Product Summary:
The EG4 280Ah Indoor Battery + EG4 FlexBOSS21 ESS System is a powerful, next-generation energy solution designed for both on-grid and off-grid applications. Combining the 14.3kWh EG4 WallMount Indoor LiFePO₄ battery with the advanced FlexBOSS21 hybrid inverter, this system delivers efficient, scalable, and intelligent energy management for residential and commercial use.
The FlexBOSS21 provides 12kW output and up to 21,000W PV input with 3 MPPTs, enabling maximum solar production and flexible system design. Paired with the indoor WallMount battery – featuring UL-certified LiFePO₄ storage, 8,000+ cycle life, advanced BMS protection, self-heating, and emergency stop capability – this system ensures safe, long-lasting performance.
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: 10 Years (Battery), 10 Years (Inverter)
Support: Lifetime USA-Based Tech Support
Compatibility
Integrated & Optimized System:
- EG4 280Ah Indoor Battery + EG4 FlexBOSS21 Hybrid Inverter
Expandable & Flexible:
- Add additional batteries for increased storage capacity
- Supports grid-tied, hybrid, and off-grid installations
- Compatible with solar + generator input configurations
Key Features
- Complete ESS Solution – Battery + inverter system designed to work seamlessly together
- 21,000W PV Input / 12kW Output – High-capacity power for residential and commercial systems
- 3 MPPT Inputs – Maximizes solar production across multiple arrays
- 14.3kWh LiFePO₄ Battery – Safe, UL-certified indoor energy storage
- 8,000+ Cycle Life – Long-lasting performance at 80% DoD
- Advanced BMS & Safety Features – Includes real-time monitoring, self-heating, and E-Stop
- GridBOSS Integration – Advanced load management, AC coupling, and generator support
- Closed-Loop Communication – Seamless coordination between battery and inverter
- Advanced Safety Protections – Includes rapid shutdown, ground fault, and arc fault protection
- Remote Monitoring & Alerts – Real-time system tracking and performance insights
- Wall-Mount Indoor Design – Clean, space-saving installation
- Maintenance-Free Operation – No routine servicing required
A powerful, future-ready energy storage system built for flexibility, safety, and long-term energy independence.
EG4 Wallmount 280Ah Indoor Battery & FlexBoss21 Hybrid Inverter (ESS) | 14.3-57.2kWh | UL9540 | Grid-Tied Home Solar System (21kW-42kW PV)
YOU SAVED: $600.00
SKU# K0106
Battery Selected
1× EG4 280Ah Indoor
Total Capacity
14.3 kWh
Inverter Selected
1× EG4 FlexBOSS21
Input / Output
21 kW / 16 kW
Choose Your ESS Configuration*
1x Inverter
Standard
2x Inverter
Large
Quantity:
.
See More On YouTube
Battery Downloads
Battery Specifications
System Voltage:48V
Nominal Voltage:51.2V
Chemistry:LiFePO4
kWh Capacity:14.3kWh
Ah Capacity:280Ah
BMS Charging Voltage (Bulk/Absorb):56V (±0.8V)
Rec. Charging Voltage (Bulk/Absorb):56.2V (±0.2V)
Rec. Float Setting:54V (±0.2V)
Rec. SoC Cutoff Setting:20%
Max. Continuous Charge/Discharge Current:200A
Rec. Charge Current:60 – 160A
Rec. Discharge Current:160A
Max Continuous Discharge Rate:10240W
Voltage:56V
Power Consumption:224W
Internal Temperature Cutoffs:≤32ºF (On) | ≥41ºF (Off)
Charging Temperature Range:32ºF – 113ºF (0ºC – 45ºC)
Discharging Temperature Range:-4ºF – 122ºF (-20ºC – 50ºC)
Storage Temperature Range:-4ºF – 122ºF (-20ºC – 50ºC)
Protection Rating:IP20
Communications:RS485 | CANBus
Weight:282.2 lbs (128 kg)
Depth:9.6 in (245 mm)
Width:18.1 in (460 mm)
Height:36.4 in (925 mm)
Inverter Downloads
SKU#:K0106
Spec Sheet:
DOWNLOAD
DOWNLOADUser Manual:DOWNLOAD
DOWNLOADUL1741 Certificate:DOWNLOAD
DOWNLOADCEC Listing- EG4 FlexBoss21:
GO TO LINK
GO TO LINKInverter 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)
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)
Compare Battery & Inverter
FlexBoss21 Inverter: 10-Year EG4 Manufacturer Warranty
WallMount Indoor Battery: 10-Year EG4 Manufacturer Warranty
.
See More On YouTube
Battery Downloads
Battery Specifications
System Voltage:48V
Nominal Voltage:51.2V
Chemistry:LiFePO4
kWh Capacity:14.3kWh
Ah Capacity:280Ah
BMS Charging Voltage (Bulk/Absorb):56V (±0.8V)
Rec. Charging Voltage (Bulk/Absorb):56.2V (±0.2V)
Rec. Float Setting:54V (±0.2V)
Rec. SoC Cutoff Setting:20%
Max. Continuous Charge/Discharge Current:200A
Rec. Charge Current:60 – 160A
Rec. Discharge Current:160A
Max Continuous Discharge Rate:10240W
Voltage:56V
Power Consumption:224W
Internal Temperature Cutoffs:≤32ºF (On) | ≥41ºF (Off)
Charging Temperature Range:32ºF – 113ºF (0ºC – 45ºC)
Discharging Temperature Range:-4ºF – 122ºF (-20ºC – 50ºC)
Storage Temperature Range:-4ºF – 122ºF (-20ºC – 50ºC)
Protection Rating:IP20
Communications:RS485 | CANBus
Weight:282.2 lbs (128 kg)
Depth:9.6 in (245 mm)
Width:18.1 in (460 mm)
Height:36.4 in (925 mm)
Inverter Downloads
SKU#:K0106
Spec Sheet:DOWNLOAD
DOWNLOADUser Manual:DOWNLOAD
DOWNLOADUL1741 Certificate:DOWNLOAD
DOWNLOADCEC Listing- EG4 FlexBoss21:GO TO LINK
GO TO LINKInverter 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)
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)
Compare Battery & Inverter
FlexBoss21 Inverter: 10-Year EG4 Manufacturer Warranty
WallMount Indoor Battery: 10-Year EG4 Manufacturer Warranty
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