EG4 FlexBOSS21 Hybrid Inverter | 48V Split Phase | 21kW PV Input

EG4 FlexBOSS21 Hybrid Inverter
Revolutionize your home or small commercial solar setup with the EG4 FlexBOSS21—a split-phase, all-in-one hybrid inverter featuring 21kW of usable PV (DC) input. Delivering up to 16kW AC power under sunlight (and 12kW without solar assistance), the FlexBOSS21 seamlessly feed-throughs 90 Amps of utility power at 120/240 VAC, making it an ideal solution for large or growing installations.

When combined with the EG4 GridBOSS Microgrid Interconnect Device (MID), this powerful pair drastically cuts installation costs and complexity, enabling flexible AC coupling, smart load management, and generator backup—all in one integrated system.

Key Features & Benefits

1. Industry-Leading PV Capacity

   • 21kW of usable PV input (up to 24kW max)
   • Three MPPTs (26A/26A/15A) supporting up to 5 strings at multiple orientations

2. High-Performance AC Output

   • 16kW to loads/grid under solar-battery assistance (13.8kW at 208V)
   • 12kW continuous to loads/battery without direct PV input
   • Easily starts a 5-ton AC unit, handling large surge loads

3. Feed-Through 90A Utility Power

   • Supports up to 200A service equivalence, perfect for scaling from small to large systems
   • Integrates smoothly with GridBOSS for AC coupling and generator usage

4. Flexible & Scalable

   • Expandable design grows with your energy demands
   • Compact footprint (30.4 × 22.3 × 11.2 in., 88 lbs.) simplifies installation

5. Cost-Effective & Powerful

   • Lower balance-of-system costs when paired with GridBOSS
   • Ideal for residential or light commercial sites needing reliable, high-capacity power

6. 10-Year Warranty

   • Backed by EG4’s renowned customer support and service

Achieve maximum efficiency, robust power output, and simplified installation with the EG4 FlexBOSS21. Whether you’re expanding an existing setup, going partially off-grid, or building a new system from the ground up, the FlexBOSS21 offers industry-leading PV capacity, seamless hybrid functionality, and streamlined integration for unmatched performance in solar power generation.

Spec Sheet: Download

Manual: Download

***If you've purchased an EG4 FlexBoss21 Inverter through Portable Sun, be sure to use the customer code 'PortableSun' when setting up the monitoring system!