Fortress Power Envy Duo 21 Hybrid Inverter | 48V up to 16 kWh AC Output | 120V/240V Split-Phase or 208V 3-Phase
£3,120.03
Sale price
£3,120.03
Regular price
£5,178.99
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Fortress Power Envy Duo 21 Hybrid Inverter | 48V up to 16 kWh AC Output | 120V/240V Split-Phase or 208V 3-Phase
£3,120.03
Sale price
£3,120.03
Regular price
£5,178.99
Shipping calculated at checkout.
FP-ENVYDUO-21
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Description
Fortress Power Envy Duo 21 — a high-capacity 48V hybrid inverter engineered to dominate larger residential and light commercial solar-plus-storage installations.
Key Features:
- Triple MPPT with Up to 25,000W Solar Input: Three independent MPPTs with a 21kW inverter capacity handle large-scale arrays with maximum energy harvest efficiency.
- Dual-Phase Compatibility — 240V Split-Phase and 208V Three-Phase: Delivers 12kW of continuous backup output across both configurations, with up to 16kW max export power.
- Parallel Scalability Up to 120kW: Stack up to 10 units to grow your system capacity without a complete redesign, future-proofing every installation.
- Integrated AC/DC Breakers with Built-In Rapid Shutdown Transmitter: Factory-installed safety components streamline installation and ensure full code compliance out of the box.
- 250A Max Charge and Discharge with <20ms Switching Time: Paired with Fortress Power 48V batteries, the Envy Duo 21 delivers seamless, high-current backup with near-instant transfer.
The Fortress Power Envy Duo 21 sets a new benchmark for hybrid inverter performance in demanding energy environments. With a transformer-less high-frequency topology and 97.5% peak PV-to-grid efficiency, this inverter converts and delivers power with exceptional precision and minimal loss.
Purpose-built for versatility, the Envy Duo 21 supports backup, off-grid, zero export, time-of-use, net metering, virtual power plant, peak shaving, smart load, and microgrid applications — all within one powerful wall-mounted cabinet. The intuitive touch color display and full Wi-Fi, RS485, and CAN connectivity deliver complete real-time visibility and remote control from anywhere.
Rated for operation from -25°C to 60°C with IP66 and NEMA4X weatherproofing, the Envy Duo 21 is engineered to perform in the harshest conditions. Backed by a 10-year standard warranty and a full suite of certifications including UL1741SA, UL1741SB, and Rule 21, this inverter is the definitive choice for installers and homeowners who refuse to settle.
Technical Specifications
| Specification | FP-ENVY DUO 21 |
|---|---|
| PV INPUT | |
| Number of MPPTs | 3 |
| Inputs per MPPT | 2 / 2 / 1 |
| Max. Usable Input Current (A) | 26 / 26 / 15 |
| Max. Short Circuit Input Current (A) | 31 / 31 / 19 |
| Start Input Voltage (V) | 100 |
| MPPT DC Nominal Voltage (V) | 360 |
| DC Voltage Range (V) | 100–550 |
| MPPT Operating Voltage Range (V) | 120–440 |
| Max. Inverter Power (W) | 21,000 |
| Max. PV Array Power (W) | 25,000 |
| AC GRID OUTPUT | |
| Max. Output Current with PV (A) | 66.7 |
| Max. Output Power with PV (W) | 16,000 @ 240V / 13,800 @ 208V |
| Continuous Power Output — Battery Only (W) | 12,000 @ 240V / 12,000 @ 208V |
| Rated Voltage (V) | 120/240, 120/208 |
| Operating Voltage Range (V) | 180–270 |
| Operating Frequency (Hz) | 50/60 |
| Operating Frequency Range (Hz) | 55–65 |
| Power Factor | 0.99 @ Full Load |
| THDI | <3% |
| Sync Inrush Current (A) | 35 |
| BACKUP OUTPUT | |
| Nominal Output Current (A) | 50 @ 240V / 57.7 @ 208V |
| Nominal Output Voltage (V) | 120/240, 120/208 |
| Continuous Output Power (VA) | 12,000 @ 240V / 12,000 @ 208V |
| Peak Power (VA) | 2x Pn, 0.5s |
| Switching Time (ms) | <20 |
| THDV | <3% |
| EFFICIENCY | |
| Max. Efficiency PV to Grid | 97.5% |
| Max. Efficiency Battery to Grid | 94% |
| CEC Efficiency | 96.9% |
| BATTERY | |
| Compatible Battery Type | Lithium / No Battery |
| Nominal Battery Voltage (V) | 48 |
| Battery Voltage Range (V) | 40–60 |
| Max. Charge Current (A) | 250 |
| Max. Discharge Current (A) | 250 |
| GENERAL | |
| Dimensions (in) | 22.3 x 35.2 x 11.2 |
| Weight | 125.71 lbs |
| Degree of Protection | NEMA4X / IP66 |
| Cooling | Smart Cooling Fans |
| Topology | High Frequency Transformer-less |
| Operating Temperature | -25°C to 60°C (Derating >40°C) |
| Relative Humidity | 0–100% |
| Max. Altitude | <6,561 ft (<2,000 m) |
| Noise Emission | <67 dB |
| Idle Consumption (W) | 60 |
| Display | Touch Color Screen |
| Communication | RS485 / Wi-Fi / CAN |
| Paralleling Capability | Up to 10 Units (120kW) |
| AFCI | Yes |
| RSD | Yes |
| Standard Warranty | 10 Years |
Return policy
Our goal is for every customer to be totally satisfied with their purchase. If this isn't the case, let us know and we'll do our best to work with you to make it right.
Shipping
We will work quickly to ship your order as soon as possible. Once your order has shipped, you will receive an email with further information. Delivery times vary depending on your location.
Manufacturing
Our products are manufactured both locally and globally. We carefully select our manufacturing partners to ensure our products are high quality and a fair value.