EG4-WallMount Indoor Battery ESS | 48V 314Ah | 16kWh | UL9540 | EG4 FlexBOSS21 Hybrid Inverter | Grid-Tied System

SKU# K0210

Documents & Certifications

About this item

The EG4 314Ah Indoor Battery + EG4 FlexBOSS21 ESS System delivers smart power, simple reliability, and scalable energy independence for both on-grid and off-grid applications. Combining the high-capacity 16kWh EG4 WallMount Indoor LiFePO₄ battery with the advanced FlexBOSS21 hybrid inverter, this system provides dependable whole-home backup and efficient energy management in a clean, space-saving design.

 

The FlexBOSS21 delivers 12kW output and up to 21,000W PV input with 3 MPPTs, maximizing solar production and system flexibility. Paired with the EG4 314Ah battery – featuring 200A continuous output, 8,000+ cycle life, and third-generation BMS technology – this system ensures stable, high-performance energy delivery for residential and small commercial use.

 

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 between battery and inverter.

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

 

Compatibility

Integrated & Optimized System:

  • EG4 314Ah Indoor Battery + EG4 FlexBOSS21 Hybrid Inverter

Expandable & Flexible:

  • Cross-compatible with other EG4 battery systems
  • Scalable energy storage for growing system needs
  • Supports grid-tied, hybrid, and off-grid installations
Key Features
  • Complete ESS SolutionBattery + inverter system designed to work seamlessly together
  • 21,000W PV Input / 12kW OutputHigh-capacity power for residential and commercial systems
  • 16kWh LiFePO₄ Battery (314Ah)High-density, safe lithium storage
  • 200A Continuous Output / 12.8kW PeakPowers heavy household loads and backup systems
  • 8,000+ Cycle LifeLong-lasting performance at 80% DoD
  • Advanced 3rd-Gen BMSImproved monitoring, faster response, and precise balancing
  • Auto-ID TechnologySimplifies installation and system configuration
  • Self-Heating FunctionReliable performance in cold climates
  • Closed-Loop CommunicationSeamless coordination between battery and inverter
  • GridBOSS IntegrationAdvanced load management, AC coupling, and generator support
  • Wall or Floor Mount Design (IP20)Flexible, space-saving indoor installation
  • Maintenance-Free OperationNo routine servicing required

A high-capacity, intelligent energy storage system built for performance, flexibility, and long-term energy independence – with the reliability and control modern energy systems demand.

Introducing The EG4 WallMount Indoor Battery

Latest BMS Technology

Third-Generation BMS: Provides advanced monitoring, improved balancing precision, and faster response times for greater safety and system efficiency.

All-Weather Self-Heating

Self-Heating Function: Maintains optimal performance and battery health in cold environments.

Your Personal Power House

200A Continuous Output / 12.8kW Peak Power: Supports heavy household loads and seamless backup operation.

Show off your build!

Community sparks inspiration, if you’d like to take pride in presenting your set up, submit your build to us for a chance to be featured and win a BigBattery mystery gift. Enter your build here.

Key Features:

  • Cross-Compatible with Other EG4 Models: Seamlessly integrates with existing
    EG4 battery systems for flexible scaling and expanded storage capacity. (Note: UL9540 Certified only with Flexboss 18 & Flexboss 21)
  • Hybrid Wall or Floor Mount Design: Flexible installation options with a durable,
    space-saving enclosure (IP20 rated).
  • High-Capacity Storage: 16kWh nominal energy and 314Ah capacity for
    reliable, high-output performance.
  • Auto-ID Technology: Automatically recognizes and syncs new batteries during
    installation, simplifying system setup and configuration.

Battery Downloads

SKU#:FEWMT-48161-G1
Spec Sheet:DownloadDOWNLOAD
User Manual:DownloadDOWNLOAD
Quick Start Guide:DownloadDOWNLOAD
Certification of Compliance:DownloadDOWNLOAD
Certification of Conformity:DownloadDOWNLOAD
DC ESS UL-9540 Certification:DownloadDOWNLOAD

Battery Specifications

Product Type:Low Voltage LFP Battery
Battery Type:Lithium Iron Phosphate (LFP)
Model Number:WM-48-314-IN-XX (XX is a number between 00 – 99)
Nominal Energy Capacity:16kWh
Usable Energy (DOD%):12.86kWh (80% recommended)
Voltage Range:47.5 – 57.6 VDC
Nominal Voltage:51.2 VDC
Capacity:314Ah
Charging Voltage Range:56 – 57 VDC
Discharging Cut-off Voltage:47.5 VDC
Max Continuous Charge Current:157A
Max Continuous Discharge Current:200A
Continuous Charge/Discharge Power:8/10.2 kW
Recommended Charging/Discharging Rate:0.5C
Peak Power:12.8kW (3 sec)
Round-trip Efficiency:95%
Max Parallel Units:16
Protection Features:Over/Under Voltage, Over-Current, Short Circuit, High/Low Temp
Battery Management System (BMS):Integrated, Active Balancing
Communication Protocols:RS485, CAN
Battery Breaker:250A
Storage Temperature Range**:-4 – 131°F (-20 – 55°C)
Humidity Range:5% – 95% RH (non-condensing)
Altitude:9843 ft. (<3000 m)
Cooling Method:Natural Convection
Dimensions (H × W × D):34.1 in. × 18.1 in. × 9.6 in. (865 mm × 460 mm × 245 mm)
Operating Temperature Range:Charge: 32 – 122°F (0 – 50°C); Discharging: -4 – 131°F (-20 – 55°C)
Recommended DOD Setting Note*:EG4 recommends this value be set no lower than 20% to maintain the recommended 80% Depth of Discharge.
Storage Temperature Note**:Less than 3 months of storage. If longer than 3 months, recommended storage temperature will be 59°F – 86°F (15°C – 30°C).
Weight:293.2 lbs. (133 kg)
Enclosure Rating:IP20
Mounting Options:Wall/Floor mount
Display/Indicators:LED Status
Connector Type:Degson quick connector/screw terminal
UL 1973:Yes
UL 9540:DC ESS, AC ESS with EG4 18kPV, 12kPV, FlexBOSS 21, FlexBOSS 18*
UL 9540A:Batt to Batt spacing of 6 in.
UN 38.3:Yes
FCC Part 15 (EMC):Yes
Protection Class:Class B
Cycle Life (70% EOL Capacity):10000 cycles @ 0.5C, 25°C, 80% DOD
Design Life*:10 years
Warranty:10 years or 10000 cycles
Application Type:Residential/Commercial/Off-grid/Backup
Lifetime Energy Throughput (Calculated):(51.2V×314Ah/1000×80%×10000/1000)90% = 115.7 MWh or (12861 kWh×10000 cycles×90% efficiency) = 115.7 MWh
Note:Information subject to change without notice.

 

Inverter Downloads

SKU#:INV027
Spec Sheet:DownloadDOWNLOAD
User Manual:DownloadDOWNLOAD
UL1741 Certificate:DownloadDOWNLOAD
CEC Listing- EG4 FlexBoss21:Go to linkGO TO LINK

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)

EG4 WallMount Indoor Battery: 10-Year EG4 Manufacturer Warranty

Introducing The EG4 WallMount Indoor Battery

Latest BMS Technology

Third-Generation BMS: Provides advanced monitoring, improved balancing precision, and faster response times for greater safety and system efficiency.

All-Weather Self-Heating

Self-Heating Function: Maintains optimal performance and battery health in cold environments.

Your Personal Power House

200A Continuous Output / 12.8kW Peak Power: Supports heavy household loads and seamless backup operation.

Show off your build!

Community sparks inspiration, if you’d like to take pride in presenting your set up, submit your build to us for a chance to be featured and win a BigBattery mystery gift. Enter your build here.

Key Features:

  • Cross-Compatible with Other EG4 Models: Seamlessly integrates with existing
    EG4 battery systems for flexible scaling and expanded storage capacity. (Note: UL9540 Certified only with Flexboss 18 & Flexboss 21)
  • Hybrid Wall or Floor Mount Design: Flexible installation options with a durable,
    space-saving enclosure (IP20 rated).
  • High-Capacity Storage: 16kWh nominal energy and 314Ah capacity for
    reliable, high-output performance.
  • Auto-ID Technology: Automatically recognizes and syncs new batteries during
    installation, simplifying system setup and configuration.

Battery Downloads

SKU#:FEWMT-48161-G1
Spec Sheet:DownloadDOWNLOAD
User Manual:DownloadDOWNLOAD
Quick Start Guide:DownloadDOWNLOAD
Certification of Compliance:DownloadDOWNLOAD
Certification of Conformity:DownloadDOWNLOAD
DC ESS UL-9540 Certification:DownloadDOWNLOAD

Battery Specifications

Product Type:Low Voltage LFP Battery
Battery Type:Lithium Iron Phosphate (LFP)
Model Number:WM-48-314-IN-XX (XX is a number between 00 – 99)
Nominal Energy Capacity:16kWh
Usable Energy (DOD%):12.86kWh (80% recommended)
Voltage Range:47.5 – 57.6 VDC
Nominal Voltage:51.2 VDC
Capacity:314Ah
Charging Voltage Range:56 – 57 VDC
Discharging Cut-off Voltage:47.5 VDC
Max Continuous Charge Current:157A
Max Continuous Discharge Current:200A
Continuous Charge/Discharge Power:8/10.2 kW
Recommended Charging/Discharging Rate:0.5C
Peak Power:12.8kW (3 sec)
Round-trip Efficiency:95%
Max Parallel Units:16
Protection Features:Over/Under Voltage, Over-Current, Short Circuit, High/Low Temp
Battery Management System (BMS):Integrated, Active Balancing
Communication Protocols:RS485, CAN
Battery Breaker:250A
Storage Temperature Range**:-4 – 131°F (-20 – 55°C)
Humidity Range:5% – 95% RH (non-condensing)
Altitude:9843 ft. (<3000 m)
Cooling Method:Natural Convection
Dimensions (H × W × D):34.1 in. × 18.1 in. × 9.6 in. (865 mm × 460 mm × 245 mm)
Operating Temperature Range:Charge: 32 – 122°F (0 – 50°C); Discharging: -4 – 131°F (-20 – 55°C)
Recommended DOD Setting Note*:EG4 recommends this value be set no lower than 20% to maintain the recommended 80% Depth of Discharge.
Storage Temperature Note**:Less than 3 months of storage. If longer than 3 months, recommended storage temperature will be 59°F – 86°F (15°C – 30°C).
Weight:293.2 lbs. (133 kg)
Enclosure Rating:IP20
Mounting Options:Wall/Floor mount
Display/Indicators:LED Status
Connector Type:Degson quick connector/screw terminal
UL 1973:Yes
UL 9540:DC ESS, AC ESS with EG4 18kPV, 12kPV, FlexBOSS 21, FlexBOSS 18*
UL 9540A:Batt to Batt spacing of 6 in.
UN 38.3:Yes
FCC Part 15 (EMC):Yes
Protection Class:Class B
Cycle Life (70% EOL Capacity):10000 cycles @ 0.5C, 25°C, 80% DOD
Design Life*:10 years
Warranty:10 years or 10000 cycles
Application Type:Residential/Commercial/Off-grid/Backup
Lifetime Energy Throughput (Calculated):(51.2V×314Ah/1000×80%×10000/1000)90% = 115.7 MWh or (12861 kWh×10000 cycles×90% efficiency) = 115.7 MWh
Note:Information subject to change without notice.

 

Inverter Downloads

SKU#:INV027
Spec Sheet:DownloadDOWNLOAD
User Manual:DownloadDOWNLOAD
UL1741 Certificate:DownloadDOWNLOAD
CEC Listing- EG4 FlexBoss21:Go to linkGO TO LINK

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)

EG4 WallMount Indoor Battery: 10-Year EG4 Manufacturer Warranty

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