Product Summary:

The EG4 FlexBOSS18 Hybrid Inverter is a high-capacity, next-generation solution designed for residential and commercial energy systems. With up to 18,000W PV input and 13,000W split-phase (120/240V) output, it delivers powerful, flexible performance for both on-grid and off-grid energy systems.

 

Featuring dual MPPT inputs supporting multiple strings, the FlexBOSS18 maximizes solar production while efficiently managing energy from solar, battery, grid, and generator sources. With 90A grid feed-through, it supports high-demand loads and seamless system integration.

 

Designed to pair with the EG4 GridBOSS MID gateway, the system enables advanced energy control including smart load management, AC coupling, and generator support, while simplifying installation and reducing system costs. Built-in protections such as rapid shutdown, ground fault, and arc fault protection ensure safe and code-compliant operation.

With Wi-Fi connectivity, remote monitoring, and mobile alerts, the FlexBOSS18 provides full system visibility and control, making it a reliable, scalable solution for modern energy independence.

Ships From: Texas, USA
Warranty: 10 Years
Support: Lifetime USA-Based Tech Support

 

Compatibility

UL 9540 Certified + Closed-Loop Communication (Grid-Tied + Off Grid):

  • BigBattery ETHOS
  • EG4 Batteries

Power Compatibility:

  • Works with 48V battery systems
  • Supports grid-tied, hybrid, and off-grid installations
  • AC coupling compatible for system upgrades and retrofits
  • Integrates with EG4 GridBOSS MID for advanced system control

Key Features

  • 18,000W PV Input Capacity – High solar input for large residential and commercial systems
  • Split-Phase 120/240V Output – Powers both standard and heavy-duty loads
  • Dual MPPT Inputs – Optimizes solar production across multiple arrays
  • 90A Grid Feed-Through – Supports high-demand loads and seamless grid integration
  • GridBOSS Integration – Enables advanced load management, AC coupling, and generator support
  • Advanced Safety Protections – Includes rapid shutdown, ground fault, and arc fault protection
  • Smart Energy Management – Supports peak shaving and intelligent power distribution
  • Remote Monitoring & Alerts – Real-time system tracking via Wi-Fi and mobile app
  • Flexible System Design – Ideal for grid-tied, hybrid, and off-grid installations
  • Installer-Friendly Design – Reduces installation time and system complexity
  • Maintenance-Free Operation – No routine servicing required

A powerful, scalable hybrid inverter built for performance, flexibility, and advanced energy control in modern energy systems.

EG4 FlexBoss18 Inverter - easily scalable
UL Certified - EG4 FlexBoss18 Inverter
power stays on in rain and snow - EG4 FlexBoss18 Inverter
GridBoss
EG4 lineup

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Inverter Downloads

SKU#: INV031
Spec Sheet:DownloadDOWNLOAD
User Manual:DownloadDOWNLOAD
UL1741 Certificate:DownloadDOWNLOAD
CEC Listing- EG4 FlexBoss18: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:54A @ 240V | 54A @ 208V
Max. AC Input Power:13000W
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: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%
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:1818000W
Max. Recommended PV Input:18000W
Max. Efficiency:97.5% (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:10000W
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 / 4G
Max. Parallel Connections:10
Weight:115 lbs (52 kg)
Depth:11.2 in (287 mm)
Width:22.8 in (567 mm)
Height:30.5 in (775 mm)

Compare Inverter

10-Year EG4 Manufacturer Warranty

EG4 FlexBoss18 Inverter - easily scalable
UL Certified - EG4 FlexBoss18 Inverter
power stays on in rain and snow - EG4 FlexBoss18 Inverter
GridBoss
EG4 lineup

.

See More On YouTube

Inverter Downloads

SKU#: INV031
Spec Sheet:DownloadDOWNLOAD
User Manual:DownloadDOWNLOAD
UL1741 Certificate:DownloadDOWNLOAD
CEC Listing- EG4 FlexBoss18: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:54A @ 240V | 54A @ 208V
Max. AC Input Power:13000W
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: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%
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:1818000W
Max. Recommended PV Input:18000W
Max. Efficiency:97.5% (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:10000W
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 / 4G
Max. Parallel Connections:10
Weight:115 lbs (52 kg)
Depth:11.2 in (287 mm)
Width:22.8 in (567 mm)
Height:30.5 in (775 mm)

Compare Inverter

10-Year EG4 Manufacturer Warranty

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