Fortress Power | eFlex Max 5.4 kWh LFP Battery
eFlex MAX 5.4 kWh LFP Battery – High-Performance Lithium Storage with Maximum Longevity
The eFlex MAX 5.4 kWh LFP Battery delivers exceptional energy storage with premium performance, safety, and flexibility. Engineered for residential, commercial, off-grid, and marine use, this next-generation lithium iron phosphate (LiFePO4) battery offers 8000+ cycles and 99% round-trip efficiency, all within a durable, saltwater-resistant aluminum enclosure. It's the ideal choice for anyone seeking long-lasting power and smart scalability.
Key Features:
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8000+ Cycles, 10-Year Warranty – Built to last over a decade with consistent deep-cycle performance.
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Premium Aluminum Enclosure – Patented ¾″ saltwater-resistant casing ensures rugged durability for indoor or outdoor installation.
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Industry-Leading Thermal Management – Up to 3X better thermal regulation than competitors for improved safety and lifespan.
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99% Efficiency & 2W Idle Power – Minimizes standby power loss, saving more energy in off-grid and backup systems.
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Seamless Scalability – Built-in busbars support parallel connections of multiple units, enabling higher capacity and fewer installation errors.
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Flexible Mounting Options – Install on walls or floors with included waterproof front panel, no external conduit required.
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Versatile Applications – Perfect for homes, condos, off-grid cabins, RVs, boats, and solar energy systems.
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Best-in-Class Value – Combining top-tier performance, long life, and affordability for the best total cost of ownership in its class.
What's Included
| Part | Description | Qty |
| 1 | eFlex MAX 5.4kWh | 1 |
| 2 | 1¼ -Inch Threaded Conduit Fitting | 1 |
| 3 | Busbar Top Cover | 1 |
| 4 | Top eFlex MAX Cover | 1 |
| 5 | Wall Mount Bracket | 1 Pair |
| 6 | Manual | 1 |
| 7 | Busbar (300A) | 1 Pair |
| 8 | Busbar Bottom Cover | 1 |
| 9 | Wall Mount template | 1 |
| 10 | Floor Mount Bracket | 1 Pair |
| 11 | Back Support | 1 |
| 12 | 2-Way RJ45 Splitter | 1 |
| 13 | ENVY & Sol-Ark Battery-Inverter COMM Cable (2 ft.) | 2 |
| 14 | IP65 Battery-Inverter Comm Cable (9.8ft.) | 1 |
| 15 | IP65 Battery-Battery Comm Cable (1.15ft.) | 1 |
| A | M4 * 8 Stainless Steel Cross Recessed Countersunk Head Screw | 2 |
| B | M4 * 6 Stainless Steel Cross Pan Head Screw | 5+1 |
| C | M8 * 16 Combination Cross Groove Recessed Hexagonal Head Bolt | 4 |
| D | M4*25 Hexagonal Socket Head Cap Screw | 3 |
| E | M6 * 20 European Standard 30, T-bolt & M6 Flange Nut | 6+1extra |
| f | M8*60 Expansion Screw | 4 |
| G | M6*50 Wood Screw | 4 |
Specification
| General | |
| Name | eFlex MAX 5.4 |
| Total Energy(kWh) | 5.4 |
| Max. Charge Current (Continuous) [A] | 100 |
| Max. Discharge Current (Continuous) [A] | 100 |
| Nominal Capacity [Ah] | 105 |
| Voltage Range [V] | 48-55 |
| Charging Temperature [F] | 32 ~ 114 |
| Discharging Temperature [F] | -4 ~ 131 |
| Storage Temperature [F] | 20 ~ 95 |
| Dimension [L x W x H, inch] | 17.5 x 24.2 x 7.2 |
| Weight [lbs] | 108 |
| Life Cycles | 8000 @ 80% DoD |
| Round Trip Efficiency | >98% |
Manuals and Downloads
eFlex MAX Owner / Installation Manual
Certification
Are Solar Guys Pro Authorized Retailers?
Yes! We are proud to be one of the few online retailers who are authorized retailers for every single product we carry!
When Will My Order Ship?
Most orders ship within 1–3 business days. You’ll get a tracking number as soon as it ships via email!
Do We Accept Returns?
Yes absolutely, we have a no-hassle, 30-day return policy on all items! To refer to the full policy, click HERE
Are Products Brand New?
Yes! All products on Solar Guys Pro are 100% brand-new and in perfect condition.
We do not sell any used or refurbished items.
Orders over $500 include a FREE (Normally $149.99) 80-Page DIY Solar eBook — added automatically at checkout.
Frequently Asked Questions
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