The EG4 FlexBOSS21 is a 48V split-phase hybrid inverter/charger built for whole-home backup and grid-tied solar systems that need serious continuous output and PV headroom. It's suited for homeowners and installers who want off-grid capability, grid interaction, and room to scale with parallel units.
This is a hybrid architecture unit: it operates off-grid, stays grid-connected for pass-through power, and interacts with the grid for sell-back, depending on your utility agreement and interconnection setup. The datasheet cites CSA C22.2#330:2017 and NEC 690.12 rapid-shutdown readiness for this design. Note: If you would like to review the manufacturer Product Specifications, Warranty, Brochure, etc., for this system, please refer to the "Resources (System Manuals and Warranty)" Tab above on this page.
Critical Power & Interconnection Requirements
- AC Output: 120/240 VAC or 120/208 VAC split-phase (L1/L2/N required), 50/60Hz, single-phase.
- Battery DC Input: 48V nominal (51.2 VDC), operating range 40-60 VDC. Max charge/discharge current: 250 ADC.
- Continuous Output: 16kW with PV & battery combined; 12kW continuous using battery alone.
- Surge/Peak Output (separate from continuous): 24000W for 0.5 sec, 18000W for 1 sec, 15000W for 6 min, 13200W for 12 min. Locked Rotor Amps: 195A.
- PV Input: 3 independent MPPTs, max recommended array 21kW (STC), max DC input voltage 600 VDC.
- Does NOT operate on 12V or 24V battery banks - 48V nominal architecture only.
- Does NOT include the optional EG4 FlexBOSS Screen Kit as standard - display is optional.
- Requires a battery firmware update for closed-loop communication with LifePower4 batteries specifically; not automatic out of the box.
Neutral-ground bonding is the friction point installers hit most often on split-phase hybrid units like the FlexBOSS21. If you bond neutral to ground both inside the inverter and at your main service panel, you create a parallel neutral path that trips GFCI protection intermittently and can cause nuisance fault codes months after commissioning - not just at startup. Verify bonding continuity with a Megohmmeter before energizing, and confirm only one bonding point exists in the system per NEC Article 690 and 706 grounding requirements for ESS equipment. This single check prevents the callback where a homeowner reports "random" inverter faults that only show up under specific load combinations.
Key Benefits
- Three independent MPPTs (26A / 26A / 15A rated) give granular control over solar string design and reduce clipping losses versus a single-tracker input.
- CEC weighted efficiency of 97%, with max PV-to-grid/load efficiency also at 97%.
- Configurable transfer time: 20ms default, adjustable down to 10ms, for grid-to-battery switching.
- Rapid Shutdown built-in, referenced against CSA C22.2#330:2017 and NEC 690.12.
- Remote connectivity via Wi-Fi (dongle included), Cellular, and Ethernet with mobile app monitoring and notifications.
- Parallels up to 16 units for a combined 256kW system output, suited for scaling whole-home or light commercial backup.
Technical Table
| Spec | Value | Unit |
|---|---|---|
| Type | Hybrid | - |
| Design Topology | High Frequency - Transformerless | - |
| AC Nominal Output Voltage | 120/240 or 120/208 (L1/L2/N required) | VAC |
| Frequency | 50/60 | Hz |
| Max Continuous Output (PV & Battery) | 66.7A / 16000 | A / W |
| Max Continuous Output (Battery Only) | 50A / 12000 | A / W |
| Peak Power (0.5 sec) | 24000 | W |
| Peak Power (1 sec) | 18000 | W |
| Peak Power (6 min) | 15000 | W |
| Peak Power (12 min) | 13200 | W |
| Locked Rotor Amps (LRA) | 195 | A |
| Max Apparent Power (Battery) | 12 | kVA |
| Max Apparent Power (PV & Grid) | 16 | kVA |
| Max Grid Input Power to Inverter | 50A / 12000 | A / W |
| Max Grid Pass-Thru Current | 90 | A |
| Battery Nominal Voltage | 51.2 | VDC |
| Battery Operating Voltage Range | 40 - 60 | VDC |
| Max Charge Current | 250 | ADC |
| Max Discharge Current | 250 | ADC |
| Recommended Min. Battery Capacity per Inverter | 600 | Ah |
| Number of MPPTs | 3 | - |
| Rated Current per MPPT | 26 (MPPT1) / 26 (MPPT2) / 15 (MPPT3) | A |
| Max DC Input Voltage | 600 | VDC |
| MPPT DC Startup Voltage | 200 | VDC |
| MPPT Full Power Voltage Range | 250 - 440 | VDC |
| MPPT DC Operating Voltage Range | 120 - 440 | VDC |
| MPPT Voltage High Protection | 550 | VDC |
| Recommended Max. Solar Array Power (STC) | 21 | kW |
| Response Transfer Time (Default / Configurable) | 20 / 10 | ms |
| CEC Weighted Efficiency | 97 | % |
| Idle Consumption (Standby, 25C) | <65 | W |
| Parallel Capability | Up to 16 units / 256 | units / kW |
| Dimensions | 22.28 x 30.43 x 11.22 | in. |
Note: See "Resources (System Manuals and Warranty)" Tab above for full specifications.
Compatibility & Fitment
- Compatible with EG4 48V batteries and other battery brands via closed-loop communications, per manufacturer datasheet.
- Closed-loop communication with LifePower4 batteries requires a battery firmware update - not plug-and-play without that update.
- Recommended minimum battery capacity per inverter: 600Ah.
- Interfaces with the EG4 GridBOSS MID for expanded Energy Storage System (ESS) control.
- NOT compatible with 12V or 24V battery banks - 48V nominal architecture only.
- Wi-Fi dongle is included by default; screen/display kit is optional and NOT included standard.
- Supports paralleling up to 16 units (256kW total); standalone units do not require paralleling to function.
Compliance & Environment
| Item | Detail |
|---|---|
| Rapid Shutdown | CSA C22.2#330:2017 and NEC 690.12 ready, built-in RSD capability |
| Model Number | IV-16000-HYB-AW-FX-XX (XX = 00-99) |
| CEC Model # | IV-16000-HYB-AW-FX-XX (240V) / IV-16000-HYB-AW-FX-XX (208V) |
| UL Listings | [NEEDS VERIFICATION - not stated in provided source data] |
| NEMA Rating | [NEEDS VERIFICATION - not stated in provided source data] |
FAQ
Can this inverter sell power back to the grid?
Yes. The FlexBOSS21 is a hybrid, all-in-one inverter capable of running off-grid, using grid electricity, and selling power back to the grid.
What battery voltage is required?
The FlexBOSS21 requires a 48V nominal battery bank, with an operating voltage range of 40-60 VDC. It is not compatible with 12V or 24V battery banks.
Can I parallel multiple units together?
Yes. The FlexBOSS21 can be paralleled up to 16 units for a combined total output of 256kW.
Is this UL 1741 listed for utility interconnection?
The manufacturer datasheet references CSA C22.2#330:2017 and NEC 690.12 readiness for rapid shutdown. UL 1741 listing status was not stated in the source specification sheet. [NEEDS VERIFICATION]
Is a Wi-Fi module included?
Yes, a plug-in Wi-Fi dongle is included by default, enabling remote monitoring through the EG4 app or EG4 Monitor system. Remote connectivity also supports Cellular and Ethernet.
Warranty & Registration
The manufacturer source material references a 10-year remote frequency adjustment warranty note for the FlexBOSS design. Warranty registration is completed through the EG4 Electronics website. For complete, current warranty terms specific to this unit, please refer to the "Resources (System Manuals and Warranty)" Tab above on this page.
