to 900 kWh per year. On sunny summer days, this is about 3 to 5 kWh per day. This can cover a significant portion of the daily base consumption (standby devices, Wi-Fi, refrigeration units). When does a balcony power plant pay for itself? Is the purchase financially worthwhile? With costs between €500 and €1,500 and an electricity price of about 30–40 cents per kWh, you save approximately €150 to €300 annually. This means: Many systems have already paid for themselves after 3 to 6 years. Since high-quality modules last over 20 years, you will then produce completely free electricity for over a decade. Does a balcony power plant require approval? Can you simply install a balcony power plant? Thanks to the German government's Solar Package I, use is now very simple: Registration: You only need to briefly register the system in the Market Master Data Register. Notification to the grid operator is no longer necessary. Tenancy law: Tenants now have a legal right to a balcony power plant. Landlords may only prohibit installation in rare exceptional cases. Meter: Old electricity meters may temporarily run backward until the grid operator installs a modern meter. What does a storage unit do for a balcony power plant? What is a balcony power plant with storage? A battery storage system is the ideal addition to significantly increase the self-consumption of solar power. It stores the electricity that you do not consume during the day (e.g., when you are at work) so that you can use it in the evening or at night. Our recommendation for maximum efficiency: Are you looking for a truly powerful system? Then we highly recommend the innovative complete storage systems SunEnergyXT 500 and SunEnergyXT 500 PRO. In the following video, we present these novel all-in-one solutions with durable LFP batteries and integrated inverters. Featuring Holger Laudeley, the inventor of the balcony power plant, and Chengyuan Zhai, CEO of SunEnergyXT. Together, they explain the technology in detail and demonstrate how easily one can become energetically independent today. Here is the video: https://youtu.be/3OPrT01MGJg Which balcony power plant is the best? What should you look for when buying? When buying, pay attention to the following criteria: Module power: 800 watts is the current standard for feed-in. Durability: Choose quality modules with a long lifespan. Expandability: A system that offers the option for a battery storage (like the SunEnergyXT series) is the smarter long-term investment. Safety: Pay attention to certified inverters and stable mounting systems. Conclusion: Is a balcony power plant a good idea? A balcony power plant is the easiest entry into your own energy transition. It is cost-effective, uncomplicated, and, thanks to the pioneering work of individuals like Holger Laudeley, it is now a technical standard. Anyone who wants to reduce their electricity bill and protect the climate at the same time will find the ideal solution here. Would you like to learn more about the installation or do you have questions about the SunEnergyXT storage systems? Please feel free to contact us!

For tech-savvy users with balcony power plants or small solar systems, OpenDTU is no longer an insider tip. The project enables the monitoring of Hoymiles micro-inverters without the data being transferred to a manufacturer cloud. In this article, we explain which inverters are suitable for OpenDTU, how data can be read live, and why this solution is particularly suitable for home and balcony power plants. Market Trends in Decentralized Energy Monitoring The market for balcony power plants and mini-PV systems is growing rapidly in Germany. Many users want to know how much solar power is generated per day, week, or month, without relying on a proprietary app or cloud services. Energy industry studies show that more and more private users prefer their own monitoring solutions that can be integrated into home automation systems like Home Assistant or into their own visualizations via MQTT. At the same time, demand for compatible inverters that work with OpenDTU or similar DIY DTUs is increasing. Hoymiles micro-inverters are particularly in demand, as they enable modular, compact systems for balcony power plants and small rooftop installations. Why OpenDTU is attractive to tech-oriented users OpenDTU is a DIY-based DTU solution that communicates via the radio interface of Hoymiles micro-inverters. Unlike many manufacturer clouds, communication remains local within the home network or private WLAN, so no data is automatically sent to the internet. Key advantages include: Real-time monitoring of generation, voltage, frequency, and power of individual modules. No obligation to use a cloud platform or manufacturer app. Integration into custom visualization tools such as Grafana, Home Assistant, or PV dashboard with MQTT. This combination makes OpenDTU particularly interesting for technically adept users who want to control and analyze their balcony power plants or small PV systems themselves. OpenDTU Compatible Inverters: Overview and Models OpenDTU was primarily developed for Hoymiles micro-inverters, but some variants now also support other brands such as TSUN or Solenso. It is important that the inverter has a radio interface and does not include an integrated WLAN function in its type name (e.g., "W" in the model designation for Hoymiles). For German use and typical balcony power plants, the following series are particularly relevant: Hoymiles HM series (2.4 GHz radio): HM-300, HM-350, HM-400, HM-600, HM-700, HM-800, HM-1000, HM-1200, HM-1500These models are classic micro-inverters for PV modules in the range of 300 to 1500 watts per device and are supported by many OpenDTU variants. Hoymiles HMS series (900 MHz radio): HMS-300, HMS-350, HMS-400, HMS-450, HMS-500, HMS-600, HMS-700, HMS-800, HMS-900, HMS-1000, HMS-1600, HMS-1800, HMS-2000These devices work with a separate radio module and are also suitable for OpenDTU, as long as no WLAN is integrated. Hoymiles HMT series (900 MHz radio): HMT-1600, HMT-1800, HMT-2000, HMT-1800-6T, HMT-2250-6TThese are slightly simplified variants designed for smaller or medium-sized balcony power plants. Other brands (partially open-source confirmed): TSUN TSOL-M350, TSOL-M800, TSOL-M1600 Solenso SOL-H350, SOL-H400, SOL-H800 Please note that not all devices with an integrated WLAN module (e.g., Hoymiles models with "W" in the name) are recognized by OpenDTU. Most of these WLAN variants are currently considered incompatible. Top products for OpenDTU users In the field of microinverters and balcony power plants, the main differences are in the power class, radio frequency, and the number of connectable modules. Below are some typical models that are mentioned as OpenDTU-compatible in practical reports and community documentation. Hoymiles HM-300: Power up to 300 W, one module per device, 2.4 GHz radio, ideal for small balcony or terrace systems. Users appreciate the low entry barrier and easy installation, often in the range of 1-2 modules per balcony. Hoymiles HM-800: Power up to 800 W, two modules per device, also with 2.4 GHz radio. Suitable for slightly larger balcony systems with higher expected yield and often in combination with proprietary PV software. Hoymiles HMS-800: Power up to 800 W, two modules, 900 MHz radio. Many users report stable data transmissions and good integration into OpenDTU firmware. Hoymiles HMS-1600: Power up to 1600 W, four modules per device, 900 MHz radio. Interesting for larger balcony or small rooftop systems where multiple modules are to be centrally bundled. TSUN TSOL-M800: Power up to 800 W, two modules, radio communication with OpenDTU after firmware verification. Mentioned as a cheaper alternative to Hoymiles micro-inverters, especially in community projects. These models are available from many specialist dealers and online shops and are regularly confirmed as OpenDTU-compatible by the community. Please check the current product description and firmware version, as manufacturers may implement updates. Differences between OpenDTU variants and inverters OpenDTU itself comes in several variants, which differ in radio frequency and supported series. Standard OpenDTU (2.4 GHz): Primarily supports HM series, possibly also individual Solenso and TSUN models. Simple construction, often available as a DIY kit or pre-built board. OpenDTU with 900 MHz radio module (CMT2300A): For HMS and HMT series, as these communicate at 900 MHz. Slightly more expensive than the standard version, but broader for most modern Hoymiles micro-inverters. OpenDTU Fusion / Hybrid variants: Support both 2.4 GHz and 900 MHz radio, covering both HM and HMS/HMT devices. Very popular with users who use multiple inverter series in one system. An OpenDTU environment can usually monitor several inverters simultaneously, typically up to ten devices per instance. The exact number depends on the firmware and hardware set used. How to monitor your data live with OpenDTU Setting up OpenDTU typically involves several steps: Hardware selection: Purchase a suitable OpenDTU board or a ready-made kit (2.4 GHz or 900 MHz). Matching the compatible inverter series (HM, HMS, or HMT) with the DTU variant. Connection and configuration: Feeding the OpenDTU into the local network via WLAN or LAN. Uploading the latest OpenDTU firmware via the integrated web interface. Inverter Discovery: OpenDTU scans the radio frequency and automatically detects connected Hoymiles microinverters. Each inverter receives an ID, which is stored in the system. Data transfer via MQTT: Configuration of an MQTT broker (e.g., on a Raspi or NAS) and connection of the OpenDTU. Generation of topics via which power, voltage, frequency, and status values are published per device. Visualization: Integration of MQTT data into tools like Home Assistant, Node-RED, or Grafana. Creation of custom dashboards with daily, weekly, or annual power yield, as well as feed-in and self-consumption key figures. Many users report that after just a few hours of setup, they already have stable real-time monitoring of their balcony power plants or small systems. The fluctuations in generation during the day can thus be precisely tracked and linked to household consumption. Important aspects when selecting an OpenDTU-compatible inverter Before selecting a specific inverter for your balcony power plant or small PV system, you should check a few points: Radio frequency and DTU type: HM models with 2.4 GHz require a corresponding OpenDTU variant. HMS/HMT devices with 900 MHz require a DTU with a suitable radio module. WLAN function in the model name: Devices with "W" in the name (e.g., HMS-800W) are usually not OpenDTU-compatible, as they communicate via their own WLAN interface. Instead, use the non-WLAN versions (e.g., HM-800 or HMS-800 without "W"). Number of modules per device: HM-300/HM-350: one module per device. HM-800/HMS-800: two modules per device. HM-1500/HMS-1600/HMS-1800: four modules per device. This selection has a direct impact on installation (cabling, cable length, fusing concept) as well as on data visualization, as individual modules can be displayed as separate units. Application examples for balcony power plants with OpenDTU Balcony power plants with OpenDTU are primarily used in households and rented apartments where larger rooftop systems are not feasible. One-module balcony power plant: A solar module with 350–400 watts and an HM-350 inverter is sufficient for many balconies. OpenDTU monitors generation live and shows how self-consumption changes throughout the day. Two-module balcony: Two modules with an HM-800 or HMS-800 generate up to 800 watts maximum. Such systems can be well integrated into Home Assistant dashboards and linked with smart home switches for consumers. Mini rooftop system on a small carport: Several modules distributed across HM-1500 or HMS-1800 devices, combined with an OpenDTU Fusion. Users report that they can thus directly compare the yield season in summer and winter and optimize their consumption. In many cases, users not only reduce their electricity consumption but also gain a better understanding of the dynamics of their PV system. DRBO Greenenergy: Tech-savvy solutions for balcony and mini solar systems Before the "Application Examples" section, tech-savvy providers specializing in balcony power plants and small PV systems can be included. DRBO Greenenergy is one of them: The company supplies microinverters, solar modules, and balcony storage solutions to both specialist retailers and private customers. With plug-and-play balcony power plants, bidirectional inverters, and refurbished energy storage systems with Deye inverters, DRBO Greenenergy offers solutions that can be easily integrated into custom monitoring concepts such as OpenDTU. Particularly interesting for technically savvy users are the compact balcony power plant packages with field-proven microinverters that can be installed and monitored live with little effort. Buying Guide: What to look for in OpenDTU-compatible inverters When choosing an inverter for OpenDTU, you should check the following points: Compatibility list: Check the official OpenDTU documentation or community documentation to see if your desired model is explicitly listed. Integrated radio frequency (2.4 GHz vs. 900 MHz) must match the OpenDTU board. Power class and system planning: Decide early whether you want to use single-module or multi-module devices. Individual modules allow more detailed logging data, while multiple modules per device reduce the number of inverters required. Safety and protection: Pay attention to suitable overvoltage and fine distribution, especially for rooftop systems or carports. If installation is to be carried out on the mains side or in the house distribution, consult a qualified electrician. For properly planned balcony power plants with OpenDTU, this results in safe, well-monitored, and easily expandable systems. Future trends: OpenDTU, home energy monitoring and balcony power plants The development of OpenDTU and similar DIY monitoring solutions shows that the trend towards local, cloud-free systems continues. Manufacturers like Hoymiles and TSUN are responding with adapted firmware versions and new radio interfaces, which further influences compatibility with OpenDTU variants. In the long term, balcony power plants and mini PV systems will be increasingly integrated into home automation ecosystems: Real-time control of consumers based on current PV generation. Linking with battery storage systems and heat pumps to maximize self-consumption. Automatic logging of yield data for analysis over years.