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BigBattery ETHOS 48V LifePO4 Batteries + EG4 FlexBOSS18 13kW 48V Hybrid Solar Inverter - Off Grid Stores
by BigBattery

BigBattery ETHOS 48V LifePO4 Batteries + EG4 FlexBOSS18 13kW 48V Hybrid Solar Inverter

SKU: K0231
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Bundle Options: 3 x Battery Modules + EG4 FlexBOSS18 Inverter

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BigBattery ETHOS 48V LifePO4 Batteries + EG4 FlexBOSS18 13kW 48V Hybrid Solar Inverter

BigBattery ETHOS 48V LifePO4 Batteries + EG4 FlexBOSS18 13kW 48V Hybrid Solar Inverter

The BigBattery ETHOS™ + EG4 FlexBOSS18 ESS System is a complete, high-performance energy solution designed for both on-grid and off-grid applications. Combining the scalable ETHOS 48V lithium battery system with the powerful FlexBOSS18 hybrid inverter, this system delivers reliable, efficient, and intelligent energy management in one integrated package.

Expandable up to 80+ kWh, the ETHOS battery adapts to your energy needs – while the FlexBOSS18 provides up to 18,000W PV input, dual MPPTs, and 120/240V split-phase output for flexible system design and strong performance. Integrated with the GridBOSS MID gateway, the system enables advanced energy control, including load management, AC coupling, and generator integration.

Designed with UL 9540 certified configurations, advanced battery management, and U.S.-engineered components, this system ensures safe, maintenance-free performance with seamless closed-loop communication and real-time monitoring.

Compatibility

Integrated & Optimized System:

  • ETHOS Battery System + EG4 FlexBOSS18 Hybrid Inverter


Expandable & Flexible:

  • Scalable ETHOS battery capacity up to 80+ kWh
  • Compatible with additional ETHOS modules for future expansion
  • Supports grid-tied, hybrid, and off-grid installations

Key Features

  • Complete ESS Solution – Battery + inverter system designed to work seamlessly together
  • 18,000W PV Input – High solar capacity with dual MPPT optimization
  • 120/240V Split-Phase Output – Powers residential and light commercial loads
  • LiFePO₄ Battery Chemistry – Safe, stable lithium technology with long lifespan
  • 6,000+ Cycle Life – Built for years of daily use and long-term savings
  • Closed-Loop Communication – Optimized coordination between battery and inverter
  • GridBOSS Integration – Advanced load management, AC coupling, and generator support
  • Advanced Safety Protections – Includes rapid shutdown, ground fault, and arc fault protection
  • Modular Expansion – Easily scale storage capacity as energy needs grow
  • Remote Monitoring & Alerts – Wi-Fi connectivity with real-time system tracking
  • Maintenance-Free Operation – No routine servicing required

A complete, scalable energy storage system built for performance, flexibility, and long-term independence – backed by safety, smart controls, and U.S.-based support.

Specifications:

BigBattery ETHOS 48V 5.12kWh Stackable LiFePO4 Battery Module
System Voltage 48V
Nominal Voltage 51.2V
Chemistry LiFePO4
kWh Capacity 5.12kWh
Ah Capacity 100Ah
Charging Voltage Range 55.6 - 57V
Max Charge Voltage 57V
Operating Voltage Range 48 – 57V
Suggested Low Voltage Cutoff 48 – 50.8V
Cell Configuration 16S
Max Continuous Discharge Current 100A
Max Continuous Power 5120W
Max Discharge Peak Current 150A (Max 5 seconds)
Max Charge Current 100A
Charge Temperature Range 32°F - 113°F
Discharge Temperature Range -4°F - 140°F
Optimal Discharge Temperature Range 59°F - 95°F
Storage Temperature Range (SoC >50%) -4°F - 113°F (Max 6 months)
Depth x Width x Height 6.7 in x 26.5 in x 16.5 in
Max Connections Up to (16) parallel connections
per control box
Protection Rating IP65
Communications CANBus / RS485
Certifications UL9540a, UL1973, & UN38.3
BigBattery ETHOS Control Box
Operating Voltage Range 30 - 60V
Max Continuous Discharge Current 200A
Max Charge Current 200A
Charge Temperature Range -4°F - 122°F
Discharge Temperature Range -4°F - 122°F
Optimal Discharge Temperature Range -4°F - 122°F
Weight 22 lbs
Depth x Width x Height 6.7 in x 26.5 in x 8.3 in
Max Connections Up to (16) parallel connections
per control box
Communications CANBus / RS485
EG4 FlexBOSS18 13kW 48V Split Phase AC Hybrid Inverter
AC INPUT
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 13000W
Max. AC Bypass 90A
AC GRID OUTPUT
Operating Voltage Range 180 – 270VAC
Output Voltage 120/240VAC | 120/208VAC
(L1/L2/N required)
Max. Output Current 66.7A
Output Frequency 60 Hz (Default) | 50 Hz
Nominal Output Power (without PV) 12000W @ 240V | 12000W @ 208V
Nominal Output Power (with PV) 16000W @ 240V | 13800kW @ 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)
AC BACKUP / UPS OUTPUT
Rated Output Current 50A @ 240V | 57.7A @ 208V
Nominal Output Voltage 120/240VAC | 120/208VAC
Rated Output Power 12000W @ 240VAC | 12000W @ 208VAC
Peak Power 20000W (0.5 sec) | 15000W (1 sec)
12500W (6 min) | 11000W (12 min)
Operating Frequency 60 Hz (Default) | 50 Hz
Total Harmonic Distortion Voltage <5%
Transfer Time 20ms (Default) | 10ms
(Configurable) | 20ms (Parallel)
PV INPUT
No. 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. Utilized PV Array Power:18 18000W
Max. Recommended PV Input 18000W
Max. Efficiency 97.5% (PV to Grid) | 94.5% (PV to Battery)
| 94% (Battery to Grid)
Idle Consumption <65W
BATTERY
Nominal Voltage 48VDC
Voltage Range 40 – 60VDC
Max. Charge / Discharge Power 10000W
Recommended Battery
Capacity per Inverter		 >300Ah
OPERATING ENVIRONMENT
Operating / Storage Temperature
Range		 -13ºF – 140ºF (-25ºC – 60ºC)
Operating Altitude <6,561 ft (2000 m)
Relative Humidity 0 – 100%
Typical Noise Emission <50dB @ 3 ft
Design Topology High-Frequency / Transformerless
Protection Rating IP65 / NEMA 4X
Communications RS485 / CANBus / WiFi / 4G
Max. Parallel Connections 10
DIMENSIONS
Weight 115 lbs
Depth 11.2 in
Width 22.8 in
Height 30.5 in

PACKAGE INCLUDES

BigBattery ETHOS 48V LifePO4 Batteries + EG4 FlexBOSS18 13kW 48V Hybrid Solar Inverter

BigBattery ETHOS 48V 5.12kWh Stackable Battery Module

x 2

BigBattery ETHOS Control Box

x 1

EG4 FlexBOSS18 13kW 48V Split Phase AC Hybrid Inverter

x 1

BigBattery 10kWh Ethos Controller to Battery Power Cable 31.5″ inch

x 1

Product Documents:

BigBattery ETHOS 48V 5.12kWh LiFePO4 Stackable Battery Module User Manual

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BigBattery ETHOS Control Box User Manual

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BigBattery ETHOS Control Box Specification Sheet

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EG4 13kW 48V Split Phase AC Hybrid Inverter User Manual

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EG4 FlexBOSS18 13kW 48V Split Phase AC Hybrid Inverter Specification Sheet

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EG4 FlexBOSS18 13kW 48V Split Phase AC Hybrid Inverter Certification Of Compliance

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