EG4 FlexBOSS21 All-in-One Hybrid Inverter – 21kW PV Input | 16kW AC Output

The EG4 FlexBOSS21 is a powerful, all-in-one split-phase hybrid inverter built for residential and small commercial energy systems. With a 21kW usable PV input and up to 16kW AC output, it delivers top-tier performance for both on-grid and off-grid applications. Engineered for scalability, flexibility, and efficiency, the FlexBOSS21 is an ideal solution for modern energy systems of all sizes.

Key Performance Highlights:

• PV Input Capacity:

  • Usable PV: 21kW

  • Maximum PV Input: 24kW

• AC Output Power:

  • On-Grid (with PV/Battery): Up to 16kW @ 240V, 13.8kW @ 208V

  • Without PV (Battery Only): 12kW continuous output

  • Nominal Voltage: 120/240V | 120/208V | 240V

  • Nominal Current: 50A

  • Easily starts large appliances (e.g., 5-ton AC units)

• Grid Power Pass-Through:

  • Supports up to 90A utility input at 120/240V AC

Smart Design & Integration:

• MPPT Inputs:

  • 3 MPPTs configured as 26A / 26A / 15A

  • Supports up to 5 PV strings with up to 13A panels across 3 orientations

• Compact Footprint:

  • Dimensions: 30.4 x 22.3 x 11.2 inches

  • Weight: 121 lbs

• Warranty:

  • Backed by a 10-year manufacturer warranty

Pair With GridBOSS for Expanded Features:

When combined with the EG4 GridBOSS MID, the FlexBOSS21 unlocks even greater system functionality:

• AC Coupling Support

• Smart Load Management

• Generator Integration

• Significantly Reduced Installation Costs & Time

Together, they form a powerful, scalable energy solution that replaces multiple components, streamlining installation and lowering overall project cost.

Why Choose the EG4 FlexBOSS21?

• Highest PV Input in its Class

• Flexible System Sizing from 50A to 160A (equivalent to full 200A service)

• Cost-Effective for Any Scale

• Ideal for Whole-Home or Small Commercial Backup Power

Power smarter with the EG4 FlexBOSS21—engineered for performance, built for value, and ready for the future.

Spec Sheet