Fortress Power eFlex MAX 5.4kWh Lithium Battery Storage | 8,000+ Cycles | 99% Efficiency | Outdoor-Ready Design
Reliable Backup. Long-Term Value. Ultimate Flexibility.
The Fortress Power eFlex MAX delivers industry-leading performance and durability with 5.4kWh of usable energy, 8,000+ cycle life, and 99% round-trip efficiency. Built for residential and off-grid systems, this 48V LFP battery provides uninterrupted power with smart integration and easy installation.
Designed for indoor or outdoor use, the eFlex MAX combines rugged, weatherproof construction with scalable design, making it ideal for energy-conscious homeowners, remote cabins, or space-constrained installations.
Key Features
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Maximum Lifespan + Performance:
- 8,000+ charge cycles and 10+ year lifespan
- High-efficiency output with minimal degradation
- Patented aluminum shell for thermal stability and durability
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Rugged, Weatherproof Construction:
- IP65-rated aluminum enclosure
- Saltwater-resistant for indoor or outdoor use
- Ideal for basements, garages, backyards, boats, or RVs
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Ultra-Efficient Operation:
- Up to 99% round-trip efficiency
- Only 2W standby power consumption
- Optimized for solar self-consumption and off-grid use
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Effortless Scalability:
- Integrated busbars for parallel connection of multiple units
- Supports higher current loads for larger systems
- Simplifies installation and expansion
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Flexible, Code-Compliant Installation:
- Wall or floor mounting options
- Waterproof front cover for clean, quick, and compliant installs
- Minimal wiring and conduit required
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Smarter System Integration:
- Compatible with hybrid inverters and energy management systems
- Supports intelligent monitoring and load shifting
- Enables time-of-use optimization
Applications
- Residential energy storage
- Apartments and condos
- Off-grid cabins and homesteads
- RVs, boats, and marine systems
- Solar backup systems
What’s Included
- 1 × Fortress Power eFlex MAX 5.4kWh Battery
- 1 × Mounting Bracket Kit
- 1 × User Manual
- 1 × Warranty Registration Card
Note: The eFlex MAX 5.4kWh is not compatible with the standard eFlex 5.4kWh model.
Specification Sheets:
Fortress Power eFlex MAX 5.4kWh Lithium Battery Specifications (PDF)
Manuals:
Fortress Power eFlex MAX 5.4kWh Lithium Battery Installation Guide & Owner Manual (PDF)
Ingeration Guide:
Fortress Power eFlex MAX 5.4kWh Lithium Battery Integration Guide (PDF)
