Description
The Fortress Power eFlex MAX 5.4 is a premium Tier-1 automotive-grade lithium iron phosphate battery engineered to deliver world-class performance across the widest range of application scenarios and harsh weather conditions, combining industry-leading thermal management, a robust IP65 anodized aluminum enclosure, and a market-leading digital processor BMS in a single, versatile energy storage unit.
Key Features:
- Tier-1 Automotive Prismatic LFP Cell with 8,000-Cycle Life at 80% DoD: Built with the highest cycle-life prismatic lithium iron phosphate cells in the industry, delivering long-term reliability and consistent performance across thousands of charge and discharge cycles.
- Patented Anodized Aluminum Enclosure with 4x Better Thermal Performance: The eFlex MAX's patented enclosure design achieves four times better thermal performance than competing products, ensuring optimal battery health in extreme heat and cold environments.
- IP65 Dust and Waterproof Rating for Indoor and Outdoor Installations: Fully sealed against dust and water ingress, the eFlex MAX is built for confident installation in garages, basements, utility rooms, and fully exposed outdoor environments.
- Market-Leading Digital Processor BMS with CAN, Modbus, and OTA Updates: The integrated BMS features individual cell voltage and temperature monitoring, cell balancing, 125A integrated breaker, remote monitoring, and advanced closed-loop communication with most 48V inverters.
- Scalable Up to 86.4kWh — Up to 16 Units in Parallel: Start with a single 5.4kWh module and expand to a maximum of 16 units in parallel for a total system capacity of 86.4kWh without system redesign.
The Fortress Power eFlex MAX 5.4 sets a new benchmark for residential and light commercial lithium battery storage. Its patented enclosure design delivers thermal performance that no competitor in its class can match, while the Tier-1 automotive prismatic LFP cells ensure that every charge cycle is performed with maximum efficiency and minimum degradation over the life of the system.
With a minimal idle consumption of just 2W and an efficiency rating of over 98% at 0.5C, the eFlex MAX wastes virtually nothing. Its advanced digital processor BMS provides individual cell-level monitoring and balancing, ensuring every cell performs at its peak and the battery pack remains balanced throughout its entire service life. OTA firmware updates keep the BMS current without requiring a technician on site.
Note: Wall mount bracket and busbar are not included with this listing. Communication cables and eFlex MAX Top Cover are included.
Technical Specifications
| Specification | eFlex MAX 5.4 |
|---|---|
| ELECTRICAL | |
| Nominal Voltage | 51.2V |
| Nominal Capacity | 105 Ah |
| Rated Capacity @ 0.5C | 5.374 kWh |
| Resistance | <10 mΩ |
| Efficiency @ 0.5C | >98% |
| Self-Discharge | <1% per Month |
| Depth of Discharge | Up to 100% |
| Maximum Units in Parallel | 16 (86.4kWh) |
| CHARGE | |
| Recommended Charge Current | <55A |
| Maximum Charge Current | 100A |
| Recommended Charge Voltage | 54.4V |
| BMS Charge Voltage Disconnect | >56V |
| Bulk / Absorb Charge | 54.4V |
| Float Charge | 54V |
| Absorb Time | 60 Minutes |
| DISCHARGE | |
| Recommended Continuous Discharge | 60A (3kW DC) |
| Peak Continuous Discharge | 100A (5kW / 60 Min) |
| Maximum Surge Power Rate | 125A (6.6kW / 5s) |
| Recommended Low Voltage Disconnect | 48V |
| Battery Low Voltage Protection | <45V |
| Battery Recovery Voltage | 45V |
| Fault Current | 3000A, 5ms |
| TEMPERATURE | |
| Discharge Temperature | -4°F to 131°F (-20°C to 55°C) |
| Charge Temperature | 32°F to 114°F (0°C to 45°C) |
| Storage Temperature | 20°F to 95°F (-6°C to 35°C) |
| MECHANICAL | |
| Dimensions (L x W x H) | 17.5 x 7.2 x 24.2 in |
| Weight | 108 lbs |
| Case Material | Anodized Aluminum |
| Enclosure Protection | IP65 |
| Cell Type | Tier-1 Automotive Prismatic LiFePO4 |
| Terminal Type | M8 |
| Ring Terminal Size | 3/8 in or Larger |
| Terminal Torque | 7.0–7.7 Nm (5.1–5.7 ft-lb) |
| Terminal Cover | 1 Set, Waterproof |
| Mounting Options | Floor-Stand, 19-in Server Rack (Wall Mount Sold Separately) |
| BMS | |
| Integrated Breaker | 125A |
| Cell Monitoring | Individual Voltage and Temperature |
| Communication | CAN Bus / Modbus / OTA Firmware |
| Idle Consumption | 2W |
| INCLUDED IN BOX | |
| Communication Cables | Included |
| eFlex MAX Top Cover | Included |
| Wall Mount Bracket | Not Included |
| Busbar | Not Included |
Specs & Info