The STABL technology

Are you an employee of a storage manufacturer or a tech-savvy end customer? Find out more about the STABL Energy inverter technology for battery storage on this page and download our white paper today.

Inverterinnovation for battery storage from STABL Energy

Inverters from STABL Energy are more than just a component of a battery storage system. Thanks to the innovative modular approach, they simplify the design of electricity storage systems and enable a low-cost, sustainable energy supply for trade and industry. Compared to conventional products, energy losses are reduced by up to 70 % and operating costs are cut by up to 40 % – all with almost the same investment costs. Find out more about the technology and what is behind the award-winning inverters here. 

Conventional electricity storage systems

Architektur eines Hochvoltspeichers mit zentralem Wechselrichter
High Voltage Storage

Conventional storage systems consist of hard-wired battery modules. 

All battery modules must be from the same series and have the same states, internal resistance and state of health. 

If one battery module fails, the entire storage system fails.

Central Inverter

The central inverter requires high input voltages. This is the only reason why battery storage systems are built the way they are. 

Conventional inverters for battery storage systems are too inefficient and require too much space.

Architektur eines Hochvoltspeichers mit zentralem Wechselrichter

Conventional electricity storage systems consist of a high-voltage battery pack and a central inverter. 

Several permanently interconnected modules form the battery pack, which can have life-threatening voltages of up to 800 V. The central inverter converts this DC voltage into AC voltage suitable for the grid and thus connects the storage system to the power grid. This results in energy losses that cost the operator money and also increase CO2 emissions.

Inverter technology from STABL

Architektur eines Batteriespeichers mit STABL Wechselrichter
The STABL module

We decouple the battery modules from each other, and each battery module is connected to a STABL module.

The STABL Master

The STABL modules are dynamically interconnected. The STABL master receives the commands from the energy management system and orchestrates the interconnection.

Independent battery modules

The battery modules are independent of each other thanks to the new design. This means that modules in different states can also be installed in one storage unit.

Less space required

The STABL modules can be easily integrated into your existing rack concept. No additional space required due to an inverter, just the size of a refrigerator.

Architektur eines Batteriespeichers mit STABL Wechselrichter

With the inverter technology from STABL Energy, the construction of electricity storage systems is significantly simplified. Instead of connecting the modules together statically, our STABL modules connect them together dynamically. 

The energy storage system is a conglomerate of absolutely safe battery modules with touch-safe voltages of less than 60 V. This approach eliminates the need for the central inverter. Compared to conventional systems, losses are reduced by up to 70 % and both operating costs and CO2 emissions are reduced by up to 40 % per year.

The advantages of STABL technology


The high efficiency of the STABL inverter of up to 99.4 % was determined in scientific studies held at the Technical University of Munich. Compared to conventional inverters, losses are reduced by up to 70 %.

Save Money

The high efficiency saves you money. Depending on the application, you can reduce your operating costs by up to 40 % by using battery storage systems with STABL inverters and reach your break-even point earlier than with other systems.


Less energy loss also means that the available energy is better utilized. By reducing losses by up to 70 %, CO2 is saved with every storage process and you, and your business actively participate in the energy transition - and save money at the same time.


Battery storage systems are safe with inverters from STABL Energy. The touch-safe voltage of less than 60 V makes installation and maintenance child's play.


The modular approach, coupled with our stringent quality assurance, ensures almost complete availability. Our STABL modules automatically detect when a battery module deviates from its normal state and can isolate it from the rest of the storage system. This means that the entire storage system does not have to be shut down due to a defective module but can continue to be operated.

Cloud Architecture

Inverters from STABL Energy are intelligent and future-oriented. Our in-house developed software enables over-the-air updates and gives you insights down to cell level at any time.

Working Principle

The inverters offered by STABL Energy exceed the role of a mere component in a battery storage system.

Conventional electricity storage systems

Wechselstrom mit konventionellem Wechselrichter
High-voltage battery

The dangerous high-voltage battery pack is switched on and off - regardless of the target voltage required.

Target voltage

The grid wants a perfect sine wave voltage.

Output voltage

Conventional inverters switch the full battery voltage on and off periodically. This is inefficient and dangerous. In addition, the resulting pulse pattern must first be filtered so that the output voltage of the inverter is grid-compliant.

Wechselstrom mit konventionellem Wechselrichter

Normal battery inverters switch the high voltage of the power storage unit on and off for different lengths of time. This process is called pulse width modulation. The resulting voltage must be smoothed by a so-called grid filter so that it complies with the standards and requirements of the power grid. This costs efficiency and causes losses. 

Inverter technology from STABL

Wechselstrom mit Wechselrichter für Batteriespeicher von STABL Energy
Module control

Instead of using the dangerous static HV battery pack, safe battery modules are dynamically interconnected to generate the output voltage.

High-resolution staircase voltage

Depending on which voltage value is currently required, the STABL technology first switches one, then two, then three, etc. battery modules in series. This generates a staircase voltage that is much more similar to a sine wave than the pulse pattern on the left.

The result: more efficiency for you and your customers. 

Flexible voltage output

The frequency and form of the voltage is completely flexible. The STABL inverter can also output DC voltage, 60 Hz sine wave or a staircase voltage.

Wechselstrom mit Wechselrichter für Batteriespeicher von STABL Energy

In science, STABL Energy’s approach is referred to as a “Modular Multilevel Inverter” and is widely used in high-voltage direct current transmission. STABL Energy was the first company to optimize it for battery storage systems. Here, the sine wave voltage is simulated by connecting the individual battery modules in series one after the other. The staircase voltage generated in this way is much more similar to the desired grid voltage than that of conventional inverters for battery storage systems. This means that the grid filter can be smaller, and losses are minimized.

Loss-free Balancing

In conventional battery storage systems, the weakest cell determines the performance of the storage system. With increasing use, the maximum capacities of the battery cells drift apart and so the cell with the lowest capacity determines the capacity with which the remaining cells can be charged. Although the capacities can be redistributed through balancing, this costs energy and causes further losses. 

With STABL Energy’s modular approach, the weakest cells no longer affect the entire storage system, but only the module level. Furthermore, the modules are charged and discharged according to their individual state of charge, so that the charge levels of the modules automatically align with one another. This allows you to get more energy out of your storage system and use it for longer than conventional storage systems.

Comparison of efficiency curves

Efficiency up to 99.4%

Proof of functionality​​

In a master’s thesis at the Technical University of Munich, the efficiency of our modular design was tested and compared to that of a conventional inverter. 

The results show a very high efficiency of our approach of up to 99.4 %. Compared to a conventional central inverter of a battery storage system, higher efficiencies were shown across the entire power range, which is mainly due to the significantly lower switching voltages and frequencies. Instead of switching the entire voltage of a high-voltage pack, STABL technology generates the AC voltage by dynamically connecting and disconnecting low-voltage battery modules. Another advantage of STABL technology is the significantly lower Total Harmonic Distortion (THD) before filtering. The values achieved make it possible to install smaller, cheaper and more efficient filters. 

The high conversion efficiency has an effect on the efficiency of the entire storage system and thus reduces the Levelized Cost of Energy (LCOE), enabling an earlier and higher return on investment. 

Further advantages, possible applications & outlook

Deep battery analytics

The STABL modules can measure the battery modules during operation and automatically store the data in the STABL Cloud. STABL Energy generates the most accurate data on health status, temperature, current and voltage in real time, helping battery manufacturers to monitor the performance of their cells. For example, battery manufacturers can detect faults in certain batches or find out which external circumstances have which effects on the cells. Insurers also benefit from this data, as it enables a reliable risk assessment and insurance, and reinsurance companies can use it to design attractive insurance policies. 


Second-life capability

Returns of used vehicle batteries will pose a major challenge for the economy and the environment. In fact, batteries from electric cars are deemed unsuitable as soon as they still contain 80% of their original capacity. However, these batteries are still suitable for stationary systems, and it is estimated that they can be operated for up to ten years. With the modularity of STABL Energy’s inverter technology, second-life storage systems can be operated more efficiently and cost-effectively than with conventional inverters for battery storage systems.


Wide range of applications

Our inverter can output any imaginable output voltage, including DC voltage. Thanks to its software-defined functionality, we enable storage integrators to simplify their product portfolio and tap into different markets with the same hardware. In electric cars, it is even possible to charge the battery and operate the motor with the same power electronics.

AC und DC charging

Electric vehicles powertrain

Used in many countries



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