Product Description

This kit pairs BigBattery's stackable ETHOS 48V LiFePO4 battery platform with the EG4 12000XP V2 off-grid inverter. Per EG4, the 12000XP delivers 12 kW of continuous split-phase 120/240V AC output, accepts up to 24 kW of PV input through two 35A MPPTs, and is built for installations that do not require grid sellback. This listing starts at 15.36 kWh of ETHOS storage (three 5.12 kWh modules) and is configurable to 30.72 kWh, with closed-loop communication between battery and inverter per BigBattery.

Who This System Is For

Off-grid homes and homesteads with real simultaneous loads — well pump, mini-splits, shop tools, and kitchen appliances at once — and grid-connected homes that want robust backup without utility export paperwork. Per EG4, the 12000XP can start a 5-ton air conditioner without a soft start, which makes it a practical choice where heavy motor loads are part of daily life.

Key Features

  • 12 kW continuous split-phase 120/240V output, per EG4 — heavy simultaneous loads without load-shedding gymnastics
  • Up to 24 kW of PV input through two 35A MPPTs, per EG4
  • Starts a 5-ton A/C without a soft start, per EG4
  • 100A grid input or 90A generator input for charging and bypass, with 2-wire generator auto-start, per EG4
  • Certified battery platform: ETHOS carries UL9540, UL9540A, UL1973, and UN38.3, per BigBattery; the inverter line is UL1741 listed per BigBattery's kit page
  • Closed-loop communication between ETHOS and the inverter, per BigBattery
  • Expandable: stack additional ETHOS modules (up to 16 parallel connections per control box, per BigBattery) or parallel up to 16 inverters, per EG4

Why BigBattery

BigBattery is a US-based energy storage company that has been building lithium battery systems since 2011 and, per BigBattery, is trusted by more than 50,000 Americans. BigBattery states its products are designed and engineered in Texas, includes free lifetime tech support with every product, and backs its batteries with a 12-Year Limited Warranty — described by BigBattery as "the longest warranty in the battery industry." OffGrid Horizon is a family-owned authorized BigBattery partner. See the full BigBattery collection.

What's In the Kit

  • 1 × EG4 12000XP V2 off-grid inverter
  • 3 × BigBattery ETHOS 48V 5.12 kWh LiFePO4 modules — 15.36 kWh base configuration for this listing, expandable to 30.72 kWh

Call (302) 496-3554 to confirm the configuration and accessories that ship with this SKU. BigBattery lists ETHOS inverter connectors and battery-to-battery connectors as separate accessories, so confirm cabling with your order. Solar panels, racking, and array wiring are sold separately.

Specifications

Battery BigBattery ETHOS, stackable LiFePO4 — see the ETHOS battery system
Module capacity 5.12 kWh / 100Ah per module, 51.2V nominal
Capacity (this listing) 15.36 kWh base (3 modules); configurable to 30.72 kWh
Max continuous discharge 250A (12,800W) for 3+ module stacks, per BigBattery
Dimensions / weight (3-module tower) 26.5" W × 6.7" D × 59.8" H; 387 lb, per BigBattery
Battery communications CAN bus / RS485; closed-loop with EG4, per BigBattery
Battery certifications UL9540, UL9540A, UL1973, UN38.3, per BigBattery
Cycle life 3,500–5,000 cycles (80% DoD, 0.5C), per BigBattery's spec sheet
Battery warranty BigBattery 12-Year Limited Warranty
Inverter EG4 12000XP V2 off-grid (per EG4)
AC output 12 kW continuous, split-phase 120/240V
PV input Up to 24 kW; two 35A MPPTs
Grid / generator input 100A from grid or 90A from generator; 100A bypass; 2-wire gen start
Grid export Not designed for grid sellback, per EG4
Parallel capability Up to 16 units, per EG4
Inverter warranty 5-year, per BigBattery's kit materials (registration per EG4 terms)

Grid-Tied, Off-Grid, or Backup?

The 12000XP is an off-grid inverter: per EG4, it is designed for installations not requiring grid sellback, so it does not export power to the utility. It can still use the grid — up to 100A of input for battery charging and pass-through bypass — which makes it a strong backup platform for grid-connected homes that do not want export interconnection. Whole-home backup is possible with adequate design, but coverage is load-dependent; 12 kW of continuous output handles most households' simultaneous loads.

Installation

All AC and DC wiring — panel interconnection, grounding, bonding, and overcurrent protection — must be performed by a licensed electrician in accordance with the National Electrical Code (NEC) and local amendments. Even off-grid and non-export systems typically require a permit and inspection in most jurisdictions. If the system connects to a grid-served panel for charging or bypass, your electrician should verify the arrangement against current NEC requirements for energy storage systems; no utility export interconnection is needed since the 12000XP does not sell power back.

Warranty & Support

Battery — BigBattery 12-Year Limited Warranty. Per BigBattery: "If any covered component within your battery fails due to a defect in materials or workmanship within the 12-year warranty period, we will repair or replace the battery at our cost." Included accessories carry a 1-year warranty per BigBattery, and BigBattery provides free lifetime tech support for all its products.

Inverter — 5-year warranty, per BigBattery's published kit materials; per EG4, inverter warranties must be registered within the first year of purchase (or proof of purchase from an EG4 authorized distributor provided) to remain valid.

Returns and warranty claims require an RMA. Contact us before shipping anything back — all returns must be authorized with a Return Merchandise Authorization first. OffGrid Horizon is a family-owned authorized BigBattery partner: call (302) 496-3554 and we will help open the claim and coordinate service.

Shipping

This kit ships as palletized LTL freight within the continental United States; curbside liftgate delivery is standard for residential addresses. The three-module ETHOS tower weighs 387 lb per BigBattery, plus the inverter — plan for help on delivery day. Before signing the delivery receipt, count the pieces and inspect the packaging; note any damage or shortage on the receipt with the driver and contact us immediately so we can open a freight claim. Per BigBattery, standard domestic orders are projected to take 7–12 days to deliver.

Frequently Asked Questions

Can the 12000XP sell power back to the grid?

No — per EG4, the XP line is designed for installations not requiring grid sellback. The grid can be used as a charging source and bypass (up to 100A input), but the inverter does not export.

What exactly ships at the listed price?

This listing starts at the 15.36 kWh configuration: one 12000XP V2 and three ETHOS modules. Call (302) 496-3554 to confirm accessories and to configure 20.48 or 30.72 kWh instead.

Can it run my air conditioner?

Per EG4, the 12000XP can start a 5-ton A/C without a soft start. Total coverage still depends on what else is running at the same time.

Does it support a generator?

Yes — per EG4, up to 90A of generator input with 2-wire auto start/stop, plus a programmable Smart Port for AC coupling or smart-load control.

How big a solar array can I connect?

Per EG4, up to 24 kW of PV input through two 35A MPPTs. Panels, racking, and wiring are sized to your site and sold separately.

Can the system grow later?

Yes, in two directions: stack more ETHOS modules (up to 16 parallel connections per control box, per BigBattery) or parallel up to 16 inverters, per EG4.

Will the battery charge in freezing weather?

Per BigBattery, the ETHOS charge range is 32°F to 113°F; the BMS restricts charging below freezing, so install the tower in an insulated or conditioned space in cold climates.

Sizing an off-grid system is mostly about your load list — call OffGrid Horizon at (302) 496-3554 and we'll walk through it with you. Family-owned, authorized BigBattery partner.

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