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Fortress Power eVault MAX 18.5kWh Battery

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eVault Max 18.5

$6,478.99
Free shipping with delivery between Mar 08 - Mar 15
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Fortress Power eVault MAX 18.5kWh Battery | Scalable to 370kWh

High-Capacity Energy Storage for Whole-Home & Light Commercial Applications

Built to Last. Ready for Anything.

The Fortress Power eVault MAX 18.5kWh is a 48V lithium iron phosphate (LFP) battery engineered for whole-home backup, off-grid living, and commercial energy storage. Each unit offers 18.5kWh of usable capacity and can scale up to 370kWh for larger systems.

Featuring a smart Battery Management System (BMS), high efficiency, and a service-friendly top-access design, the eVault MAX delivers reliable, future-ready performance for any AC or DC-coupled energy setup.

Key Features

  • High-Capacity, Scalable Energy Storage:
    • 18.5kWh per battery, scale up to 370kWh
    • Supports backup, peak shaving, or solar self-consumption
  • Ultra-Long Battery Life:
    • 8,000+ cycles at 80% DoD
    • Over 20 years of daily usage potential
  • Top-Tier Efficiency:
    • Up to 98% round-trip efficiency at 0.5C
  • Advanced Battery Management System (BMS):
    • Cell-level monitoring, balancing, and protection
    • Communicates with compatible inverters for real-time data
  • All-Climate Durability:
    • Performs reliably in a wide temperature range
    • Suitable for indoor and outdoor installations
  • Certified for Safety and Compliance:
    • Meets UL1642, UL1973, and UL9540 standards
  • Easy-to-Install Design:
    • Top-access service panels and compact footprint
    • Installer-friendly with reduced setup complexity
  • Built-In LCD Display + Smart Integration:
    • Touchscreen shows real-time performance metrics
    • Closed-loop integration with Fortress Power inverters

Applications

  • Whole-Home Backup Power
  • Off-Grid Living & Remote Cabins
  • Time-of-Use & Peak Demand Shaving
  • Light Commercial Storage
  • Solar Self-Consumption
  • Resilient Microgrid Systems

What’s Included

  • 1 × Fortress Power eVault MAX 18.5kWh LFP Battery
  • Pre-installed Smart BMS
  • Built-in LCD Touch Display
  • User Manual & Warranty Information
  • Mounting & Wiring Accessories (varies by installer configuration)

Compatible with Fortress Power Envy and Solo inverter series, plus third-party inverters with closed-loop communication.

Specifications

Parameter Details
Total Energy18.5 kWh
Capacity360 Ah
Nominal Voltage51.2V (48V)
Voltage Range48–55 V
Recommended Charge Current150 A
Max Charge Current (Continuous)180 A
Max Discharge Current (Continuous)180 A
Max Pulse Current (10 sec)200 A
Charging Temperature32°F to 120°F
Discharging Temperature14°F to 77°F
Dimensions (H × W × D)20.3 × 20.3 × 42.2 in
Weight520 lbs
Enclosure Protection RatingIP55
Mounting OptionsFloor Standing
CertificatesUL 1642, UL1973, UL9540
Warranty10 Years
ScalabilityMaximum 20 in Parallel (370 kWh)
CommunicationCAN / RS485
High Current Circuit Breaker250A
Efficiency>98%

Understanding Your Power Needs

Power Calculation Guide

Sizing Metric Formula & Example
Energy Consumption (Wh) Formula: Watts × Hours
Example: 60W × 4 hrs = 240 Wh
Battery Capacity (Ah) Formula: Watt-hours ÷ System Voltage (V)
Example: 240 Wh ÷ 12V = 20 Ah
Inverter Size (W) Formula: Total Watts × 1.25 (safety margin)
Example: 300W × 1.25 = 375W → Use 400W inverter
Total Load Power (W) Formula: Sum of all appliance watts used simultaneously
Example: Light (10W) + Fan (75W) = 85W
Runtime (hrs) of Battery Formula: (Battery Ah × Voltage) ÷ Total Load (W)
Example: (100Ah × 12V) ÷ 240W = 5 hrs

Find Your Power Match

Need / Application System Recommendation
Basic lighting + phone charging Recommended Battery: 50Ah – 100Ah (12V)
Inverter Size: 100W – 200W
Notes: For small backup setups
Home office (laptop, fan, TV) Recommended Battery: 150Ah – 200Ah (12V or 24V)
Inverter Size: 500W – 1000W
Notes: For moderate usage with 4–6 hours of backup
Home backup (fridge, lights) Recommended Battery: 200Ah+ (24V or 48V recommended)
Inverter Size: 1000W – 1500W
Notes: Ideal for longer backups or heavier loads
Business / shop power backup Recommended Battery: 300Ah+ (48V system)
Inverter Size: 2000W – 3000W
Notes: Suitable for commercial setups or extended power outages

Why Shop With Us

  • Authorized & Trusted Dealer: We’re fully authorized for every brand we carry, so you get genuine products backed by full manufacturer warranties.
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  • Real Human Support, 7 Days a Week: Reach us by phone, email, or live chat — no bots, no overseas call centers, just experts who know off-grid power systems.
  • Expert Energy Guidance: Our solar and backup energy specialists are here to help with system design, product questions, and installation tips.
  • USA-Based Service: Local, knowledgeable, and friendly support right here in the U.S.
  • Secure Payments: Shop confidently with encrypted, secure checkout protecting your personal and payment information.
  • Built for Energy Independence: Whether powering a cabin, prepping for emergencies, or going off-grid, our products are chosen for performance, reliability, and sustainability.

Fortress Power eVault MAX 18.5kWh Battery

$6,478.99