Fortress eFlex 5.4 kWh Lithium Ferro Phosphate LFP Battery
MPN No: eFLEX 5.4
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Out Of Stock
$2,999.00
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MPN No: eFLEX 5.4
Contact us for Delivery Date
Out Of Stock
$2,999.00
PLEASE NOTE, THIS PRODUCT HAS SLIGHTLY EXTENDED LEAD TIMES DIFFERENT FROM OUR STANDARD. EXPECT THIS PRODUCT TO SHIP IN 10-14 BUSINESS DAYS
Provides 5.4kWh of high-efficiency energy storage with >98% round-trip efficiency
Compact, wall-mountable, or rack-mountable design for flexible installation
Long cycle life with 8,000 cycles at 80% depth of discharge
Built-in BMS ensures battery protection and performance in real time
IP65-rated enclosure for outdoor or indoor use in harsh weather conditions
Tier 1 automotive-grade prismatic LiFePO4 cells for maximum reliability
Advanced digital BMS with contactor disconnects and individual cell balancing
Supports Canbus, Modbus, and Wi-Fi communication protocols for inverter integration
Compatible with major inverter brands including Sol-Ark, SMA, Schneider, Victron, Growatt, and more
Patented aluminum enclosure with 4x improved thermal performance compared to competitors
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.
Ideal for residential backup and whole-home energy storage
Perfect for off-grid cabins, zero-export systems, and demand response programs
Suitable for grid-tied PV systems with AC or DC coupling
Designed for environments requiring NEMA 3R/IP65 outdoor-rated enclosures
| 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 |
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.
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.
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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.
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