The Fortress Power DuraRack is a weather-resistant, scalable battery enclosure designed to house and protect your eFlex 5.4kWh lithium batteries. Built with IP65-rated materials for indoor or outdoor installations, the DuraRack offers secure, professional-grade battery storage—whether you're expanding residential capacity or designing a robust commercial system.
Each DuraRack holds up to 4 eFlex batteries, and the system can be expanded up to 4 total enclosures, delivering a combined storage capacity of up to 81kWh. Pre-wired with integrated busbars and battery cables, and compatible with Fortress Power’s optional Heat Mat Kit, DuraRack is optimized for performance and durability in both hot and cold climates.
Key Features:
Indoor/Outdoor Ready Protection: With a durable steel housing and IP65 rating, the DuraRack is ideal for indoor utility closets or outdoor installations exposed to rain, dust, or snow.
Integrated Busbars & Pre-Wired Cabling:No need to source or install additional components. DuraRack comes ready with built-in busbars and battery cables, streamlining installation and ensuring a clean, code-compliant setup.
Cold Weather Compatible: Pair the DuraRack with an optional DIN rail-mounted Heat Mat Kit to keep your batteries within operating temperature in freezing environments—essential for northern climates or off-grid locations.
Passive Cooling for Warm Environments: Engineered with vented airflow, the enclosure promotes passive cooling, helping maintain optimal battery temperature and longevity in warmer climates.
Scalable System Architecture: Each enclosure supports up to 4 × eFlex 5.4kWh batteries, and you can scale up to 15 batteries across 4 DuraRacks, offering up to 81kWh of total energy storage.
Secure, Professional Appearance: With a tamper-resistant enclosure, clean design lines, and a low-profile footprint, the DuraRack delivers both security and curb appeal for residential and commercial sites.
Flexible Mounting Options: Install as a freestanding cabinet or pad-mounted unit, depending on your layout and space requirements.
Applications:
Residential Energy Storage
Light Commercial & Industrial Systems
Indoor Utility Rooms or Closets
Outdoor Patio or Wall-Mounted Installations
Off-Grid Projects in Harsh Climates
What’s Included:
1 × Fortress Power DuraRack Enclosure
Pre-installed busbars and battery interconnect cables
Mounting hardware and side knockouts for AC/DC wiring
DIN Rail for optional heater (Heat Mat Kit sold separately)
User Guide
Holds up to 4 Fortress Power eFlex 5.4kWh batteries per enclosure. Expand up to 4 units for a maximum of 15 batteries.
Specifications
DuraRack Specifications
Enclosure Material
Carbon Steel
Enclosure Protection
IP65 water and dust proven (outdoor)
Enclosure Color
White
Dimensions [W x H x D]
29.29 x 41.34 x 18.03 in (744 x 1050 x 458 mm)
Enclosure Weight
59.6 kg / 153.2 lbs
Maximum Battery Units
4 eFlex 5.4
Storage Capacity Range
5.4kWh – 21.6 kWh per unit
Max. Storage Capacity
81 kWh (4 unites in parallel)
Knockout Size
1 inch & 2 inch
Positive and Negative Battery Busbars
2 x 4 points; M8 (5/16) Terminal Rings
Positive and Negative Busbars to Inveter
2 points; m10 (3/8) Terminal Rings
Battery Cables
4 sets of
Terminal Torque
7.0 – 7.7 Nm (5.1 – 5.7 ft-lb)
Enclosure Warranty
3 Years
Certifications
UL9540, UL9540A, UL1973, CEC, SGIP
Shopping Guide
Power Storage & Inverter
Item / Appliance
Typical Power (W)
Usage Time (hrs)
Total Energy Needed (Wh)
Battery Size Needed (Ah) (12V System)
Inverter Size Needed (W)
LED Light Bulb (10W)
10W
5 hrs
50 Wh
4.2 Ah
100W
Phone Charging
5–10W
2 hrs
10–20 Wh
0.8–1.7 Ah
100W
Laptop Charging
50–100W
3 hrs
150–300 Wh
12.5–25 Ah
200W
Ceiling Fan
75W
6 hrs
450 Wh
37.5 Ah
150W
LED TV (32")
60W
4 hrs
240 Wh
20 Ah
150–200W
Refrigerator (Mini)
100W (avg)
8 hrs
800 Wh
66.6 Ah
300–500W
Water Pump (1HP)
750W
1 hr
750 Wh
62.5 Ah
1000W
Microwave Oven
1000W
0.5 hr
500 Wh
41.6 Ah
1200–1500W
Electric Kettle
1500W
0.3 hr
450 Wh
37.5 Ah
2000W
Key Formulas
Purpose
Formula
Example
Energy Consumption (Wh)
Watts × Hours
60W × 4 hrs = 240 Wh
Battery Capacity (Ah)
Watt-hours ÷ System Voltage (V)
240 Wh ÷ 12V = 20 Ah
Inverter Size (W)
Total Watts × 1.25 (for safety margin)
300W × 1.25 = 375W → Use 400W inverter
Total Load Power (W)
Sum of all appliance watts to be used at once
Light (10W) + Fan (75W) = 85W
Runtime (hrs) of Battery
(Battery Ah × Voltage) ÷ Total Load (W)
(100Ah × 12V) ÷ 240W = 5 hrs
How To Choose The Right Products
Need / Application
Recommended Battery
Inverter Size
Notes
Basic lighting + phone charging
50Ah – 100Ah (12V)
100W–200W
For small backup setups
Home office (laptop, fan, TV)
150Ah – 200Ah (12V or 24V)
500W – 1000W
For moderate usage with 4–6 hours of backup
Home backup (fridge, lights)
200Ah+ (24V or 48V recommended)
1000W – 1500W
Ideal for longer backups or heavier loads
Business / shop power backup
300Ah+ (48V system)
2000W – 3000W
Suitable for commercial setups or extended power outages
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