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Dr. Eric Rüland ist neuer Geschäftsführer der RCT Power GmbH


Again a double victory: The power storage systems from RCT Power rank first in both performance classes

HTW Berlin - Energy Storage Inspection 2024

The outstanding energy efficiency of RCT Power's power storage systems was once again confirmed in 2024. As the previous year, they ranked top in the 5 kW and 10 kW performance classes in the annual Energy Storage Inspection by HTW Berlin (University of Applied Sciences). The 2024 edition of the Inspection included a new feature: The test team examined the energy efficiency of selected storage systems at low discharge capacities. The RCT Power system showed excellent results in this test category.


Highest efficiency class A

In the 2024 edition of their annual Energy Storage Inspection, the test team of HTW Berlin assessed twenty solar energy storage systems from fourteen different manufacturers. A few years ago, the team at HTW Berlin developed a methodology to evaluate storage systems based on the energy flows at the grid connection point and attaching monetary values to energy withdrawn or fed into the grid. The inverter efficiency in the energy conversion pathway, the standby consumption, the response time and the control accuracy all influence the overall energy flow. The operational behaviour of each tested system is then simulated over one year to obtain the 'System Performance Index' (SPI) that allows for a fair comparison of the storage systems. The participating storage systems are grouped based on their size into two categories, SPI (5 kW) and SPI (10 kW), as larger systems are generally more efficient.


The SPI results in the Energy Storage Inspection 2024 for RCT Power:

  • RCT Power Storage DC 10.0 and Power Battery 11.5: 96.4 %
  • RCT Power Storage DC 6.0 and Power Battery 7.6: 92.6 %


RCT Power is characterized by maximum efficiency. The average annual loss of self-generated solar power is only 3.6 percent. This means that 96.4 percent goes into the socket and can be used. With a desired output of 200 watts, 17 watts are lost through conversion. With the less efficient inverter, the conversion losses of 82 W are 4 times higher.



Source: HTW Berlin


High performance at partial load discharging

In this year's inspection, the test team examined the inverter discharge efficiency at partial loads for the first time. The output power range of 100 to 300 Watts is of interest to house owners. Analysis by HTW Berlin's team of 28 selected detached houses shows that the majority have night-time power consumption in this range. It is, therefore, beneficial if the inverter has an excellent discharge efficiency in this partial load range.

The hybrid inverter Power Storage DC 10.0 from RCT Power performs outstanding. At a presumed power output of 200 watts, it has a discharge efficiency of 92 per cent, which rises to over 98 per cent at higher output values. It means the inverter loses only 17 watts through conversion at 200 watts of output power. By comparison, the device with the lowest efficiency only has a discharge efficiency of 71 per cent under the same conditions and will lose 82 watts through conversion.


Annual savings of 182 euros due to high-efficiency

The simulation-based system evaluation with the SPI can determine the financial impact of the efficiency losses of the tested systems. Storage systems with higher efficiency rates will realise greater annual energy cost savings - assuming the identical structural and energy demand requirements. Using the determined storage system SPI, the test team calculated that the high efficiency of the RCT Power systems would save the user an additional 182 euros compared to the system at the bottom of the ranking table.


More power than stated in the datasheet

The test team examined the usable storage capacity in a laboratory test and compared the results with the listed values in the manufacturer's datasheets. The measured usable storage capacity of RCT Power's power storage systems was two per cent higher than stated in the data sheet. The user, therefore, gets more than promised. RCT Power was also a laudable exception. The results for the majority of the tested storage systems showed lower values than quoted in the datasheets. For one, the deviation was 11 per cent.


Technology leadership in an expanding market

The photovoltaic and battery storage markets continue to grow strongly. Last year, new PV systems were installed on approximately four per cent of German detached and duplex houses. In the same period, 530'000 new residential battery storage systems were added, an increase of 153 per cent compared to 2022. The excellent energy efficiency of RCT Power's storage systems translates into reduced losses during charging and discharging. They, therefore, use the stored energy more effectively. They increase the degree of self-sufficiency and thus contribute to the security of supply.

The renewed top positions in the annual Energy Storage Inspection illustrate and prove the ongoing technological leadership RCT Power has pursued since its foundation.



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