Product Summary:
The EG4 280Ah All-Weather Battery + EG4 FlexBOSS21 ESS System is a powerful, all-in-one energy solution designed for both on-grid and off-grid applications. Combining the rugged 14.3kWh EG4 All-Weather LiFePO₄ battery with the high-performance FlexBOSS21 hybrid inverter, this system delivers reliable, 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 system flexibility. Paired with the durable All-Weather battery – featuring 8,000+ cycle life, integrated self-heating, and advanced safety protections – this system is built to perform in demanding environments.
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 280Ah All-Weather 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 – High solar capacity with 3 MPPTs for maximum efficiency
- 12kW Output Power – Supports residential and light commercial loads
- 14.3kWh LiFePO₄ Battery – Durable, high-capacity energy storage
- 8,000+ Cycle Life – Long-lasting performance at 80% DoD
- All-Weather Design – Built for reliable operation in indoor and outdoor environments
- Integrated Self-Heating – Reliable performance in cold climates
- Advanced BMS & Safety Protections – Includes EMP protection, fire safety features, and system safeguards
- Smart Energy Management – Supports load control, AC coupling, and generator integration
- Remote Monitoring & Alerts – Real-time system tracking and control
- Maintenance-Free Operation – No routine servicing required
A durable, high-performance energy storage system built for flexibility, resilience, and long-term energy independence.
EG4 Wallmount All Weather Battery & FlexBoss21 Hybrid Inverter (ESS) | 14.3-85.8kWh | UL9540 | Grid-Tied Home Solar System (21kW-63kW PV)
YOU SAVED: $600.00
SKU# K0100
Battery Selected
1× EG4 All Weather
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
3x Inverter
3 Phase
Quantity:
.
See More On YouTube
Battery Downloads
Battery Specifications
Nominal Voltage:51.2V
Chemistry:Lithium Iron Phosphate (LiFePO4)
kWh Capacity:14.3kWh
Ah Capacity:280Ah
BMS Charging Voltage (Bulk/Absorb):56.0V (±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 Current:140A
Max. Continuous Discharge Current:140A (200A Max. Continuous for 30 min)
Rec. Charge Current:60 – 140A
Rec. Discharge Current:60 – 140A
Max Continuous Discharge Rate:10,240W
Voltage:56V
Power Consumption:224W
Internal Temperature Cutoffs:≤32ºF (On) | ≥41ºF (Off)
Charging Temperature Range:32ºF – 122ºF (0ºC – 50ºC)
Discharging Temperature Range:-4ºF – 131ºF (-20ºC – 55ºC)
Storage Temperature Range:32ºF – 113ºF (0ºC – 45ºC)
Operating Altitude:<16,404 ft (<5,000 m)
Protection Rating:IP65
Communications:RS485 | CANBus
Weight:308.6 lbs (140 kg)
Depth:9.1 in (232 mm)
Width:22.3 in (566 mm)
Height:36.1 in (916 mm)
Inverter Downloads
SKU#:K0100
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
EG4 FlexBoss21 Inverter: 10-Year EG4 Manufacturer Warranty
EG4 All Weather Battery: 10-Year EG4 Manufacturer Warranty
.
See More On YouTube
Battery Downloads
Battery Specifications
Nominal Voltage:51.2V
Chemistry:Lithium Iron Phosphate (LiFePO4)
kWh Capacity:14.3kWh
Ah Capacity:280Ah
BMS Charging Voltage (Bulk/Absorb):56.0V (±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 Current:140A
Max. Continuous Discharge Current:140A (200A Max. Continuous for 30 min)
Rec. Charge Current:60 – 140A
Rec. Discharge Current:60 – 140A
Max Continuous Discharge Rate:10,240W
Voltage:56V
Power Consumption:224W
Internal Temperature Cutoffs:≤32ºF (On) | ≥41ºF (Off)
Charging Temperature Range:32ºF – 122ºF (0ºC – 50ºC)
Discharging Temperature Range:-4ºF – 131ºF (-20ºC – 55ºC)
Storage Temperature Range:32ºF – 113ºF (0ºC – 45ºC)
Operating Altitude:<16,404 ft (<5,000 m)
Protection Rating:IP65
Communications:RS485 | CANBus
Weight:308.6 lbs (140 kg)
Depth:9.1 in (232 mm)
Width:22.3 in (566 mm)
Height:36.1 in (916 mm)
Inverter Downloads
SKU#:K0100
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
EG4 FlexBoss21 Inverter: 10-Year EG4 Manufacturer Warranty
EG4 All Weather Battery: 10-Year EG4 Manufacturer Warranty
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