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EG4| FlexBOSS21 16kW (21kPV) Hybrid Inverter
EG4| FlexBOSS21 16kW (21kPV) Hybrid Inverter
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The latest development from the EG4 team, the FlexBOSS18 is a cutting-edge, split-phase hybrid inverter designed to be the keystone of any residential or commercial power system. With an incredible 18kW PV input capacity and an array of advanced features, the FlexBOSS18 provides reliable performance day in and day out, in both on-grid and off-grid settings.
The FlexBOSS18 is one of the highest capacity inverters on the market today, featuring 2 MPPTs supporting up to 4 strings, providing superior flexibility for multi-orientation solar arrays, and the ability to handle 90A of grid feed-through at 120/240VAC, ensuring robust grid-tied capabilities. Plus, the FlexBOSS18 seamlessly integrates with EG4’s GridBOSS MID power gateway for a cost-effective, streamlined setup, helping to reduce installation time and system startup costs, and when you pair these two units together in your system, you’re able to utilize the smart load management, AC coupling, and generator support features if needed.
The latest development from the EG4 team, the FlexBOSS21 is a cutting-edge, split-phase hybrid inverter designed to be the keystone of any residential or commercial power system. With an incredible 21kW PV input capacity and an array of advanced features, the FlexBOSS21 provides reliable performance day in and day out, in both on-grid and off-grid settings.
The FlexBOSS21 is one of the highest capacity inverters on the market today, featuring 3 MPPTs supporting up to 5 strings, providing superior flexibility for multi-orientation solar arrays, and the ability to handle 90A of grid feed-through at 120/240VAC, ensuring robust grid-tied capabilities. Plus, the FlexBOSS21 seamlessly integrates with EG4’s GridBOSS MID power gateway for a cost-effective, streamlined setup, helping to reduce installation time and system startup costs, and when you pair these two units together in your system, you’re able to utilize the smart load management, AC coupling, and generator support features if needed.
But that’s not all. EG4 understands the value of enhanced safety and visibility when it comes to your power, and the FlexBOSS21 spares no expense, coming equipped with responsive rapid shutdown, ground fault monitoring, and arc fault protection, all backed by industry-leading safety certifications, and with EG4’s updated monitoring software, you get access to remote management, mobile notifications, and convenient Wi-Fi connectivity for your system.
Combining efficiency, scalability, and cutting-edge technology, the FlexBOSS21 is a top-tier solution, with a safety-first design, for those seeking a reliable, powerful inverter to anchor their energy system. Whether for residential or commercial applications, its advanced features and versatile design provide unmatched value and peace of mind. Elevate your energy independence and power your future with the EG4 FlexBOSS21 Hybrid Inverter today.
Features
Suitable For
Tech Specs
AC INPUT
Nominal AC Voltage: | 120/240VAC | 120/208VAC (L1/L2/N required) |
Frequency: | 60 Hz (Default) | 50 Hz |
Max. AC Current: | 54A @ 240V | 54A @ 208V |
Max. AC Input Power: | 13000W |
Max. AC Bypass: | 90A |
AC GRID OUTPUT
Operating Voltage Range: | 180 – 270VAC |
Output Voltage: |
120/240VAC | 120/208VAC (L1/L2/N required) |
Max. Output Current: | 66.7A |
Output Frequency: | 60 Hz (Default) | 50 Hz |
Nominal Output Power (without PV): | 12000W @ 240V | 12000W @ 208V |
Nominal Output Power (with PV): | 16000W @ 240V | 13800kW @ 208V |
Power Factor: | 0.99 (Full Load) |
Reactive Power Adjustment Range: | -0.8 – 0.8 Leading Adjustable |
Total Harmonic Distortion: | <5% (Full Load) |
Transfer Time: | 20ms (Default) | 10ms (Configurable) | 20ms (Parallel) |
AC BACKUP / UPS OUTPUT
Rated Output Current: | 50A @ 240V | 57.7A @ 208V |
Nominal Output Voltage: | 120/240VAC | 120/208VAC |
Rated Output Power: | 12000W @ 240VAC | 12000W @ 208VAC |
Peak Power: |
20000W (0.5 sec) | 15000W (1 sec) 12500W (6 min) | 11000W (12 min) |
Operating Frequency: | 60 Hz (Default) | 50 Hz |
Total Harmonic Distortion Voltage: | <5% |
Transfer Time: | 20ms (Default) | 10ms (Configurable) | 20ms (Parallel) |
PV INPUT
No. of MPPTs: | 2 |
Inputs per MPPT: | 2 (MPPT 1) | 2 (MPPT 2) |
Max. Usable Input Current: | 26A (MPPT 1) | 26A (MPPT 2) |
Max. Short Circuit Input Current: | 31A (MPPT 1) | 31A (MPPT 2) |
DC Input Voltage Range: | 100 – 600VDC |
Unit Start-Up Voltage: | 200VDC |
MPPT Operating Voltage Range: | 120 – 440VDC |
Nominal MPPT Voltage: | 360VDC |
Max. Utilized PV Array Power:18 | 18000W |
Max. Recommended PV Input: | 18000W |
Max. Efficiency: | 97.5% (PV to Grid) | 94.5% (PV to Battery) | 94% (Battery to Grid) |
Idle Consumption: | <65W |
BATTERY
Nominal Voltage: | 48VDC |
Voltage Range: | 40 – 60VDC |
Max. Charge / Discharge Power: | 10000W |
Recommended Battery Capacity per Inverter: | >300Ah |
OPERATING ENVIRONMENT
Operating / Storage Temperature Range: | -13ºF – 140ºF (-25ºC – 60ºC) |
Operating Altitude: | <6,561 ft (2000 m) |
Relative Humidity: | 0 – 100% |
Typical Noise Emission: | <50dB @ 3 ft |
Design Topology: | High-Frequency / Transformerless |
Protection Rating: | IP65 / NEMA 4X |
Communications: | RS485 / CANBus / WiFi / 4G |
Max. Parallel Connections: | 10 |
DIMENSIONS
Weight: | 115 lbs (52 kg) |
Depth: | 11.2 in (287 mm) |
Width: | 22.8 in (567 mm) |
Height: | 30.5 in (775 mm) |
Inverters Downloads
Spec Sheet |
User Manual |
UL1741 Certificate |



