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BigBattery ETHOS + EG4 FLEXBOSS21 ESS

BigBattery ETHOS + EG4 FLEXBOSS21 ESS

$6,460.00 USD
$7,275.00 USD $6,460.00 USD
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Choose Your ESS Configuration

BigBattery ETHOS + EG4 FLEXBOSS21 ESS

Product Summary:

The BigBattery ETHOS™ + EG4 FlexBOSS21 ESS System is a complete, next-generation energy solution designed for both on-grid and off-grid applications. Combining the scalable ETHOS 48V lithium battery system with the powerful FlexBOSS21 hybrid inverter, this system delivers advanced, efficient, and intelligent energy management in one integrated package.

Expandable up to 80+ kWh, the ETHOS battery grows with your energy needs – while the FlexBOSS21 delivers 12kW output and up to 21,000W PV input with 3 MPPTs for maximum solar optimization. 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.

Ships From: Texas, USA
Warranty: 12 Years (Battery), 10 Years (Inverter)
Support: Lifetime USA-Based Tech Support

Compatibility

Integrated & Optimized System:

  • ETHOS Battery System + EG4 FlexBOSS21 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
  • 21,000W PV Input – High solar capacity with 3 MPPTs for maximum efficiency
  • 12kW Output Power – Supports residential and light commercial loads
  • 120/240V Split-Phase Output – Reliable power for whole-home applications
  • 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 powerful, future-ready energy storage system built for flexibility, performance, and long-term independence – backed by advanced controls, safety, and U.S.-based support.

Kit includes- Quantities depends on ESS Configuration

BigBattery ETHOS | 48V - 5.1kWh | UL1973 | Home Battery Backup LFP

ETHOS Control Box
EG4 FlexBOSS21 Hybrid Solar Inverter | 21kW PV / 16kW AC | Split-Phase | 4-MPPT | Scalable | Remote Wi-Fi Monitoring
0kWh Ethos Controller to Battery Power Cable 31.5\\\\\\\" inch (800mm)
Downloads & Specifications

Battery Specifications

GTIN-12 (U.P.C.):850061252005
System Voltage:48V
Nominal Voltage:51.2V
Chemistry:LiFePO4
kWh Capacity:10.24kWh
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:10240W
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)
Depth:6.7 in (170 mm)
Width:26.5 in (674 mm)
Height:43.3 in (1100 mm)
Max Connections:Up to (16) parallel connections per control box
Protection Rating:IP65 / NEMA 4X
Communications:CANBus / RS485
Certifications:UL9540, UL9540A, UL1973, & UN38.3

Inverter Specifications

Nominal AC Voltage:120/240VAC | 120/208VAC (L1/L2/N required)
Frequency:60 Hz (Default) | 50 Hz
Max. AC Current:50A @ 240V | 57.7A @ 208V
Max. AC Input Power:12000W
Max. AC Bypass:90A
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)
Rated Output Current:50A @ 240V | 57.7A @ 208V
Nominal Output Voltage:120/240VAC | 120/208VAC
Rated Output Power:12000W @ 240VAC | 12000W @ 208VAC
Peak Power:24000W (0.5 sec) | 18000W (1 sec)
15000W (6 min) | 13200W (12 min)
Operating Frequency:60 Hz (Default) | 50 Hz
Total Harmonic Distortion Voltage:<5%
Transfer Time:20ms (Default) | 10ms (Configurable) | 20ms (Parallel)
No. of MPPTs:3
Inputs per MPPT:2 (MPPT 1) | 2 (MPPT 2) | 1 (MPPT 3)
Max. Usable Input Current:26A (MPPT 1) | 26A (MPPT 2) | 15A (MPPT 3)
Max. Short Circuit Input Current:31A (MPPT 1) | 31A (MPPT 2) | 19A (MPPT 3)
DC Input Voltage Range:100 – 600VDC
Unit Start-Up Voltage:100VDC
MPPT Operating Voltage Range:120 – 440VDC
Nominal MPPT Voltage:360VDC
Max. Utilized PV Array Power:21000W
Max. Recommended PV Input:25000W
Max. Efficiency:97% (PV to Grid) | 94.5% (PV to Battery) | 94% (Battery to Grid)
Idle Consumption:<65W
Nominal Voltage:48VDC
Voltage Range:40 – 60VDC
Max. Charge / Discharge Power:12000W
Recommended Battery Capacity per Inverter:>300Ah
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
Max. Parallel Connections:16
Weight:88 lbs (40 kg)
Depth:11.3 in (287 mm)
Width:22.3 in (567 mm)
Height:30.5 in (775 mm)

Battery Downloads

SKU#:K0241, K0242, K0243, K0244, K0245, K0246, K0247, K0248, K0249, K0250, K0251
Spec Sheet:DownloadDOWNLOAD
User Manual:DownloadDOWNLOAD
UL9540 Certificate – BigBattery ETHOS + EG4 FlexBOSS21:DownloadDOWNLOAD
UL9540A Certificate:DownloadDOWNLOAD
UL1973 Certificate:DownloadDOWNLOAD
UN38.3 Certificate:DownloadDOWNLOAD
Safety Data Sheet:DownloadDOWNLOAD
CEC Listing – BigBattery ETHOS + EG4 FlexBOSS21:Go to linkGO TO LINK

Inverter Downloads

SKU#:K0241, K0242, K0243, K0244, K0245, K0246, K0247, K0248, K0249, K0250, K0251
Spec Sheet:DownloadDOWNLOAD
User Manual:DownloadDOWNLOAD
UL1741 Certificate:DownloadDOWNLOAD
CEC Listing – BigBattery ETHOS + EG4 FlexBOSS21:Go to linkGO TO LINK

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