3x ETHOS + EG4 FLEXBOSS21 ESS Off-Grid System

The BigBattery ETHOS + EG4 FlexBOSS21 system pairs modular, UL-certified 48V lithium storage with a next-generation hybrid inverter for a complete, future-ready energy solution. ETHOS provides scalable capacity, intelligent management, and a 12-year warranty for long-lasting, maintenance-free energy independence, while FlexBOSS21delivers 12kW output and up to 21,000W of PV input with 3 MPPTs, 90A grid feed-through at 120/240VAC, and seamless integration with the EG4 GridBOSS MID gateway for smart load management, AC coupling, and generator support. With built-in rapid shutdown, ground fault and arc fault protection, plus Wi-Fi monitoring and mobile alerts, this combo offers safe, efficient, and highly flexible power for modern on-grid or off-grid residential and commercial systems.

Items Included SKU

3xBigBattery ETHOS | 48V - 5.1kWh | UL1973 | Home Battery Backup LFPFETHS-48051-G1

1xETHOS Control BoxCNT060

1xEG4 FlexBOSS21 Hybrid Solar Inverter | 21kW PV / 16kW AC | Split-Phase | 4-MPPT | Scalable | Remote Wi-Fi MonitoringINV027

1x15kWh Ethos Controller to Battery Power Cable 4ft (1220mm)CBL091