Product Description

The EG4 18kPV is an all-in-one hybrid solar inverter for whole-home systems. Per EG4, it utilizes up to 18,000W of solar across three MPPTs, delivers 12,000W of continuous split-phase 120/240V output, and charges a 48V battery bank at up to 250A — handling grid-tied operation, backup, and off-grid duty from a single NEMA 4X enclosure.

Questions about configuration or current availability on this model? Call us at (302) 496-3554 before you order — we will confirm the exact package and options for your project.

Who This Is For

Homeowners building whole-home solar-plus-storage — whether the goal is outage backup, solar self-consumption, or grid export where the utility allows it. The UL 1741 SB listing and California Rule 21 / Hawaii Rule 14H compliance published by EG4 matter if your utility requires a grid-support-capable inverter for interconnection. For off-grid-only projects that will never export, the XP series does the job without the interconnection paperwork.

Key Features

  • 12,000W continuous split-phase 120/240V output (50A), with peak capacity of 15,500W for 5 minutes per EG4's spec sheet
  • Up to 18,000W of utilized PV across three MPPTs (25A / 15A / 15A rated), 600 VDC max input
  • Grid-tied, grid-assist, and off-grid modes per EG4 — export is subject to your utility's interconnection approval
  • 48V battery charging/discharging up to 250A with closed-loop communications for compatible batteries
  • UL 1741 SA/SB with PCS CRD and UL 1699B arc-fault protection per EG4's published certifications
  • NEMA 4X enclosure rated for outdoor installation, -13 to 140 °F operating range
  • Parallel up to 10 units per EG4; built-in Wi-Fi with EG4 monitoring app

Why EG4

EG4 Electronics is a US-based manufacturer that publishes complete spec sheets, manuals, and wiring diagrams and maintains US-based technical support. The 18kPV is part of an integrated ecosystem: EG4 batteries communicate closed-loop with the inverter, and the EG4 GridBOSS MID lists the 18kPV among its supported hybrid inverters for whole-home backup switching.

Specifications

Specifications below are per EG4's published 18kPV spec sheet.

Continuous AC output 12,000W @ 240V (10,400W @ 208V), 50A max
Peak output 15,500W (5 min) with PV; 13,500W (10 min) without PV
Output voltage Split-phase 120/240VAC or 120/208VAC (L1/L2/N)
PV input 18,000W max utilized, 3 MPPTs (4 string inputs: 2/1/1)
MPPT voltage range 140–500 VDC (startup 100 VDC; max input 600 VDC)
PV current per MPPT 25A / 15A / 15A rated; 31A / 19A / 19A Isc
Battery voltage 40–60 VDC (48V-class); EG4 recommends ≥300Ah capacity
Max charge / discharge current 250A / 250A
AC input 120/240VAC, 50A / 12,000W max; 90A generator bypass
Transfer time 20 ms default (10 ms configurable)
Efficiency 96.9% CEC; 97.5% peak PV-to-grid
Idle consumption ~70W normal; ~18W standby
Parallel capability Up to 10 units
Certifications UL 1741 SA/SB with PCS CRD; UL 1699B; California Rule 21 Phase I–III; Hawaii Rule 14H
Enclosure / environment NEMA 4X; -13 to 140 °F
Dimensions / weight 34.3 x 20.5 x 11.2 in; 121 lb
Communications / monitoring RS485, Wi-Fi, CAN; EG4 app and web monitoring
Warranty 10-year standard per EG4 (registration required within first year)
SKU INV024

Grid-Tied, Backup, or Off-Grid

The 18kPV runs in three ways per EG4. Grid-tied: solar serves your loads and charges batteries, and surplus can be exported — but only if your utility approves the interconnection application; export capability and compensation vary by state and utility. Backup: when the grid drops, the inverter transfers to battery in 20 ms (10 ms configurable per EG4) and carries the loads it feeds. Off-grid: it will run with no utility connection at all, using the 90A generator bypass for extended cloudy stretches. Your installer sets the operating mode and any utility-required grid-support settings at commissioning.

Battery Compatibility

The 18kPV manages a 48V-class bank (40–60 VDC) with closed-loop communications to EG4 batteries. The EG4 WallMount 314Ah indoor battery (16 kWh, UL9540A-tested, self-heating) is a natural pairing, and EG4 recommends at least 300Ah of battery capacity behind this inverter — in practice, two or more 16 kWh WallMount units.

Installation

Installation is licensed-electrician work: the 18kPV interconnects with your main panel and, in grid-tied modes, with the utility, which requires an interconnection application before the system may export. Residential energy storage is subject to local permitting and inspection. The NEMA 4X enclosure allows outdoor mounting; plan for its 121 lb weight and clearances per EG4's manual. For whole-home backup switching at the service entrance, pair it with the EG4 GridBOSS 200A MID, which lists the 18kPV among its supported inverters.

Warranty & Support

Per EG4, the 18kPV carries a 10-year standard warranty; EG4 requires registration within the first year of purchase or proof of purchase from an authorized distributor. OffGrid Horizon is a family-owned authorized EG4 dealer — call (302) 496-3554 with sizing, configuration, or warranty questions and you will talk to a person, not a queue.

Shipping

Ships within the contiguous United States. At 121 lb, the 18kPV ships LTL freight on a pallet. Inspect packaging before signing the delivery receipt, note any damage with the driver, and call us immediately if something is wrong.

Frequently Asked Questions

Can it sell power back to the grid?

It is built for grid-interactive operation with UL 1741 SB per EG4 — but actual export depends on your utility approving your interconnection application, and compensation rules vary by state and utility. Confirm with your utility before counting on export revenue.

Does it work during a power outage?

Yes — with batteries attached it transfers to backup in 20 ms by default (10 ms configurable) per EG4 and carries the loads it feeds.

Can it run fully off-grid?

Yes. Off-grid is a supported mode per EG4, and a 90A generator bypass covers extended low-sun periods.

How many strings of panels can I connect?

Per EG4's spec sheet: four string inputs across three MPPTs (2/1/1), 600 VDC max, with MPPT current limits of 25A / 15A / 15A.

Is a battery required?

A 48V-class battery bank is central to how the 18kPV operates, and EG4 recommends at least 300Ah of capacity. Talk to us about the right bank for your loads.

Can I parallel multiple units?

Per EG4, up to 10 units can be paralleled.

18kPV or FlexBOSS21?

Both are EG4 hybrids. The 18kPV is the established all-in-one with 12 kW output and 3 MPPTs; the FlexBOSS21 offers 16 kW output with PV and pairs with GridBOSS via EG4's newer platform. Call us and we will walk through which fits your service and loads.

Not sure about configuration on this model? Call OffGrid Horizon at (302) 496-3554 — family-owned, authorized EG4 dealer — or browse the full EG4 collection.

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