EG4 FlexBOSS21 All-in-One Hybrid Inverter | 21kW PV Input | 48V Split Phase
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Visit CalculatorThe EG4 FlexBOSS21 hybrid solar inverter is a flexible 48V split-phase inverter/charger that delivers the reliable power of the 18kPV with added adaptability. It is powerful enough to start a 5-ton AC unit and supports 21kW of PV input. With the ability to parallel up to 10 units, the FlexBOSS21 achieves an impressive total continuous output of 160kW using PV input. Equipped with three MPPTs, it provides optimal solar management, while the enhanced EG4 monitoring software offers complete remote control, including mobile alerts and remote settings adjustments. Its integration with GridBOSS ensures comprehensive management of the entire Energy Storage System (ESS).
The FlexBOSS21 blends efficiency, durability, and innovation, making it an excellent option for those in need of reliable energy solutions. With advanced monitoring and safety features, it delivers dependable power and assurance for both residential and commercial installations. Go off-grid, stay connected, or sell back to the grid. The choice is yours.


Everything you need is included with your product.
| Specification | Details |
| Input Voltage Range | 120/240VAC; 120/208VAC (Split-phase) |
| Output Power | 16kW continuous when using pv input, with a peak surge capacity of 24kW |
| Dimensions | 29.5 x 20.5 x 11.2 inches |
| Weight | 88 lbs |
| Warranty | 10-year standard warranty, covering all major components |
Can the EG4 FlexBOSS21 operate both off-grid and grid-tied?
Yes! The FlexBOSS21 is designed for off-grid energy independence, grid-tied integration, and hybrid operation with battery backup.
What battery types are compatible with this inverter?
This inverter is optimized for 48V LiFePO4 battery banks, ensuring efficient and long-lasting performance.
Can I expand my system with additional inverters?
Yes, the FlexBOSS21 supports parallel operation, allowing multiple units to be stacked for increased energy output.
Does it support remote monitoring?
Yes! The Wi-Fi and RS485 connectivity allow real-time system monitoring and control via the EG4 app.
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I was a DIY solar power wannabe... that is 'til I connected with Manny... The man's a prince! He not only knows his stuff; he walked me through all things electrical. To make sure I had all I needed... he gave me his cell phone # to text him anytime I got confused... nights and weekends included. The prices were very competitive... definitely go with Manny -- you won't go wrong!
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