Dual EG4 FlexBOSS 18 + GridBOSS Hybrid Whole-Home Solar Kit | 20kW 120/240V | 20kW Solar | 48kWh Battery

Price range: $28,088.84 through $30,973.34

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A solar kit built around two EG4 FlexBOSS 18 hybrid inverter with GridBOSSs.

  • 20 kW continuous 120/240V split-phase output
  • Solar: 50 × 400W panels (20 kW DC)
  • Storage: 48 kWh (3 × 16 kWh Wall/Floor-Mount) EG4 WallMount LiFePO4
  • Optional Tigo rapid shutdown or Tigo optimizers
  • Exports solar where your utility allows

Racking sold separately.

SKU: WEB-PARENT-DUAL-EG4-FLEXBOSS-18-GRIDBOSS-SOLAR-KIT Categories: , , Brand:

Whole-Home Hybrid · Backup · Off-Grid

Dual EG4 FlexBOSS 18 + GridBOSS Hybrid Whole-Home Solar Kit | 20kW 120/240V | 20kW Solar | 48kWh Battery

This kit is built around two EG4 FlexBOSS 18 hybrid inverter with GridBOSSs, delivering 20 kW of continuous 120/240V split-phase output, paired with 50 × 400W panels (20 kW DC) and 48 kWh (3 × 16 kWh Wall/Floor-Mount) of storage.

At a Glance
  • 20 kW continuous AC output, 120/240V split-phase
  • Surge capacity up to 40 kW for motor starting
  • Solar array: 50 × 400W panels (20 kW DC)
  • Battery options: 48 kWh (3 × 16 kWh Wall/Floor-Mount) (EG4 WallMount LiFePO4)
  • Exports solar where your utility allows
  • Optional Tigo rapid shutdown or Tigo optimizers + rapid shutdown

Choose Your Configuration

Battery Storage 48 kWh (3 × 16 kWh Wall/Floor-Mount)
Rack-Mount batteries install in a battery rack or cabinet; Wall/Floor-Mount batteries mount on a wall or stand on the floor.
Rapid Shutdown None: includes PV disconnects
Tigo Rapid Shutdown: TS4-A-F on every panel
Tigo Optimizers + Rapid Shutdown: TS4-A-O on every panel plus Tigo CCA monitoring kit

Options are offered in specific combinations; available combinations are shown in the selector above.

Rapid Shutdown or Optimizers?

None (PV disconnects) Best for ground-mounted arrays or other installations where module-level rapid shutdown isn’t required. Includes PV disconnects.
Tigo Rapid Shutdown Required for most roof-mounted arrays on buildings (NEC 690.12). A TS4-A-F on each panel drops the array to a safe voltage within seconds when the system is shut off, protecting firefighters and service crews.
Tigo Optimizers + Rapid Shutdown Everything rapid shutdown does, plus panel-level optimization and monitoring. Each TS4-A-O lets panels work independently, so shade, soiling or panels on different roof planes don’t drag down the whole string, and the Tigo CCA shows each panel’s output.

Rapid shutdown requirements depend on the code adopted by your jurisdiction; confirm with your AHJ.

Estimated Annual Solar Production

Phoenix, Arizona ~34,000 (50P) kWh/year
Chicago, Illinois ~25,200 (50P) kWh/year

Planning estimates for an unshaded, south-facing array at about 30° tilt with typical losses. Actual production varies with location, orientation, tilt, shading, weather and equipment. Use a site-specific model before purchase.

System Overview

The kit pairs the inverter with an array sized to refill the battery on an average day (3.5 peak sun hours) and a battery bank that can deliver the inverter’s full output.

Ideal Applications

  • Whole-home backup for larger homes with additional major loads
  • Larger off-grid homes
  • Agricultural power: multiple pumps and motors

What’s Included

  • Two EG4 FlexBOSS 18 hybrid inverter with GridBOSS units
  • ALEX-400 400W solar panels (count per configuration)
  • EG4 WallMount LiFePO4 (battery configurations), with mounting and battery cabling
  • MC4 connector pairs and 10 AWG PV wire (black and red)
  • PV disconnects (one per two strings) on configurations without rapid shutdown
  • Tigo options: TS4-A-F rapid shutdown devices, or TS4-A-O optimizers with a Tigo CCA kit (plus Tigo TAPs on larger arrays)
Installation note: Racking is sold separately. Site-specific wire and conduit, breakers, service and interconnection equipment, and permitting materials may be required. Utility and AHJ requirements vary; final design must follow manufacturer instructions and applicable code.
Weight N/A
Dimensions 72 × 48 × 54 in
Brand

Inverter Platform

EG4 FlexBOSS 18 + GridBOSS

Inverter Quantity

Dual

Continuous Output

20 kW

Inverter Size (KW)

20KW–30kW

Output (V)

120V/240V

Grid Connection

Grid-Interactive Hybrid (Can Export)

Generator Compatible

Yes

Inverter Type

All-in-one Inverter

Solar Capacity (DC)

20KW–30kW

Battery Capacity (KWH)

40KWH-50KWH

Solar Array

50 Panels (20 kW)

Battery Storage

48 kWh

Rapid Shutdown

None, Tigo Optimizers + Rapid Shutdown, Tigo Rapid Shutdown

What Can It Power?

Built around the EG4 FlexBOSS 18 with GridBOSS, a hybrid inverter paired with GridBOSS for whole-home backup, this kit delivers 20 kW of continuous 120/240V split-phase output.

20 kW
Continuous output, 120/240V split-phase
40 kW
Surge for motor starting
48 kWh
Battery storage options
20 kW
Solar array (400W panels)
What you can run
Everyday essentials

0.5–1.5 kW

Refrigerator and freezer, LED lights, ceiling fans, phone and laptop charging, modem, router and TV. These small and cycling loads are the starting point for long outage coverage.

Kitchen, laundry & larger loads

1.5–5 kW each

Microwave, coffee maker, washer or dishwasher as needed. An electric water heater, dryer, oven or range can use a large share of the output, so stagger them instead of running them together.

Cooling, pumps & shop tools

Check starting current

A compatible mini-split, central HVAC, well pump or shop tool may run when its running demand and starting current fit within 20 kW continuous and 40 kW surge. Check the actual equipment; tonnage or horsepower alone doesn’t confirm it. A soft starter can help some compressors.

Illustrative operating mixes
Refrigerator/freezer, LED lights, internet, TV and fans0.5–1.5 kW
Essentials + microwave or coffee maker2–3.5 kW while it runs
Essentials + a smaller inverter mini-split1.5–3 kW
Essentials + a 4.5 kW electric water heater5–6 kW while heating
Essentials + 3-ton central A/C running4–6 kW plus a large starting surge
Whole home: HVAC, cooking and laundry at once8–15 kW
Plan around the limits
Add up the loads that run at the same time and allow for motor starts. For a 20 kW split-phase system, keep loads balanced across the two 120V legs: a heavily loaded leg can reach its limit before the total does. A larger battery adds runtime but doesn’t raise the inverter’s output. Examples are planning illustrations, not guaranteed appliance packages.

How Long Will It Run?

Battery size sets how much energy you have. These battery-only estimates use 80% of nominal storage delivered to loads (38.4 kWh from 48 kWh).

0.5 kW · Lean essentials / light overnight use
48 kWh

76.8 hrs

1 kW · Essentials with more appliance use
48 kWh

38.4 hrs

2 kW · Moderate household use
48 kWh

19.2 hrs

4 kW · Higher sustained use
48 kWh

9.6 hrs

10 kW · Heavy sustained use
48 kWh

3.8 hrs

20 kW · Full rated output
48 kWh

1.9 hrs

Runtime = usable battery energy ÷ average load, starting full, with no solar, grid or generator. Average load includes cycling: a 1 kW appliance running half the time averages about 0.5 kW. Actual results depend on settings, battery condition, temperature and system consumption.

At 12 kWh per day
3.2 days on 48 kWh
At 24 kWh per day
1.6 days on 48 kWh

Cooling, heating and electric water heating can change daily totals substantially.

What Does Solar Add?

Solar powers daytime loads and recharges the battery with what’s left.

50 panels · 20 kW DC
≈ 56 kWh / day
≈ 20,400 kWh / year

Illustration: 3.5 peak sun hours × array rating × 80% system yield, rounded. Not a location-specific forecast. Household use draws from this energy too, so not all of it refills the battery. Shading, winter and cloudy days can sharply reduce production.

When Solar Isn’t Enough

Utility available
Solar powers the home first and charges the battery; GridBOSS manages the grid connection and can export surplus where your utility allows.
Grid outage: solar + battery
The system supplies only the circuits connected to its backup output, from solar and stored energy. Plan for the 20 kW output limit, battery discharge limits and motor starts, and shed large loads to extend runtime. A properly configured compatible generator can carry extended low-sun periods (not included).

Why This System?

The Dual EG4 FlexBOSS 18 + GridBOSS Hybrid Whole-Home Solar Kit is built around the EG4 FlexBOSS 18 with GridBOSS, a hybrid inverter paired with GridBOSS for whole-home backup. Match the configuration to your daily energy use, the loads that run together and your installation.

20 kW for a useful mix of loads

120/240V split-phase output runs common household circuits and compatible 240V equipment. Manage what runs together and check motor starts for HVAC, pumps or shop tools.

GridBOSS whole-home control

GridBOSS manages the grid, generator and home loads for whole-home backup.

Parallel-capable

Add FlexBOSS units to scale output for larger homes.

Generator integration

Bring in a generator for long outages (generator sold separately).

Matched as a system

The battery bank can deliver the inverter’s full output, the array is sized to recharge the battery, and strings are laid out within the inverter’s limits.

Choose Your Size

50 panels · 20 kW DC solar · 38.4 kWh usable
48 kWh

A balanced step up in solar and runtime.

Only the combinations shown in the product selector are offered. Every option uses the same EG4 FlexBOSS 18 with GridBOSS configuration.

Choose the Right Panel Electronics

None
Best for

Ground-mounted arrays and other installs where module-level rapid shutdown isn’t required. Includes PV disconnects.

Tigo Rapid Shutdown
Best for

Most roof-mounted arrays on buildings, where code requires module-level shutdown (NEC 690.12).

Tigo Optimizers + Rapid Shutdown
Best for

Rapid shutdown plus panel-level optimization and monitoring. Helps with mismatch from partial shade or different roof planes; it can’t recover sunlight lost to shade.

Plan the system around your site
This platform can export solar to the utility where your utility allows and your interconnection agreement permits. Racking, site-specific electrical materials and installation are additional.

Other Sizes on This Platform

EG4 FlexBOSS 18 + GridBOSS Hybrid Whole-Home Solar Kit | 10kW 120/240V | 10.4kW Solar | 32kWh Battery
Triple EG4 FlexBOSS 18 + GridBOSS Hybrid Whole-Home Solar Kit | 30kW 120/240V | 28kW Solar | 64kWh Battery

Reference: EG4 FlexBOSS 18 with GridBOSS manufacturer information.

Frequently Asked Questions

Does this kit include batteries?
Yes: 48 kWh (3 × 16 kWh Wall/Floor-Mount) of EG4 WallMount LiFePO4, per the option you choose.
Will it power my home during an outage?
Yes, for the circuits connected to its backup output (or the whole home with a whole-home interface).
What is the solar array size?
50 × 400W panels (20 kW DC).
What output does it provide?
20 kW continuous at 120/240V split-phase.
Can I sell excess solar to the utility?
Yes, where your utility allows and your interconnection agreement permits.
Can I connect a generator?
Yes. Use an inverter-style generator (3–5% THD) with 2-wire auto-start for automatic control. Generator not included.
What is the difference between the rapid shutdown options?
None includes PV disconnects. Tigo Rapid Shutdown adds a TS4-A-F to every panel. Tigo Optimizers + Rapid Shutdown adds a TS4-A-O to every panel plus a Tigo CCA kit for panel-level monitoring. Your AHJ may require rapid shutdown for roof-mounted arrays.
Is racking included?
No. Roof or ground-mount racking is site-specific and sold separately.
Are all breakers, wire and conduit included?
Not necessarily. Site-specific wire, conduit, breakers, service upgrades and interconnection hardware may be required.
Will this eliminate my electric bill?
No specific savings are guaranteed. Rate structure, fixed charges, export compensation, usage and production all affect the final bill.
Do I need permits or utility approval?
Most installations need permits and inspections, and grid-connected systems need utility interconnection approval. Requirements vary by location.
Can this be installed DIY?
That depends on your jurisdiction and utility. Electrical work must follow manufacturer instructions, adopted code and any licensing requirements.
How do I know which configuration is right for me?
Use our kit selector, or contact SanTan Solar to match the system to your loads, usage and runtime needs.
Still have questions?

Contact SanTan Solar for help matching the system to your project.

EG4-FlexBOSS18-Hybrid-Inverter-User-ManualDownload
EG4 FlexBOSS 18 - Manual / installation guide
EG4-FlexBOSS18-Hybrid-Inverter-Spec-SheetDownload
EG4 FlexBOSS 18 - Datasheet
EG4-FlexBOSS18-System-Wiring-DiagramsDownload
EG4 FlexBOSS 18 - Wiring diagrams
EG4-FlexBOSS18-UL-1741-Certificate-of-ComplianceDownload
EG4 FlexBOSS 18 - Certificate
gridboss_user_03_manualDownload
EG4 GridBOSS - Manual / installation guide
gridboss_spec_sheetDownload
EG4 GridBOSS - Datasheet
wiring_diagram_gridbossDownload
EG4 GridBOSS - Wiring diagrams
UL_1741_cert_gridbossDownload
EG4 GridBOSS - Certificate
UL_67_809A_916_cert_gridbossDownload
EG4 GridBOSS - Certificate
Manual_314AHDownload
EG4 314Ah indoor battery - Manual / installation guide
EG4-WallMount-314Ah-Indoor-Battery-Spec-SheetDownload
EG4 314Ah indoor battery - Datasheet
EG4-WallMount-314Ah-Indoor-Battery-Quick-Start-GuideDownload
EG4 314Ah indoor battery - Quick start guide
EG4-WallMount-314Ah-Indoor-Battery-1973-Certificate-of-Compliance.pdf (SECURED)Download
EG4 314Ah indoor battery - Certificate
EG4-WallMount-314Ah-Indoor-Battery-UL-9540A-Test-Verification-of-Conformity.pdf (SECURED)Download
EG4 314Ah indoor battery - UL 9540A Test Verification
ALEX-390~410-B-54-SDownload
Alexus ALEX-400-B-54-S - Datasheet
688276b9f911953631c3be72_002-00222-00 1.1 Datasheet TS4-A-F (725W) 20250710 - ENDownload
Tigo TS4-A-F - Datasheet (Rapid shutdown option)
Tigo TS4-A-F Installation ManaualDownload
Tigo TS4-A-F - Manual / installation guide (Rapid shutdown option)
data_TS4-A-ODownload
Tigo TS4-A-O and CCA/TAP - Datasheet (Optimizer option)
install_cca_and_tapDownload
Tigo TS4-A-O and CCA/TAP - Manual / installation guide (Optimizer option)
start_guide_cca_and_tapDownload
Tigo TS4-A-O and CCA/TAP - Quick start guide (Optimizer option)
install_TS4-A-ODownload
Tigo TS4-A-O - Manual / installation guide (Optimizer option)
start_TS4-A-ODownload
Tigo TS4-A-O - Manual / installation guide (Optimizer option)

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