Description
Description
Fortress Power Envy Duo 21 Whole-Home Hybrid Solar Inverter
Product Description
The Fortress Power Envy Duo 21 is a 48V hybrid solar inverter designed for demanding residential and light-commercial energy systems. It supports 240V split-phase and 208V three-phase configurations while delivering 12kW of continuous backup output across both configurations.
The inverter accommodates photovoltaic arrays up to 25kW, with a maximum usable PV power of 21kW. Integrated AC and DC breakers, a built-in rapid-shutdown transmitter and remote monitoring help simplify installation and ongoing system management.
- 12kW continuous backup output at 240V or 208V
- Maximum grid output of 16kW at 240V
- Maximum grid output of 13.8kW at 208V
- Supports photovoltaic arrays up to 25kW
- 21kW maximum usable photovoltaic power
- Three MPPTs with a 2:2:1 input configuration
- Supports 240V split-phase systems
- Supports 208V three-phase systems
- Compatible with Fortress Power 48V batteries
- Supports operation without a battery
- Integrated AC and DC breakers
- Built-in rapid-shutdown transmitter
- Supports up to 10 inverters in parallel
- Maximum combined output of 120kW
- Remote system monitoring through the Fortress Power mobile app
- Remote firmware updates
- NEMA 4X and IP66 protection
- Touch color screen
Specifications
| Specification | Details |
|---|---|
| Manufacturer | Fortress Power |
| Model | Envy Duo 21 |
| GTIN | 00850079800021 |
| Maximum PV Array Power | 25,000W |
| Maximum Usable PV Power | 21,000W |
| Number of MPPTs | Three |
| Inputs per MPPT | 2:2:1 |
| Maximum Usable Input Current | 26A / 26A / 15A |
| Maximum Short-Circuit Input Current | 31A / 31A / 19A |
| PV Startup Voltage | 100V |
| Nominal MPPT DC Voltage | 360V |
| DC Voltage Range | 100–550V |
| MPPT Operating Voltage Range | 120–440V |
| Backup Output Current | 50A at 240V / 57.7A at 208V |
| Backup Output Voltage | 120/240V and 120/208V |
| Continuous Backup Output | 12,000VA at 240V / 12,000VA at 208V |
| Backup Operating Frequency | 60Hz |
| Peak Backup Power | Twice rated power for 0.5 seconds |
| Backup THDv | Less than 3% |
| Switching Time | Less than 20 milliseconds |
| Maximum Grid Output Current with PV | 66.7A |
| Maximum Grid Output with PV | 16,000W at 240V / 13,800W at 208V |
| Continuous Battery-Only Output | 12,000W at 240V / 12,000W at 208V |
| Rated Grid Voltage | 120/240V and 120/208V |
| Grid Operating Voltage Range | 180–270V |
| Grid Operating Frequency | 50/60Hz |
| Grid Frequency Range | 55–65Hz |
| Power Factor | 0.99 at full load |
| Reactive Power Adjustment Range | -0.8 to +0.8 leading, adjustable |
| Grid THDi | Less than 3% |
| Synchronous Inrush Current | 35A |
| Compatible Battery Type | Lithium battery or no battery |
| Nominal Battery Voltage | 48V |
| Battery Voltage Range | 40–60V |
| Maximum Battery Charge Current | 250A |
| Maximum Battery Discharge Current | 250A |
| Maximum PV-to-Grid Efficiency | 97.50% |
| Maximum Battery-to-Grid Efficiency | 94% |
| CEC Efficiency | 96.90% |
| Maximum Parallel Units | 10 |
| Maximum Combined Output | 120kW |
| Dimensions | 22.3 × 35.2 × 11.2 inches |
| Metric Dimensions | 566 × 893 × 285 mm |
| Weight | 125.71 lbs / 57 kg |
| Protection Rating | NEMA 4X / IP66 |
| Cooling | Smart cooling fans |
| Topology | High-frequency transformerless |
| Relative Humidity | 0–100% |
| Maximum Operating Altitude | Less than 6,561 feet / 2,000 meters |
| Operating Temperature | -13°F to 140°F / -25°C to 60°C |
| Temperature Derating | Above 104°F / 40°C |
| Noise Level | Less than 67dB |
| Average Idle Consumption | 60W |
| Display | Touch color screen |
| Communication | RS485, Wi-Fi and CAN |
| Estimated Delivery | One to two weeks |
FAQs
Q: How much continuous backup power does the Envy Duo 21 provide?
A: It provides 12,000W of continuous backup output at either 240V or 208V.
Q: What is the maximum supported solar-array size?
A: It supports a photovoltaic array up to 25,000W, with maximum usable PV power of 21,000W.
Q: Does the Envy Duo 21 support three-phase power?
A: Yes. It supports 120/208V three-phase applications as well as 120/240V split-phase systems.
Q: Can multiple Envy Duo 21 inverters operate together?
A: Yes. Up to 10 units can operate in parallel for a combined output of 120kW.
Q: Is a battery required?
A: No. The listed battery configurations are lithium battery or no battery.
Whole Home Solar hybrid inverter; Max 16KW ongrid and 12KW off-grid continous output;Max 25KW PV array; 200A transfer switch: IP 65 outdoor rated; pre-built AC &DC breakers; Built-in Apsmart RSD transmitter; 120/240V Single and split phase, 120/208V three phase, 127/220V single & split phase; 50/60HZ; breakers included
