Fortress Power FlexTower: The Ultimate All-in-One Energy Storage Solution

The Fortress Power FlexTower Full System Enclosure redefines residential and light commercial energy storage by combining a powerful battery and a hybrid inverter into a single, sleek, and pre-wired enclosure. With its robust engineering and comprehensive feature set, the FlexTower Full System Enclosure delivers a streamlined path to achieving total energy independence, ensuring your home remains powered through outages, high-cost periods, and beyond.

Engineered for Simplified Installation and Unrivaled Durability

Designed with the installer in mind, the FlexTower Top Enclosure features a simplified, all-in-one approach that drastically reduces hardware costs and installation time. The unit’s built-in 200A grid pass-through capability eliminates the need for a separate backup subpanel. The enclosure comes with integrated busbars and pre-cut side knockouts for clean AC, DC, and generator wiring, making every connection straightforward and professional.  For maximum convenience, battery cables with Anderson connectors are included with the Fortress Power DuraRack for easy stacking and installation.

The FlexTower Top Enclosure is designed to house the Fortress Power Envy 12kW Inverter while the Fortress Power DuraRack can hold up to four Fortress eFlex or eFlex MAX batteries, providing a scalable storage capacity of up to 21.6 kWh per unit. This enclosure is constructed from durable carbon steel and holds a NEMA 3R rating, signifying protection against rain, sleet, snow, and external ice formation. It is also IP65 water and dust resistant, making it safe and reliable for both indoor and outdoor installations. This robust construction ensures that the internal components—including the batteries and inverter—are shielded from the elements, ensuring consistent performance year-round.

Advanced Technology for Maximum Performance and Safety

At the heart of the Fortress FlexTower Full System Enclosure is its high-performance energy technology. The Fortress FlexTower Top Enclosure is fully compliant with the latest safety and performance standards, holding certifications including UL1741, UL1741-SA, UL1973, and UL9540 (A), which are crucial for ensuring safety and regulatory compliance. The Fortress FlexTower DuraRack carries  certifications that include UL9540, UL9540(A), UL1973, CEC, SGIP, ensuring piece of mind for installers, home-owners, and guides towards a seamless permitting process. 

The integrated hybrid inverter and batteries work in harmony to achieve extraordinary efficiency. With a round-trip battery efficiency of over 98% and a CEC-rated inverter performance, the Fortress Power FlexTower Full System Enclosure ensures you get the most out of every kilowatt-hour your solar array produces. To keep your Fortress Envy 12kW in top performance condition, the Fortress Power Top Enclosure utilizes built in cooling fans, to keep your inverter at a prime temperature To ensure optimal battery health in colder climates, the Fortress Power DuraRack supports the addition of DIN-rail heaters, allowing the batteries to operate within their optimal temperature range.

Flexible and Scalable for Every Application

The FlexTower supports a wide range of applications including whole-home backup, off-grid power, Time-of-Use (TOU) optimization and Virtual Power Plant (VPP) participation. Its flexibility is further enhanced by its support for both AC and DC coupling, allowing it to seamlessly integrate with new or existing solar PV arrays. For larger energy needs, multiple Fortress Power FlexTowers can be expanded to create a truly formidable energy storage system.

The system's built-in LCD touchscreen combined with remote monitoring and control via a dedicated app allows you to track your energy flow, receive alerts, and optimize your system from anywhere. With its combination of intelligent design, robust construction, and advanced capabilities, the Fortress Power FlexTower Full System Enclosure is the perfect choice for homeowners and professionals seeking a reliable, high-performance, and future-proof energy storage solution.

Technical Downloads

Data Sheet

Installation Manual

Technical Notes

FlexTower UL9540 Certification