Fortress eFlex 5.4 kWh Lithium Ferro Phosphate LFP Battery
Fortress eFlex 5.4 kWh Lithium Ferro Phosphate LFP Battery
Fortress eFlex 5.4 kWh Lithium Ferro Phosphate LFP Battery
Fortress eFlex 5.4 kWh Lithium Ferro Phosphate LFP Battery
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Fortress eFlex 5.4 kWh Lithium Ferro Phosphate LFP Battery
eFLEX 5.4
PLEASE NOTE, THIS PRODUCT HAS SLIGHTLY EXTENDED LEAD TIMES DIFFERENT FROM OUR STANDARD. EXPECT THIS PRODUCT TO SHIP IN 10-14 BUSINESS DAYS
Fortress eFlex 5.4 kWh Lithium Ferro Phosphate LFP Battery
Key Benefits
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Provides 5.4kWh of high-efficiency energy storage with >98% round-trip efficiency
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Compact, wall-mountable, or rack-mountable design for flexible installation
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Long cycle life with 8,000 cycles at 80% depth of discharge
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Built-in BMS ensures battery protection and performance in real time
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IP65-rated enclosure for outdoor or indoor use in harsh weather conditions
Special Technology
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Tier 1 automotive-grade prismatic LiFePO4 cells for maximum reliability
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Advanced digital BMS with contactor disconnects and individual cell balancing
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Supports Canbus, Modbus, and Wi-Fi communication protocols for inverter integration
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Compatible with major inverter brands including Sol-Ark, SMA, Schneider, Victron, Growatt, and more
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Patented aluminum enclosure with 4x improved thermal performance compared to competitors
Warranty
Fortress Power offers a 10-year warranty on the eFlex 5.4 lithium battery, with an expected cycle life of 8,000 cycles at 80% DoD, ensuring long-term value and peace of mind.
Best Use
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Ideal for residential backup and whole-home energy storage
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Perfect for off-grid cabins, zero-export systems, and demand response programs
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Suitable for grid-tied PV systems with AC or DC coupling
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Designed for environments requiring NEMA 3R/IP65 outdoor-rated enclosures
Specifications Table
| Attribute | Specification |
|---|---|
| Product Name | Fortress Power eFlex 5.4 |
| Usable Capacity | 5.374 kWh |
| Nominal Voltage | 51.2V |
| Nominal Capacity | 105Ah |
| Round-Trip Efficiency | >98% |
| Depth of Discharge | Up to 100% |
| Cycle Life | 8,000 cycles at 80% DoD |
| Continuous Discharge | 60A (3kW DC) |
| Peak Discharge (60 min) | 100A (5kW) |
| Surge Discharge (5 sec) | 130A (6.6kW) |
| Charge Voltage | 54.4V |
| Charge Current (Recommended) | <55A (Max 100A) |
| Enclosure Rating | IP65 / NEMA 3R |
| Dimensions (L × W × H) | 21.5 × 17.5 × 7.2 inches |
| Weight | 108 lbs |
| Certifications | UL9540, UL1973, UL1642, UL9540A, UN38.3 |
| Operating Temp Range | -4°F to 131°F (Discharge) |
| Mounting Options | Wall Mount, Floor Stand, 19” Rack |
| Warranty | 10 Years |
About Fortress Power
Fortress Power is a U.S.-based energy storage manufacturer committed to delivering advanced lithium battery systems for homes, businesses, and utilities. With a focus on safety, reliability, and innovation, Fortress Power’s products are engineered for superior thermal management, ease of installation, and compatibility with leading inverters. Their batteries meet UL9540 and UL1973 standards and are designed to perform in diverse climates and use cases. Fortress Power empowers customers to achieve energy independence with clean, efficient, and intelligent battery solutions.
Why Buy From US Solar Supplier?
As an American founded company out of Kentucky, US Solar Supplier is committed to providing top-quality solar products, backed by the world’s leading manufacturers. Our promise is to get you the fairest price from the best brands that offer warranties you can count on. We are updating our inventory daily with solar components that offer the latest technology. With a reputation for excellence and a dedication to customer satisfaction, we ensure that every product we sell meets the highest standards in the industry.
Need Assistance?
We’re here to help! If you have any questions or need more information before making your purchase, don’t hesitate to call us at 1-800-230-7004. Our knowledgeable and friendly team is ready to assist you with product details, installation advice, or the purchasing process.
Why Buy From Us?
Trusted Supplier: We work with Tier 1 manufacturers who stand behind their products.
Expert Support: Our team is here to guide you every step of the way.
Manufacturer-Backed Warranties: Fortress Power offers a 10-year warranty on the eFlex 5.4 lithium battery, with an expected cycle life of 8,000 cycles at 80% DoD, ensuring long-term value and peace of mind.
Easy and Secure Checkout: Your information is protected with top-notch security for a smooth, worry-free transaction.
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