eFlex MAX 5.4kWh | Smarter, Stronger, More Connected Energy Storage
A compact 48V LFP battery with closed-loop inverter integration, advanced communications, and installer-friendly design — ideal for scalable residential systems.
eFlex MAX 5.4kWh
Lithium Battery Storage
The eFlex MAX 5.4 kWh is a high-performance 48V lithium iron phosphate (LFP) battery engineered for maximum flexibility, reliability, and long-term energy savings. Designed to operate in demanding environments — from homes and apartments to off-grid cabins, RVs, and boats — it delivers uninterrupted backup power with smart inverter integration and advanced system communications.
With a guaranteed 8,000+ cycle life, a 10-year warranty, and built-in safety protections, the eFlex MAX meets the highest standards for quality and performance. Whether used for solar self-consumption, backup power, or off-grid storage, it’s a versatile solution built to last.
*The eFlex MAX 5.4kWh and the eFlex 5.4kWh LFP Battery are NOT compatible with each other.
Applications
Residential
Apartments and Condos
Off-Grid
Marine
FEATURES
PRODUCT INFORMATION
| 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% |
| Part | Description | Qty |
| 1 | eFlex MAX 5.4kWh | 1 |
| 2 | Manual | 1 |
| 3 | Battery-Inverter COMM Cable (9.9 ft.) | 2 |
| 4 | Top eFlex MAX Cover | 1 |
| 5 | IP65 Battery-Inverter Comm Cable (9.8ft.) | 1 |
| A | M4 * 8 Stainless Steel Cross Recessed Countersunk Head Screw | 2 |
| C | M8 * 16 Combination Cross Groove Recessed Hexagonal Head Bolt | 4 |
| Part | Description | Qty |
| 1 | Busbar (300A) | 1 Pair |
| 2 | 1¼ -Inch Threaded Conduit Fitting | 1 |
| 3 | Back Support | 1 |
| 4 | Wall Mount Bracket | 1 Pair |
| 5 | Busbar Bottom Cover | 1 |
| 6 | Busbar Top Cover | 1 |
| 7 | Wall Mount template | 1 |
| B | M4 * 6 Stainless Steel Cross Pan Head Screw | 5+1 |
| D | M4*25 Hexagonal Socket Head Cap Screw | 3 |
| E | M6 * 20 European Standard 30, T-bolt & M6 Flange Nut | 6+1 extra |
| F | M8*60 Expansion Screw | 2 |
| G | M6*50 Wood Screw | 2 |
VIDEO LIBRARY
eFlex MAX 5.4kWh Video Library
0:51
7:05
2:18
36:39
PRODUCT COMPATIBILITY
Fortress Power Envy Inverters
Two Apps. One Powerful Energy Ecosystem.
The Fortress Power Owner and Pro apps give homeowners and installers the right tools to monitor, manage, and support Fortress Power systems, anytime, anywhere.
