A single FlexBOSS21 paired with a deep 64kWh battery bank: four 314Ah WallMount batteries, coordinated by the GridBOSS MID. This configuration emphasizes runtime over peak power, so it's well suited to homes that want to ride out multi-day outages or shift a lot of solar into the evening.

Highlights

  • 64kWh of storage for extended outage coverage
  • Up to 12kW continuous battery-only output
  • GridBOSS load management: prioritize which circuits stay powered
  • Solar-ready with up to 21kW of PV

What's included

  • 1× EG4 FlexBOSS21 hybrid inverter
  • 4× EG4 314Ah WallMount battery (16kWh each)
  • 1× EG4 GridBOSS MID

System at a glance

AC output Up to 16kW (with PV + grid); up to 12kW continuous from batteries
Battery storage 64kWh LiFePO4
Max PV input 21kW
Energy management GridBOSS MID, 200A service entrance

Warranty & shipping

  • EG4 warranties: FlexBOSS21 10 years, WallMount batteries 10 years, GridBOSS 10 years
  • Combined weight of major components: ~1,437 lbs. Ships in multiple pieces by freight

Actual backup runtime depends on your home's loads and configuration. Solar panels, racking, breakers and wiring are not included. Professional installation by a licensed electrician is recommended.

ManufacturerEG4 Electronics (bundle)
Bundle SKUBNDL-E1664
Battery Storage64kWh
Rated Power16kW
Max PV Input21kW
Battery-Only Continuous Outputup to 12kW
Includes1x EG4 GridBOSS MID v3.1 (Microgrid Interconnect Device (MID); 200A service entrance (350A bus, software limited to 200A); 3 x 90A (12kPV, 18kPV, FlexBOSS18, FlexBOSS21))
Includes1x EG4 FlexBOSS21 Hybrid Inverter (16kW (66.7A); 12kW (50A); 21kW (STC))
Includes4x EG4 WallMount All Weather Battery 48V 314Ah 16kWh (LiFePO4; 51.2 VDC; 314Ah)
Includes4x EG4 280Ah/314Ah All Weather Conduit Box
Includes3x EG4 280Ah/314Ah WallMount Battery Paralleling Cable Kit
Includes1x EG4 FlexBOSS LCD Screen Kit
Includes1x BSB 90A AC Circuit Breaker
Includes1x Eaton CSR 200A Main Breaker

Specifications are from the manufacturer and may change. Questions? Call (888) 831-0450.

EG4 Limited Warranty (per component): GridBOSS 10-year limited; FlexBOSS21 10-year limited; WallMount 314Ah 10-year or 10,000 cycles (whichever first), prorated

GridBOSS10-year limited
FlexBOSS2110-year limited
WallMount 314Ah10-year or 10,000 cycles (whichever first), prorated
How to claimcontact original place of purchase (Sky Solar USA) / EG4

Download: EG4 GridBOSS Warranty Document

Download: EG4 FlexBOSS21 Warranty Document

Manufacturer warranties are provided by the manufacturer. Keep your invoice as proof of purchase. Questions about a warranty claim? Call (888) 831-0450.

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