Fortress Power eFlex Max 5.4kWh 48V LFP Battery - Modular Storage
Battery bank buying guide · 48V vs high-voltage architecture · Request a quote
PayPal Pay in 4 interest-free payments of $379.75 on qualifying orders, or monthly financing with PayPal Pay Later.
Available at checkout for eligible US buyers. Subject to approval.
Ships by freight. Carrier checkout rates can’t price this correctly — we quote the exact delivered rate to your ZIP.
Orders ship via freight or ground from our Louisville, KY warehouse. Tracking provided once your order ships.
Ships via LTL freight — palletized, liftgate available. Our team confirms freight details within 1 business day.
✓ Lock pricing 7 days · Share with clients · Wire/ACH accepted
Secure checkout · Wire/ACH accepted on quotes · Freight arranged for you
Transit estimates from Louisville, KY. Freight details →
- SKU
- FP-EFLEXMAX54
- Unit price
- $281/kWh
Complete the job
Compatible gear contractors pair with this item
PES Supply is an authorized distributor for Fortress Power. 50,000+ SKUs from 169 authorized brands.
Fortress Power eFlex Max — 5.4kWh 48V LFP Battery | Modular
The Fortress Power eFlex Max is a 5.4kWh lithium iron phosphate (LFP) battery module designed for residential and commercial energy storage. Built with premium LFP cells and an intelligent BMS, the eFlex Max delivers 6,000+ cycles of reliable performance. Its modular design allows stacking up to 6 batteries for 32.4kWh of total capacity, and it communicates seamlessly with leading 48V inverters via CAN/RS485.
Key Benefits
- 5.4kWh Modular Capacity — Stack up to 6 batteries for 32.4kWh of scalable storage
- LiFePO4 Chemistry — Inherently safe lithium iron phosphate with superior thermal stability
- 6,000+ Cycle Life — Decades of daily cycling with minimal capacity degradation
- Intelligent BMS — Built-in battery management system with active cell balancing
- Plug-and-Play Installation — Simple parallel connection — no complex programming required
- Wide Inverter Compatibility — CAN/RS485 communication with leading 48V hybrid inverters
- Indoor & Outdoor Rated — Flexible installation in protected environments
Specifications
| Specification | Detail |
|---|---|
| Usable Capacity | 5.4 kWh |
| Nominal Voltage | 51.2V DC |
| Nominal Capacity | 105Ah |
| Battery Chemistry | Lithium Iron Phosphate (LFP) |
| Cycle Life | 6,000+ cycles |
| Charge/Discharge Current | 50A / 100A peak |
| Scalable | Up to 6 units (32.4kWh) |
| Communication | CAN / RS485 |
| Operating Temperature | -4°F to 122°F (-20°C to 50°C) |
| Dimensions | 18.5 × 7.5 × 19.7 in (approx.) |
| Weight | ~110 lbs (50 kg) |
| Warranty | 10 years |
What's in the Box
- Fortress Power eFlex Max 5.4kWh Battery
- Communication cable
- Parallel connection cable
- User manual
| SKU | FP-EFLEXMAX54 |
|---|---|
| Manufacturer | Fortress Power |
| Container price | |
| Container qty | |
| Datasheet |  |
| Pallet price | |
| Pallet qty | |
| Unit price |
