Fortress Power Envy 8kW 48V All-in-One Hybrid Inverter, 13kW Solar Input, Dual MPPT, 60A AC Passthrough, Built-In Rapid Shutdown, IP65, UL 1741

The Fortress Power Envy 8kW is an all-in-one hybrid inverter that combines a solar inverter, 167A battery charger, and transfer switch into a single IP65-rated enclosure. It delivers 8,000W of continuous split-phase 120/240Vac output and supports both grid-tied and off-grid operation, making it a versatile choice for whole-home backup, solar self-consumption, and off-grid living. The Envy 8kW is the entry-level model in the Fortress Power Envy line, offering the same feature set and build quality as the larger 10kW and 12kW versions in a package sized for smaller homes, essential load backup, or budget-conscious installations.

Solar Input

The Envy 8kW has two independent MPPT channels with two string inputs each (four total PV inputs). Each MPPT accepts up to 6,000W, for a combined maximum PV input of 13,000W. The DC input voltage range spans 100-600Vdc (550V max recommended), with a nominal input voltage of 360Vdc and a full power MPPT operating range of 170-500Vdc. Maximum usable input current is 25A per MPPT, with a short circuit rating of 31A per MPPT. Of the 13kW solar capacity, up to 12kW can be delivered simultaneously to the battery bank and AC outputs. This means the Envy 8kW can charge batteries and power household loads from solar at the same time without throttling either function during peak production hours.

Grid and Generator Integration

The Envy 8kW features a 14,400W AC passthrough at 240V for grid power. When the grid is available, the inverter can pass power directly to household loads while simultaneously charging the battery bank. A dedicated auto-start generator port rated at 50A / 12kW allows a backup generator to charge batteries and run loads when both solar and grid are unavailable. Built-in 63A AC breakers cover grid input, load output, and the generator connection, while a 250A DC breaker protects the battery circuit. The inverter manages the transition between grid, generator, solar, and battery power automatically, with a switching time of less than 20ms.

For grid-tied systems, the Envy 8kW can export up to 8,000W back to the utility at 240V. It supports net metering, time-of-use optimization, peak shaving, and zero-export modes. The inverter is VPP (Virtual Power Plant) compatible and approved by utilities across the U.S. and Puerto Rico, which means homeowners can participate in demand response programs and receive compensation for discharging stored energy during peak grid demand.

Battery Compatibility

The Envy 8kW operates on a 48Vdc nominal battery bus with a voltage range of 40-60Vdc. It supports a maximum charge and discharge current of 167A and a maximum charge/discharge power of 8,000W. The inverter communicates with battery management systems through closed-loop protocols for real-time monitoring of voltage, current, temperature, and SOC (State of Charge).

Fortress Power designed the Envy to pair directly with their own battery lineup, including the eVault MAX 18.5kWh, eFlex 5.4kWh, eFlex MAX 5.4kWh, eForce, eBoost, and LFP-10 MAX systems. Other lithium batteries can be connected in open-loop mode, and lead-acid batteries are also supported.

Scalability

A single Envy 8kW handles most essential load scenarios, but the inverter supports parallel operation of up to 10 units for a combined output of 80kW. Two or more units can also be configured for commercial three-phase 120/208V or 127/220V output, making the Envy a flexible platform for mixed-use residential and light commercial projects.

Built-In Safety and Code Compliance

The Envy 8kW comes with a built-in APsmart Module Level Rapid Shutdown (RSD) transmitter and button, meeting NEC 690.12 requirements without additional external hardware. It is also compatible with Tigo transmitters for installations that use Tigo optimizers. The integrated 63A AC breakers and 250A DC battery breaker are built into the enclosure, reducing the number of external disconnect components and cutting down installation time.

Monitoring

The Fortress Power Guardian mobile app provides remote monitoring, system status, performance data, and firmware updates. Installers and homeowners can view real-time solar production, battery SOC, grid consumption, and inverter status from anywhere. The inverter communicates via RS485, Wi-Fi, and CAN interfaces. A color LCD touchscreen on the unit provides local access to settings and system status. Batch settings allow installers to configure multiple units quickly during multi-inverter installations.

Enclosure and Installation

The Envy 8kW is NEMA 4X / IP65 rated, meaning it can be installed indoors or outdoors without additional weatherproofing. The enclosure includes a color LCD touchscreen for local configuration and status monitoring. The unit weighs 110 lbs (50 kg) and measures 29.5 x 20.5 x 11.23 inches (750 x 520 x 285 mm). Internal wire management space is generous, which is a practical advantage during installation. The operating temperature range is -13°F to 140°F (-25°C to 60°C).

Output Quality

The Envy 8kW produces a pure sine wave output at 120/240Vac split-phase, and also supports 120/208V and 208V three-phase configurations. Maximum efficiency is rated at 97.5% (CEC weighted: 96.5%). Surge capacity reaches 16kW for 500ms, which is enough to handle motor startup on compressors, well pumps, and similar inductive loads.

Certifications

The Envy 8kW is certified to UL 1741 and UL 1741 SB for grid-interactive safety, IEEE 1547A for interconnection standards, California Rule 21 (Phase I, II, III), FCC 15 Class B for EMC, and is approved for HECO, CEC, Luma, SGIP, ISO-NE, and NOM programs. It includes anti-islanding protection, SPD (surge protection device), AFCI (arc fault circuit interrupter), and ground fault monitoring.