Fortress Power Envy Duo 21 48V Hybrid Solar Inverter – 16kW High-Power Output for Home & Small Business
🚀⚡ Unmatched Power; Unstoppable Performance
The Envy Duo 21 is Fortress Power’s most powerful 48V hybrid inverter, built to handle both residential and light commercial energy needs. With up to 25kW solar input and dual-phase support (240V split-phase and 208V three-phase), it delivers a reliable 12kW of continuous backup power with up to 16kW export capacity.
Perfectly paired with Fortress Power’s 48V batteries, the Envy Duo 21 offers flexible applications from whole-home backup to off-grid living. With built-in AC/DC breakers, rapid shutdown transmitter, and scalability up to 120kW, it’s a future-ready solution designed for maximum performance and long-term reliability.
Applications
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Modern Households with Growing Energy Needs
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Hybrid and Off-Grid Living
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Light Commercial Use
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DIY solar setups
Meet the Fortress Power Envy Duo 21 Dual-Phase Hybrid Inverter with 25kW PV Input
Envy Duo 21 Hybrid Inverter / Key Benefits
⚡ High PV Input, Maximum Generation
Handles up to 25kW of solar input, so you
can generate more solar production and store more energy from your system—perfect for larger homes or small businesses.
🔌 Flexible Voltage for Any Setup
Works with both 240V split-phase and 208V three-phase setups, giving you compatibility across different grid types
without extra equipment.
🔋 Streamlined Battery Integration
Optimized for Fortress Power 48V batteries, delivering 12kW continuous output and up to 16kW peak, ensuring whole-home or business backup without compromise.
📈 Expandable as You Grow
Expand your system by connecting up to 10 inverters in parallel, allowing your energy capacity to grow as your needs
increase—without a full redesign.
🛠️ Simplified, Code-Compliant Installation
Comes with built-in AC/DC breakers and a rapid shutdown transmitter, cutting installation time and keeping your system safe and compliant from day one.
📱 Smart Monitoring Anywhere
Track solar production, battery health, and energy usage directly from the Fortress Power mobile app, with remote firmware updates to keep your system running at its best.
Envy Duo 21 Feature Videos
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Envy Duo 21 Installation Videos
Step-by-step setup guide. Coming Soon~
Envy Duo 21 Influencer Videos
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Envy Duo 21 Hybrid Inverter Technical Specs & Downloads
Get the details you need—spec sheets, manuals, and performance data all in one place. We link directly to the manufacturer's site, so you know you always have the most up-to-date information.
| PV Output Data | |
| Number of MPPT | 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. Power (W) | 21000 |
| Max. PV ARRAY POWER (W) | 25000 |
| Backup Output Data | |
| Nominal output current (A) | 50@240V, 57.7@208V |
| Nominal output voltage (V) | (120/240), (120/208) |
| Continuous output power (VA) | 12000@240V, 12000@208V |
| Operating frequency (Hz) | 60 & 50 |
| Peak power (VA) | 2xPn, 0.5s |
| THDV | <3% |
| Switching Time (ms) | <20 |
| General Data | |
| Paralleling Capabiliy | Up to 10 units (120kW) |
| Dimensions | 22.3 x 35.2 x 11.2 in (566 x 893 x 285 mm) |
| Weight | 125.71 lbs (57 kg) |
| Degree of protection | NEMA4X / IP66 |
| Cooling concept | Smart Cooling Fans |
| Topology | High Frequency Transformer-less |
| Relative humidity | 0-100% |
| Altitude (m) | <6561ft. (<2000m) |
| Operating Temperature Range (ºC) | -25~60>40 Derating |
| Noise emission (dB) | <67 |
| Idle Consumption AVG (W) | 60 |
| Display | Touch color screen |
| Communication interface | Rs485/ Wi-Fi/ CAN |
| AC Grid Output Data | |
| Max. Output Current with pv (A) | 66.7 |
| Max. Output Power with pv (W) | 16000@240V 13800@208V |
| Continuous power output with battery only (W) | 12000@240V, 12000@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 |
| Reactive power adjust range | -0.8~+0.8 leadingAdjustable |
| THDI | <3% |
| Sync inrush current (A) | 35 |
| Efficiency | |
| Max. EFFICIENCY PV to grid | 97.50% |
| Max. EFFICIENCY battery to grid | 94% |
| CEC Efficiency | 96.90% |
| Battery Data | |
| Type | Lithium battery/ No Battery |
| Max. charge current (A) | 250 |
| Max. discharge current (A) | 250 |
| Nominal voltage (V) | 48 |
| Voltage range (V) | 40-60 |
