--- title: "Dyness Tower T21 21.31 kWh Battery: Specs & Datasheet | ComparePV" description: "Dyness Tower T21 21.31 kWh home battery. Specs: 12.8 kW continuous, 6000 cycles, 269.0 kg, 10 yrs warranty." source: "https://comparepv.com/battery/dyness-tower-t21" updated: 2026-01-11 --- # Dyness Tower T21 ## Identity - **Manufacturer:** Dyness - **Model:** Tower T21 - **Series:** Tower - **Usable energy:** 21.31 kWh - **Voltage class:** High voltage ## How it compares Compared against 29 batteries from 20 to 50 kWh. Ranks are within that class. | Measure | This battery | Class median | Standing | Rank in class | | --- | --- | --- | --- | --- | | Round-trip efficiency | - | 95.0% | | | | Power per kWh | 0.60 | 0.51 | Typical | 5 | | Cycle life | 6000 | 6000 | Typical | 2 | | Weight per kWh | 12.6 | 11.1 | Weak - bottom 16% | 24 | | Warranty | 10 yrs | 10 yrs | Typical | 2 | ## Specification ### Capacity - **Usable energy:** 21.31 kWh - **Nominal energy:** 21.31 kWh - **Depth of discharge:** 100 % - **Modules per stack:** 2 to 6 ### Power - **Continuous discharge power:** 12.78 kW - **Continuous charge power:** 12.78 kW ### Efficiency and lifetime - **Cycle life:** 6000 cycles ### Cells and voltage - **Voltage class:** High voltage - **Nominal voltage:** 576.0 V ### Physical - **Dimensions:** 1500 × 504 × 380 mm - **Weight:** 269.0 kg - **Enclosure:** IP54 - **Mounting:** floor - **Operating temperature:** -10 to 50 °C ### Compatibility - **Compatible inverters:** Goodwe, Solis, Hoymiles, Sermatec, A1TES, Sigenxcell, Luxpower, Sunways, (and more—stated as many brands; exact list not fully legible) - **Protocols:** Modbus ### Warranty and certificates - **Warranty:** 10 years - **Certifications:** TUV, CE, IEC 62619, UN38.3, CEC Accredited, UL 1973 ### Pros - **LFP + 95% DoD = >6,000 guaranteed cycles** - The chemistry of LiFePO4 guarantees ≥6,000 full cycles with a 95% depth of discharge and a minimum 70% state of health (SoH) - this translates to over 16 years of use with a single charge per day. Competitive NMC systems (such as older generations of Sonnen) typically offer 10,000 cycles, but with an 80% depth of discharge, which results in a significantly smaller daily available capacity. - **10-year manufacturer's warranty** - The Dyness Tower is covered by a 10-year system warranty (≥6,000 cycles or 10 years, whichever occurs first) with a 70% SoH threshold. The warranty is valid globally, with specific documentation for the EU, AU, and NA markets - which is standard for leading ESS manufacturers, but distinguishes Dyness from many second-tier Asian brands. - **Compatibility with over 30 inverter brands** - The official Dyness Tower compatibility list (updated May 2025) includes over 30 hybrid inverter brands, including GoodWe, KOSTAL, Solis, DEYE, SAJ, Huawei, Fronius, and Solplanet. The list's breadth is comparable to that of BYD HVS and Pylontech HV, making the series independent of a single vendor's ecosystem. - **Modular scalability from 7.1 to 21.3 kWh** - The series includes 5 variants (T7-T21) with usable capacities ranging from 7.10 kWh to 21.31 kWh, as well as the ability to connect multiple units in parallel with capacities exceeding 21 kWh. Stackable mounting without wiring between modules reduces installation time to approximately 15 minutes - a significant logistical advantage compared to systems that require separate wiring for the rails. - **SPI reached 94.2% in the independent audit conducted in 2024.** - Tower T14 achieved a System Performance Index (SPI) of 94.2% in the official 2024 energy efficiency report. This is an independently verified result, not just a claim by the manufacturer - which is important when evaluating the Levelized Cost of Energy (LCOE) of the installation. ### Cons - **Brief overview of the producer's track record (since 2017)** - Founded in 2017, Dyness has only ~8 years of operational history compared to companies like Pylontech (2009), BYD Energy (2011), or CATL (2011). With a 10-year system warranty, a shorter market presence implies less certainty regarding the long-term availability of service and spare parts - a significant consideration when choosing an ESS for installations with a 15-20-year lifespan. - **Assessment of Class B efficiency, not Class A.** - Despite a SPI of 94.2%, Tower T14 achieved a B (not A) efficiency rating in the 2024 report. This means that the highest A-class threshold was not met - it's worth comparing with BYD HVS and SENEC systems, which achieve an A rating in similar tests, especially in applications requiring maximum cycle efficiency. ## About this series High-voltage, modular energy storage units designed to be assembled like building blocks - offering simple expansion without unnecessary complexity. The greatest advantage lies in the **LiFePO4 (LFP)** chemistry, providing high thermal stability and reliable operation for years - a practical choice where safety, consistent performance, and reduced degradation risk matter, unlike many NMC systems. In daily use, this translates to **a long lifespan measured in thousands of cycles** and **a multi-year warranty guarantee**, genuinely reducing energy costs throughout the entire service life. Dyness Tower also features **scalability** - you can start with a smaller configuration and gradually add modules, adapting the capacity to growing energy consumption or larger PV systems. The series is broadly **compatible with hybrid inverters** from various brands, making it suitable for new installations and retrofits. This solution is ideal for homes, businesses, and off-grid or backup power systems. ## Questions ### How many charge/discharge cycles can the Dyness Tower energy storage system handle, and how long will it last? The Dyness Tower Pro guarantees at least 8000 charging and discharging cycles, which, with daily use, translates to over 20 years of operation. Older models in the Tower series offer a minimum of 3000 cycles with a 10-year warranty. Thanks to the LiFePO4 chemistry, the degradation of the cells is significantly slower than in NMC systems, so the capacity remains at a high level throughout the specified operating life. ### What is the maximum capacity that can be achieved in the Dyness Tower Pro series? The Tower Pro series allows for the configuration of 2 to 6 modules, each with a capacity of 3.84 kWh, resulting in a total capacity of up to 23.04 kWh (approximately 21.9 kWh available with a 95% Depth of Discharge). Tower 2.0 models are available in T10 (10.66 kWh) and T14 (14.21 kWh) versions. The modular architecture allows for future expansion - you can purchase additional modules without replacing the entire system. ### What is the warranty for the Dyness Tower Pro series? Tower Pro offers a warranty of up to 15 years after product registration, or a standard 10-year warranty without registration. The warranty covers the capacity of the batteries and the functionality of the BMS electronics. Older models in the Tower series (T10, T14) are covered by a 10-year or 3000-cycle warranty. This is one of the longer warranties available in this price range on the Polish market. ### Which hybrid inverters does Dyness Tower work with? The Dyness Tower is a high-voltage (HV) system that communicates using CAN and RS485 protocols. It has been confirmed to be compatible with GoodWe (ET/EH series), Solis, Deye, Growatt, Kostal, Hoymiles, and Sunways inverters. Before purchasing, it is advisable to check the latest compatibility list from Dyness, as support for specific inverter models may depend on the firmware versions of both devices. ### Can the Dyness Tower be installed in an unheated garage or outdoors? The Dyness Tower has an IP55 rating, which means it is protected against dust and water jets - making it suitable for installation in sheltered outdoor locations or in a garage. The declared operating temperature range is from -20°C to +55°C. At very low temperatures, the BMS may limit the charging current, so for optimal performance, a surrounding temperature above 0°C is recommended. ### What differentiates the Dyness Tower Pro from the standard Dyness Tower 2.0 (T10/T14)? Tower Pro represents a new generation with increased lifespan (at least 8000 cycles compared to 3000 in Tower 2.0) and a longer warranty (up to 15 years). Tower Pro modules offer continuous power at a level of 1C, meaning a 11.52 kWh storage system can deliver and absorb 11.52 kW of power. For new installations, Tower Pro is clearly the better choice due to its longer return on investment. ## Datasheet [Manufacturer datasheet (PDF)](https://comparepv.com/datasheets/batteries/3db1a1525aadd1f547038a05.pdf) ## Alternatives | Battery | Usable energy | Round-trip | Power | Voltage | Difference | | --- | --- | --- | --- | --- | --- | | [Dyness Tower Pro TP23](https://comparepv.com/battery/dyness-tower-pro-tp23) | 21.89 kWh | 95.0% | 23.0 kW | HV | +0.6 kWh, +10.3 kW | | [Huawei LUNA2000-21-S1](https://comparepv.com/battery/huawei-luna2000-21-s1) | 20.7 kWh | | 10.5 kW | HV | -0.6 kWh, -2.3 kW | | [BYD Battery-Box Premium HVM 22.1](https://comparepv.com/battery/byd-battery-box-premium-hvm-22-1) | 22.08 kWh | 96.0% | | HV | +0.8 kWh | | [Deye GB-L24](https://comparepv.com/battery/gb-l24) | 22.08 kWh | | | HV | +0.8 kWh | | [Deye GB-SL-EU (6 modules in series)](https://comparepv.com/battery/gb-sl-eu-6-modules-in-series) | 22.08 kWh | | | HV | +0.8 kWh | | [Deye GB-L (6 modules in series)](https://comparepv.com/battery/ningbo-deye-ess-technology-co-ltd-gb-l-6-modules-in-series) | 22.1 kWh | | 24.6 kW | HV | +0.8 kWh, +11.8 kW | | [Pylontech Force H1 (FH48074)](https://comparepv.com/battery/pylontech-force-h1-fh48074) | 22.37 kWh | | | HV | +1.1 kWh | | [FoxESS ECS4300H-H6](https://comparepv.com/battery/fox-ess-ecs4300h-h6) | 22.39 kWh | 95.0% | | HV | +1.1 kWh | --- Source: https://comparepv.com/battery/dyness-tower-t21