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
The eFlex MAX is easy to pair with your favorite third-party inverters with a simple click.
Monitor and control your eFlex MAX 5.4kWh. Anywhere! Anytime!
✅ Monitor Performance of Each Battery
✅ Update Firmware Over The Air
✅ Participate in Virtual Power Plant Programs
