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EG4 FlexBOSS21 Complete Power System

EG4 FlexBOSS21 Complete Power System

BY: EG4 | SKU: EG4-WM48x1-CB1 Availability: In Stock
$9,834.86

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EG4 FlexBOSS21 Complete Power System

The EG4 FlexBOSS21 Complete Power System is a powerful all-in-one hybrid energy solution that combines the EG4 FlexBOSS21 16kW Hybrid Inverter, EG4 48V 280Ah Lithium Batteries (indoor or all-weather outdoor), and the EG4 GridBOSS 200A MID for seamless home or business energy control.

Designed for reliability, scalability, and efficiency, this system provides 21kW solar input, split-phase 120/240V output, and intelligent grid-to-battery management—perfect for both off-grid and grid-tied setups.

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EG4 FlexBOSS21 Complete Power System Features

All-in-One Hybrid Power System - Streamlined design integrates inverter, charger, and controller for simplified setup and seamless energy conversion between solar, grid, and batteries.

21kW Solar Input Capacity - Connect up to 21,000W of PV solar, maximizing renewable energy generation for high-demand applications.

Flexible Battery Options - Choose between EG4 WallMount Indoor Batteries or EG4 PowerPro All-Weather Batteries, each rated 48V 280Ah (14.3kWh) and built with LiFePO₄ chemistry for over 6,000 charge cycles.

GridBOSS 200A MID Integration - The included EG4 GridBOSS 200A MID provides automatic load transfer, full home integration, and safe, code-compliant switching between grid and battery power.

Whole-Home Power Management - Supports 120V and 240V split-phase output to run heavy-duty appliances like HVAC systems, pumps, and EV chargers.

Smart Monitoring & Control - Monitor, control, and optimize your energy system via advanced software and mobile app connectivity (Wi-Fi/CAN/RS485).

Expandable & Future-Ready - Easily scale up with additional inverters and batteries to meet evolving energy needs for off-grid homes or commercial setups.

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EG4 FlexBOSS21 Complete Power System Applications

  • Whole-Home Backup – Seamless power during grid outages.
  • Off-Grid Living – Complete energy independence for remote homes or cabins.
  • Commercial Facilities – Reliable backup for offices, farms, or warehouses.
  • Solar + Storage Systems – Efficient renewable energy management.
  • RV or Outbuilding Power – Compact yet powerful setup for remote installations.
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What's Included

Everything you need is included with your product.

Indoor Power System Kit Includes:

  • (1) EG4 FlexBOSS21 16kW (21kPV) All-in-One Hybrid Inverter
  • (1–2) EG4 WallMount Indoor Battery 280Ah (14.3kWh each)
  • (1–2) EG4 Indoor Buildable Conduit Boxes
  • (1) EG4 GridBOSS 200A MID (Included)
  • User Manual

Outdoor Power System Kit Includes:

  • (1) EG4 FlexBOSS21 16kW (21kPV) All-in-One Hybrid Inverter
  • (1–2) EG4 PowerPro 48V 280Ah All-Weather Batteries (14.3kWh each)
  • (1–2) EG4 PowerPro Conduit Boxes
  • (1) EG4 GridBOSS 200A MID (Included)
  • User Manual

EG4 FlexBOSS21 Specifications

Specification Details
Compatible Battery Types Lead-acid/ Lithium
Max. Charge/Discharge Power 12000W
Nominal Voltage 48VDC
Voltage Range 40 – 60 VDC
Recommended Battery Capacity Per Inverter >300Ah
Max Units in Parallel 16
Product Dimensions (HxWxD) 30.43 × 22.28 × 11.22 in. (750 × 520 × 285 mm)
Unit Weight 88 lbs. (52 kg)
Design Topology High Frequency – Transformerless
Relative Humidity 0 – 100%
Operating Altitude <6561 ft (<2000 m)
Operating Ambient Temperature Range -13° – 140°F (-25° – 60°C)
Storage Ambient Temperature Range -13° – 140°F (-25° – 60°C)
Noise Emission (Typical) <50dB @ 3 ft
Communication Interface RS485/Wi-Fi/CAN
Standard Warranty 10-year standard warranty*
Outdoor Rating NEMA 4X

EG4 WallMount Indoor Battery Specifications

Specification Details
Voltage 51.2V
Total Energy Capacity 14.3kWh
Capacity 280Ah
Charging Voltage (Bulk/Absorb) 56.0V (+/-0.8V) to 56.2V (+/-0.2V)
Float Voltage 54V (+/-0.2V)
Low DC Cutoff 44.8V (adjustable start from 47V to 45.6V)
Charging Current Up to 200A (continuous), recommended range: 60A - 160A
Discharging Current Up to 200A (continuous), recommended: 160A
Communication Ports RS485/CAN Can be customized
Cycle Life >8000 Cycles, 80% Depth of Discharge (DOD)
Design Life Over 15 Years
Weight 282.2 lbs. (128 kg)
Safety Certifications UL1973, UL 9540A (Testing)

EG4 PowerPro WallMount AllWeather Lithium Battery Specifications

Specification Details
Battery Type LiFePO4 (Lithium Iron Phosphate, Grade A)
Voltage 48V (Nominal: 51.2V, Float: 54V)
Continuous Charge/Discharge Current 200A (Max)
Capacity 14.3kWh
BMS 200A
Weight 308.6 lbs. / 140Kg

EG4 GridBOSS Specifications

Specification Details
Communication Interface RS485/Wi-Fi/CAN
Internal Bus Rating 350A
Internal Fuse Rating 315A
Operating Altitude <6561 ft (<2000 m)
Relative Humidity 0 – 100%
Outdoor Rating NEMA 3R
Operating Ambient Temperature Range -40°F – 140°F (-40°C – 60°C)
Product Dimensions (HxWxD) 31.5×19.7×7 in (800×500×178 mm)
Unit Weight 55 lbs. (25 kg)
Standard Warranty 10-year standard warranty

Frequently-Asked Questions

Can this system power my entire home?

Yes, with 16kW output and split-phase 240V support, it can power all major appliances, HVAC units, and essential circuits.

What’s the main difference between the indoor and outdoor kits?

The Indoor Kit includes WallMount batteries for climate-controlled environments, while the Outdoor Kit includes IP65-rated PowerPro batteries for weatherproof performance.

Is the EG4 GridBOSS 200A MID included?

Yes, every kit includes the EG4 GridBOSS 200A MID for seamless home grid integration and load management.

Can I expand the battery capacity later?

Absolutely. The FlexBOSS21 supports multiple battery and inverter expansions.

Does it require professional installation?

Yes. Installation should be performed by a licensed electrician or certified installer for safety and compliance.