Product Description

This is the multi-battery configuration of the NEXUS + EG4 6000XP system: two or three BigBattery NEXUS 48V LiFePO4 batteries — 280Ah and 14.3 kWh usable each, per BigBattery — with the EG4 6000XP all-in-one off-grid inverter: 6,000W of continuous split-phase 120/240V output and dual MPPTs accepting up to 8,000W of PV, per EG4. It is built for multi-day autonomy rather than short outages — homesteads and off-grid households that live off the bank every day. Per BigBattery, the NEXUS is compatible with all EG4 inverters over RS485 / RJ45 / CAN communications.

Who This Is For

Cabins and homesteads with moderate loads — refrigeration, lighting, a water pump, electronics, and everyday 240V appliances — that cycle the bank daily and want to ride out nights and cloudy stretches without a generator. If you run central air or a well pump plus large appliances simultaneously, the EG4 12000XP V2 version doubles the inverter output on the same battery platform.

Key Features

  • Choose 2 × NEXUS (30 kWh class) or 3 × NEXUS (45 kWh class) — 28.6 or 42.9 kWh usable, adding BigBattery's 14.3 kWh per-unit figure
  • 6,000W continuous split-phase 120/240V output, per EG4; surge rated 12,000W (3.5 seconds), per BigBattery's kit listing
  • Up to 8,000W of PV input — 4,000W per MPPT across dual MPPTs, with high 480Vdc input, per EG4
  • UL 1741 Certified transformerless design, idle as low as 30W with PV, per EG4
  • Parallels up to 16 inverters (96 kW combined), per EG4; batteries parallel up to 15 units, per BigBattery
  • NEXUS batteries: 6,000+ cycle life, self-heating function, aerosol fire suppression, per BigBattery

Why BigBattery

BigBattery is a US company building LiFePO4 energy storage for off-grid and home backup use. NEXUS batteries ship from Texas, carry a 12-Year Limited Warranty, and are backed by lifetime USA-based technical support, per BigBattery — here matched with EG4's widely installed 6000XP. Browse our EG4 collection for the rest of the line.

What's In the Kit

Solar panels, racking, and array wiring are not included. BigBattery's kit listing does not itemize cables or accessories, so call us at (302) 496-3554 before ordering and we'll confirm exactly what ships with your configuration.

Specifications

Batteries 2 or 3 × BigBattery NEXUS, 48V class (51.2V nominal), LiFePO4, 280Ah each
Usable energy 14.3 kWh per battery, per BigBattery — 28.6 kWh (2 units) or 42.9 kWh (3 units) total
Battery max continuous discharge 140A (7.6 kW) per battery, per BigBattery
Battery cycle life 6,000+ cycles, per BigBattery
Battery communications RS485 / RJ45 / CAN; compatible with all EG4 inverters, per BigBattery
Battery dimensions / weight 19.7 × 27.5 × 15.7 in; approx. 315 lb — each
Inverter EG4 6000XP — 6,000W continuous, split-phase 120/240V, per EG4
Surge 12,000W (3.5 s), per BigBattery's kit listing
Solar input Up to 8,000W (4,000W per MPPT), dual MPPTs, high 480Vdc input, per EG4
Inverter parallel capability Up to 16 units (96 kW combined), per EG4
Inverter certifications UL 1741 Certified, per EG4
Battery warranty 12-Year Limited Warranty, per BigBattery
Inverter warranty 5-year full parts replacement or full product replacement warranty, per EG4 (registration or authorized-distributor proof of purchase required — see below)
Kit SKU K0153 (2 batteries) / K0157 (3 batteries)

Sizing Your Off-Grid Home

Example assumptions for a lived-in homestead — label and adjust for your own site: refrigerator 1.5 kWh/day, chest freezer 1.0, LED lighting 1.0, well pump 1.5, electronics and internet 1.5, laundry and kitchen 2.0. That is about 8.5 kWh/day before climate loads; a mini-split commonly adds 5–15 kWh/day in season, bringing many households to 14–20 kWh/day.

Two NEXUS (28.6 kWh usable, per BigBattery's per-unit figure) is roughly a day and a half to two days of autonomy at that rate; three (42.9 kWh) stretches toward three days. On power, keep simultaneous loads under the 6000XP's 6,000W rating — the battery side is never the constraint here, since even one NEXUS supports about 7.6 kW continuous per BigBattery. And 8,000W of PV (per EG4) refills a bank this size quickly in decent sun.

Installation

Each battery cabinet weighs approximately 315 lb, so plan floor space and the move for two or three of them, plus wall space for the inverter. The AC side — panel interconnection, overcurrent protection, grounding, bonding — belongs to a licensed electrician working to the National Electrical Code (NEC) and local codes; most jurisdictions require a permit and inspection for energy storage. Keep the batteries in a dry space above freezing; BigBattery's published charge range starts at 32°F.

Warranty & Support

Batteries: covered by BigBattery's 12-Year Limited Warranty — in BigBattery's words, “BigBattery, Inc. guarantees that its products will be free from defects in material and workmanship for a period of twelve (12) years.” No registration needed, per BigBattery. Inverter: the EG4 6000XP carries a 5-year full parts replacement or full product replacement warranty, per EG4, which states the warranty “must be registered within the first year of purchase or provide proof of purchase from an EG4 authorized distributor to remain valid.”

BigBattery publishes a 30-Day Money Back Guarantee; per BigBattery, non-defective returns are refunded at purchase price minus a 20% restocking fee, excluding shipping. All returns require a Return Merchandise Authorization (RMA) before anything ships back — call OffGrid Horizon at (302) 496-3554 and we'll open the RMA or warranty claim. We're a family-owned authorized BigBattery partner, and BigBattery backs its batteries with lifetime USA-based technical support.

Shipping

This kit ships as palletized freight within the United States — two or three battery cabinets plus the inverter. Inspect every pallet before signing: note any damage on the delivery receipt and contact us promptly — that notation keeps a freight claim simple.

Frequently Asked Questions

What exactly does the listed price include?

The Battery Configuration you select — two or three NEXUS batteries — plus one EG4 6000XP inverter. The price updates with your selection. Panels and racking are separate.

Two batteries or three?

Size to your daily consumption and the cloudy stretch you want to cover. Households near 14–18 kWh/day usually do well at 28.6 kWh usable; heavier use or longer weather points to three. The bank grows later too — up to 15 in parallel, per BigBattery.

Is this a grid-tie system?

No — the 6000XP is an off-grid inverter, and per BigBattery the pairing is sold for home backup and off-grid operation, not as a grid-interactive (sell-back) system.

Is 6,000W enough output for this much storage?

If your simultaneous loads stay under 6,000W — typical for cabins and efficient homesteads — yes; deep storage is about autonomy, not peak power. For heavier simultaneous loads, see the EG4 12000XP V2 version.

What about inverter warranty registration?

Per EG4, register within the first year or keep proof of purchase from an authorized distributor. Keep your order confirmation, and call us if you'd like a hand.

Do I need an electrician?

Yes — AC interconnection, grounding, and code compliance are work for a licensed electrician, and most jurisdictions require a permit and inspection.

Want a sanity check on your load list before you pick two or three batteries? Call OffGrid Horizon at (302) 496-3554 — family-owned, authorized BigBattery partner.

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