--- title: "FoxESS EP11 9.33 kWh Battery: Specs & Datasheet | ComparePV" description: "FoxESS EP11 9.33 kWh home battery. Specs: 95.0% round-trip efficiency, 4000 cycles, 99.0 kg, 10 yrs warranty." source: "https://comparepv.com/battery/fox-ess-ep11" updated: 2026-01-11 --- # FoxESS EP11 ## Identity - **Manufacturer:** FoxESS - **Model:** EP11 - **Series:** EP - **Usable energy:** 9.33 kWh - **Voltage class:** High voltage - **Cell technology:** LFP ## How it compares Compared against 44 batteries from 6 to 12 kWh. Ranks are within that class. | Measure | This battery | Class median | Standing | Rank in class | | --- | --- | --- | --- | --- | | Round-trip efficiency | 95.0% | 95.0% | Typical | 5 | | Power per kWh | - | 1.00 | | | | Cycle life | 4000 | 6000 | Weak - bottom 2% | 29 | | Weight per kWh | 10.6 | 12.3 | Typical | 11 | | Warranty | 10 yrs | 10 yrs | Typical | 3 | ## Specification ### Capacity - **Usable energy:** 9.33 kWh - **Nominal energy:** 10.36 kWh - **Depth of discharge:** 90 % - **Max system capacity:** 37.3 kWh - **Units in parallel:** 4 ### Power - **Max discharge current:** 27 A - **Max charge current:** 27 A - **Peak discharge current:** 65 A ### Efficiency and lifetime - **Round-trip efficiency:** 95.0 % - **Cycle life:** 4000 cycles ### Cells and voltage - **Voltage class:** High voltage - **Nominal voltage:** 384.0 V - **Operating voltage:** 348 to 438 V - **Cell technology:** LFP - **Cell management:** Cobalt-free ### Physical - **Dimensions:** 625 × 710 × 147 mm - **Weight:** 99.0 kg - **Enclosure:** IP65 - **Mounting:** wall - **Outdoor installation:** Yes - **Cooling:** passive - **Operating temperature:** -10 to 55 °C ### Compatibility - **Compatible inverters:** Fox ESS H1 series, Fox ESS KH series, Fox ESS H3 series, Fox ESS H3-Pro series, Fox ESS US series - **Protocols:** CAN ### Warranty and certificates - **Warranty:** 10 years - **Certifications:** IEC62619, EN IEC 61000-6-1/3, UN38.3 ### Pros - **6,000 cycles of LFP at 90% Depth of Discharge** - The official datasheets for EP11 and EP12 state ≥6,000 full cycles at a 90% depth of discharge, with a guaranteed capacity retention of ≥70% after 10 years. In comparison, standard NMC-class batteries typically guarantee 3,000-4,000 cycles at a lower DoD (80%), which translates to a significantly lower LCOS (cost of stored energy) over the entire lifespan of the system. - **IP65 rating and passive cooling** - The entire series of enclosures has achieved IP65 protection, allowing for installation outdoors without the need for additional enclosures. The absence of active cooling (fans) eliminates one of the most common failure points in ESS systems in warehouses and reduces maintenance costs throughout the system's lifespan. - **Scalable up to 46.08 kWh** - The EP6 (5.76 kWh) and EP12 PLUS (11.52 kWh) models can be connected in parallel in a configuration of up to 4 units, achieving 23.04 kWh or 46.08 kWh at a single connection point, respectively. This allows for phased system expansion without the need to replace the inverter or cabling, which is a significant cost advantage during upgrades. - **Integrated BMS in a single enclosure** - The BMS is integrated directly into the battery module housing (unlike solutions that require a separate, externally mounted controller). This simplifies communication wiring, reduces the number of installation components, and shortens startup time - which installers highlight as one of the practical advantages of this series. - **Round-trip efficiency ≥95%** - Datasheets for EP systems declare a power circuit efficiency of ≥95%. An independent study on the efficiency of battery systems, published in 2026 (IndexBox/Solar Performance Study), found that the FoxESS DC-coupled system achieved a System Performance Index of 97% - the best result in the 10 kW category, surpassing configurations from Kostal+BYD, among others. ### Cons - **A brief history of the brand (since 2019)** - FoxESS was founded in 2019, which means it has only been operating in the market for approximately 6 years at the time of offering a 10-year warranty. For comparison, BYD has been operating since 1995, and Sungrow since 1997. The company's relatively short operating history raises legitimate questions about its ability to provide long-term service and handle warranty claims - a crucial factor for institutional and bank-financed projects. - **Closed-loop inverter system** - The EP series communicates using the CAN protocol, optimized for FoxESS hybrid inverters (H1, KH, H3, H3-Pro). Compatibility with inverters from other manufacturers (e.g., SMA, Fronius, Growatt) is limited or not guaranteed by the manufacturer. In projects involving the modernization of existing installations using inverters from other brands, this may necessitate replacing the inverter or incur additional integration costs. ## About this series The FoxESS EP series are high-voltage energy storage solutions meticulously designed to significantly simplify the construction of domestic or commercial PV systems with self-consumption. Within a single housing, you receive an **integrated BMS** and the battery, facilitating configuration, monitoring, and safe operation in daily cycles. The applied chemistry, **LiFePO4 (LFP)**, stands out for its stable thermal properties and resilience to intensive operation, which translates to more reliable system performance, reduced overheating risks, and a longer lifespan compared to NMC solutions. The high cycle life and long-term warranty translate to a genuinely lower cost of stored energy over the entire service life, not just on paper. The EP series can conveniently be **expanded in parallel**, allowing the system to grow alongside the user's needs - from a single-family home, through a small business, up to more demanding scenarios with backup power. A key advantage is also its **compatibility with FoxESS hybrid inverters**, simplifying selection and minimizing integration issues in both new and retrofitted installations. ## Questions ### What is the warranty period for the FoxESS EP energy storage system, and what does it cover? FoxESS provides a 10-year warranty on the entire EP series, calculated from the date of installation (no more than 125 months from production). The warranty covers maintaining at least 70% of the nominal capacity throughout this period. This applies to both the EP5 and EP6 models, as well as the larger EP11 and EP12 models. This is one of the best capacity warranties available in this price range on the Polish market. ### How can I expand a system with a FoxESS EP battery when I need more capacity? The EP series allows for expansion by connecting up to four units in parallel. This means that starting with a 10.36 kWh EP11 model, you can ultimately achieve a total capacity of up to 40.8 kWh in a single installation. Expansion can be carried out over time without replacing the inverter - simply purchase an additional module and connect it to the existing system. ### Does the FoxESS EP battery function properly in low temperatures, such as in an unheated garage or outdoors? Yes, the EP series is certified with an IP65 degree of protection, which allows for installation outdoors. The operating range is from -10°C to 55°C. In temperatures below zero, the battery will operate, but its charging performance may be limited - therefore, for locations with very cold winters, it is advisable to install it in a technical room or garage with minimal heating. ### What distinguishes the LiFePO4 chemistry in FoxESS EP from older NMC batteries, and is this a significant factor when making a choice? LiFePO4 (LFP) is more thermally stable than NMC - the cells do not undergo self-ignition even under mechanical damage. The EP series achieves over 4,000 full cycles with efficiency above 95%, which, with daily charging, translates to over a decade of operation. NMC offers higher energy density, but at the cost of durability and safety, making LFP the industry standard for home energy storage. ### Which hybrid inverters does the FoxESS EP energy storage system work with? The EP series is natively compatible with FoxESS hybrid inverters, such as the H3, AIO, and ECS lines. Communication is achieved through the built-in BMS, eliminating the need for additional intermediary modules. If you are planning a new installation or upgrading an existing system with a FoxESS inverter, the selection process is straightforward and avoids the integration issues often associated with mixed systems from different brands. ### What is the minimum and maximum capacity available in the FoxESS EP series? The EP series begins with the EP5 model (5.18 kWh) and also includes the EP6 (6.14 kWh), EP11 (10.36 kWh), and EP12 (11.52 kWh) models. By connecting four units in parallel, the system can achieve a capacity of up to approximately 40 kWh. This makes the EP series suitable for both small single-family homes and commercial installations with higher energy storage needs. ## Datasheet [Manufacturer datasheet (PDF)](https://comparepv.com/datasheets/batteries/2fbec3dca67c788623af9dbf63f9e4c88954c048_Karta_Katalogowa-61891f0fe1be.pdf) ## Alternatives | Battery | Usable energy | Round-trip | Power | Voltage | Difference | | --- | --- | --- | --- | --- | --- | | [Solplanet Ai-HB 100A](https://comparepv.com/battery/solplanet-ai-hb-100a) | 9.21 kWh | 95.0% | 6.1 kW | HV | -0.1 kWh | | [FoxESS HS10](https://comparepv.com/battery/foxess-hs10) | 9.53 kWh | | | HV | +0.2 kWh | | [Pylontech Force H2 (3 modules)](https://comparepv.com/battery/pylontech-force-h2-3-modules) | 9.59 kWh | | | HV | +0.3 kWh | | [Pylontech Force H1 (4 modules)](https://comparepv.com/battery/pylontech-force-h1-4-modules) | 8.96 kWh | | | HV | -0.4 kWh | | [SMA Home Storage 9.8](https://comparepv.com/battery/sma-solar-technology-ag-sma-home-storage-9-8) | 9.84 kWh | 94.5% | 10.4 kW | HV | +0.5 kWh, -0.5 pp round-trip | | [Huawei LUNA2000-10-S0](https://comparepv.com/battery/huawei-luna2000-10-s0) | 10 kWh | | 5.0 kW | HV | +0.7 kWh | | [BYD Battery-Box Premium HVS 10.2](https://comparepv.com/battery/byd-battery-box-premium-hvs-10-2) | 10.24 kWh | 96.0% | 10.2 kW | HV | +0.9 kWh, +1.0 pp round-trip | | [FoxESS ECS2900-H4](https://comparepv.com/battery/fox-ess-ecs2900-h4) | 10.37 kWh | 95.0% | | HV | +1.0 kWh | --- Source: https://comparepv.com/battery/fox-ess-ep11