Big Battery EG4 FlexBOSS18 13kW (18kPV) Hybrid Inverter - INV031
The latest development from the EG4 team, the FlexBOSS18 is a cutting-edge, split-phase hybrid inverter designed to be the keystone of any residential or commercial power system. With an incredible 18kW PV input capacity and an array of advanced features, the FlexBOSS18 provides reliable performance day in and day out, in both on-grid and off-grid settings.
The FlexBOSS18 is one of the highest capacity inverters on the market today, featuring 2 MPPTs supporting up to 4 strings, providing superior flexibility for multi-orientation solar arrays, and the ability to handle 90A of grid feed-through at 120/240VAC, ensuring robust grid-tied capabilities. Plus, the FlexBOSS18 seamlessly integrates with EG4’s GridBOSS MID power gateway for a cost-effective, streamlined setup, helping to reduce installation time and system startup costs, and when you pair these two units together in your system, you’re able to utilize the smart load management, AC coupling, and generator support features if needed.
But that’s not all. EG4 understands the value of enhanced safety and visibility when it comes to your power, and the FlexBOSS18 spares no expense, coming equipped with responsive rapid shutdown, ground fault monitoring, and arc fault protection, all backed by industry-leading safety certifications, and with EG4’s updated monitoring software, you get access to remote management, mobile notifications, and convenient Wi-Fi connectivity for your system.
Combining efficiency, scalability, and cutting-edge technology, the FlexBOSS18 is a top-tier solution, with a safety-first design, for those seeking a reliable, powerful inverter to anchor their energy system. Whether for residential or commercial applications, its advanced features and versatile design provide unmatched value and peace of mind. Elevate your energy independence and power your future with the EG4 FlexBOSS18 Hybrid Inverter today.
Specifications
| Nominal AC Voltage |
120/240VAC |
| Frequency |
60 Hz (Default) |
| Max AC Current |
54A @ 240V |
| Max AC Input Power |
13,000 W |
| Max AC Bypass |
90A |
| Operating Voltage Range |
180 – 270 VAC |
| Output Voltage |
120/240VAC |
| Max Output Current |
66.7A |
| Output Frequency |
60 Hz (Default) |
| Nominal Output Power (without PV) |
12,000 W @ 240V |
| Nominal Output Power (with PV) |
16,000 W @ 240V |
| Power Factor |
0.99 (Full Load) |
| Reactive Power Adjustment Range |
-0.8 – 0.8 Leading Adjustable |
| Total Harmonic Distortion (THD) |
<5% (Full Load) |
| Transfer Time |
20 ms (Default) |
| Rated Output Current |
50A @ 240V |
| Rated Output Power |
12,000 W @ 240V |
| Peak Power |
20,000 W (0.5 sec) / 15,000 W (1 sec) / 12,500 W (6 min) / 11,000 W (12 min) |
| Operating Frequency |
60 Hz (Default) |
| Total Harmonic Distortion (Voltage) |
<5% |
| Number of MPPTs |
2 |
| Inputs per MPPT |
2 (MPPT 1) |
| Max Usable Input Current |
26A (MPPT 1) |
| Max Short Circuit Input Current |
31A (MPPT 1) |
| DC Input Voltage Range |
100 – 600 VDC |
| Unit Start-Up Voltage |
200 VDC |
| MPPT Operating Voltage Range |
120 – 440 VDC |
| Nominal MPPT Voltage |
360 VDC |
| Max Utilized PV Array Power |
18,000 W |
| Max Recommended PV Input |
18,000 W |
| Max Efficiency |
97.5% (PV→Grid) / 94.5% (PV→Battery) / 94% (Battery→Grid) |
| Idle Consumption |
<65W |
| Nominal Battery Voltage |
48 VDC |
| Battery Voltage Range |
40 – 60 VDC |
| Max Charge / Discharge Power |
10,000 W |
| Recommended Battery Capacity per Inverter |
>300 Ah |
| Operating / Storage Temperature Range |
-13ºF – 140ºF (-25ºC – 60ºC) |
| Operating Altitude |
<6,561 ft (2000 m) |
| Relative Humidity |
0 – 100% |
| Typical Noise Emission |
<50 dB @ 3 ft |
| Design Topology |
High-Frequency / Transformerless |
| Protection Rating |
IP65 / NEMA 4X |
| Communications |
RS485 / CANBus / WiFi / 4G |
| Max Parallel Connections |
10 |
Dimensions
| Weight |
115 lbs (52 kg) |
| Depth |
11.2 in (287 mm) |
| Width |
22.8 in (567 mm) |
| Height |
30.5 in (775 mm) |
What our Experts Think
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High-Capacity 13kW Output: Powers large homes or small commercial sites with stable, reliable AC supply.
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Supports Up to 18kW Solar Input: Maximizes solar harvesting for self-sufficient energy systems.
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Hybrid Energy Flexibility: Efficiently balances battery storage, solar generation, and grid interaction.
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Optimized for LiFePO4 Batteries: Delivers long lifespan, safe operation, and consistent performance.
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Advanced Energy Management: Includes MPPT tracking, load prioritization, and real-time system monitoring.
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Durable & User-Friendly: Built for heavy-duty use, with easy installation and minimal maintenance.
Q&A
Q: What is the Big Battery EG4 FlexBOSS18 Hybrid Inverter used for?
A: It’s designed for high-capacity off-grid and hybrid solar systems, converting DC from batteries and PV panels to AC for residential or commercial use.
Q: What is the power capacity?
A: Provides 13kW continuous output and supports up to 18kW PV input for maximum solar utilization.
Q: Is it compatible with Big Battery systems?
A: Yes. Fully compatible with EG4 and other Big Battery LiFePO4 packs for flexible hybrid setups.
Q: Does it support solar input?
A: Yes, it allows direct PV charging up to 18kW, optimizing renewable energy use.
Q: What protections are included?
A: Features overload, short-circuit, over/under-voltage, and thermal protections for safe operation.
Q: Is installation difficult?
A: Suitable for professional or experienced DIY installation, with clear DC and AC wiring connections.
Q: Why choose the FlexBOSS18 Hybrid Inverter?
A: Popular for high-capacity performance, hybrid flexibility, and seamless integration with Big Battery systems, providing reliable energy independence.
Maintenance Tips
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Inspect connections regularly: Check AC/DC terminals and wiring for tightness, corrosion, or wear.
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Keep cooling system clean: Ensure fans and vents are free from dust and debris to prevent overheating.
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Monitor system status: Use the display or monitoring software for error codes, voltage fluctuations, and temperature alerts.
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Firmware updates: Apply manufacturer-recommended updates to maintain efficiency and safety.
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Check grounding: Confirm proper grounding to prevent electrical hazards and ensure stable performance.
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Avoid overloading: Do not exceed the 13kW continuous output rating; high loads can reduce lifespan.
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Environmental care: Install in a dry, ventilated area away from sunlight, moisture, or corrosive materials.
