BigBattery ETHOS + EG4 FLEXBOSS18 ESS 3-Phase Energy Storage System

Description BigBattery ETHOS + EG4 FlexBOSS18 ESS — 3-Phase Energy Storage System | LiFePO4 | UL Certified The BigBattery ETHOS™ + EG4 FlexBOSS18 ESS is a complete, high-performance energy storage system engineered for both on-grid and off-grid applications. This 3-phase configuration pairs the scalable ETHOS 48V LiFePO4 battery system with three EG4 FlexBOSS18 hybrid inverters, delivering an intelligently integrated solution capable of handling serious residential and light commercial energy demands. Expandable to 80+ kWh, built to UL 9540 certified standards, and backed by lifetime U.S.-based technical support — this is backup power and energy independence done right. Complete ESS Solution — Battery and inverter system pre-configured to work seamlessly together out of the box 18,000W PV Input Per Inverter — High solar capacity with dual MPPT optimization on each FlexBOSS18 unit 3-Phase Output — Three FlexBOSS18 inverters deliver 120/240V split-phase power for flexible residential and light commercial load support LiFePO4 Battery Chemistry — Safe, stable lithium iron phosphate technology with 6,000+ cycle life Scalable to 80+ kWh — Modular ETHOS battery system supports future expansion as energy needs grow Closed-Loop Communication — CANBus/RS485 integration ensures optimized coordination between battery and inverter GridBOSS Integration Ready — Supports advanced load management, AC coupling, and generator integration via the EG4 GridBOSS MID gateway Advanced Safety Protections — Rapid shutdown, ground fault, and arc fault protection included Remote Monitoring & Alerts — Wi-Fi and 4G connectivity with real-time system tracking Maintenance-Free Operation — No routine servicing required IP65 / NEMA 4X Rated — Both battery and inverter carry robust weatherproof protection ratings Ships from Texas, USA — 12-year battery warranty | 10-year inverter warranty | Lifetime USA-based tech support Specifications BATTERY SPECIFICATIONS (per ETHOS module) Spec Detail GTIN-12 (U.P.C.) 850061252005 System Voltage 48V Nominal Voltage 51.2V Chemistry LiFePO4 kWh Capacity 10.24 kWh Ah Capacity 200Ah Charging Voltage Range 55.6 – 57V Max Charge Voltage 57V Operating Voltage Range 48 – 57V Suggested Low Voltage Cutoff 48 – 50.8V BMS Cutoff Range 42 – 47V Cell Configuration 16S 2P Max Continuous Discharge Current 200A Max Continuous Power 10,240W Max Discharge Peak Current 300A (max 5 seconds) Max Charge Current 200A Charge Temperature Range 32°F – 113°F (0°C – 45°C) Discharge Temperature Range -4°F – 140°F (-20°C – 60°C) Optimal Discharge Temperature Range 59°F – 95°F (15°C – 35°C) Storage Temperature Range (SoC >50%) -4°F – 113°F (-20°C – 45°C) (max 6 months) Weight 273 lb (123.8 kg) Dimensions (D × W × H) 6.7 in × 26.5 in × 43.3 in (170 mm × 674 mm × 1100 mm) Max Parallel Connections Up to 16 per control box Protection Rating IP65 / NEMA 4X Communications CANBus / RS485 Certifications UL9540, UL9540A, UL1973, UN38.3 INVERTER SPECIFICATIONS (per EG4 FlexBOSS18 unit) Spec Detail 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 13,000W Max. AC Bypass 90A Operating Voltage Range 180 – 270VAC Output Voltage 120/240VAC | 120/208VAC Max. Output Current 66.7A Nominal Output Power (without PV) 12,000W @ 240V | 12,000W @ 208V Nominal Output Power (with PV) 16,000W @ 240V | 13,800W @ 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) Rated Output Power 12,000W @ 240VAC | 12,000W @ 208VAC Peak Power 20,000W (0.5 sec) | 15,000W (1 sec) | 12,500W (6 min) | 11,000W (12 min) Number 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. Recommended PV Input 18,000W Max. Efficiency 97.5% (PV to Grid) | 94.5% (PV to Battery) | 94% (Battery to Grid) Idle Consumption <65W Battery Nominal Voltage 48VDC Battery Voltage Range 40 – 60VDC Max. Charge / Discharge Power 10,000W Recommended Battery Capacity per Inverter >300Ah Operating / Storage Temperature Range -13°F – 140°F (-25°C – 60°C) Operating Altitude <6,561 ft (2,000 m) Relative Humidity 0 – 100% Typical Noise Emission <50dB @ 3 ft Design Topology High-Frequency / Transformerless Protection Rating IP65 / NEMA 4X Communications RS485 / CANBus / Wi-Fi / 4G Max. Parallel Connections 10 Weight 115 lbs (52 kg) Dimensions (D × W × H) 11.2 in × 22.8 in × 30.5 in (287 mm × 567 mm × 775 mm) Certifications UL1741 FAQs Q: Is this system compatible with both on-grid and off-grid setups? A: Yes. The ETHOS + EG4 FlexBOSS18 ESS is designed for both on-grid and off-grid applications, and supports grid-tied, hybrid, and off-grid installations. Q: Can I expand the battery capacity of this system in the future? A: Yes. The ETHOS battery system is modular and scalable up to 80+ kWh, allowing you to add additional ETHOS modules as your energy storage needs grow. Q: What certifications does this energy storage system carry? A: The ETHOS battery holds UL9540, UL9540A, UL1973, and UN38.3 certifications. The EG4 FlexBOSS18 inverter is UL1741 certified. The combined system also has a CEC Listing. Q: How long is the warranty on this system? A: The ETHOS battery carries a 12-year warranty and the EG4 FlexBOSS18 inverter carries a 10-year warranty. Lifetime USA-based technical support is also included. Q: Does this system support remote monitoring? A: Yes. The EG4 FlexBOSS18 inverter includes Wi-Fi and 4G connectivity for real-time monitoring and alerts.