Product Description

The BigBattery NEXUS is a 48V-class LiFePO4 battery for off-grid homes, cabins, and backup power systems. BigBattery's published specifications list 280Ah of capacity and 14.3 kWh of usable energy from a single floor-standing cabinet, with a 6,000+ cycle life rating and a built-in battery management system (BMS). It is the same battery at the core of our NEXUS off-grid kits with APEX and EG4 inverters.

Who This Is For

The NEXUS suits off-grid households and cabin owners who want large capacity in a few cabinets rather than a wall of small rack modules, homeowners adding storage to an existing 48V inverter, and anyone planning a bank that will grow over time — per BigBattery, up to 15 units parallel together. If you want battery and inverter as a matched package, we also carry NEXUS kits built around the APEX 6.5K and EG4 6000XP inverters.

Key Features

  • 280Ah capacity, 14.3 kWh usable energy per unit (51.2V nominal, 16S1P), per BigBattery
  • 140A maximum continuous discharge — 7.6 kW maximum continuous power — with a 270A (1-second) peak, per BigBattery
  • 6,000+ cycle life, per BigBattery
  • Self-heating function and integrated aerosol fire suppression, per BigBattery
  • RS485 / RJ45 / CAN communications — compatible with all BigBattery APEX inverters and all EG4 inverters, per BigBattery
  • Parallels up to 15 units for up to 214.5 kWh, per BigBattery
  • IP54 protection rating, per BigBattery

Why BigBattery

BigBattery is a US company building LiFePO4 energy storage for off-grid, home backup, and industrial use. NEXUS batteries ship from Texas and are backed by BigBattery's 12-Year Limited Warranty and lifetime USA-based technical support, per BigBattery. Browse our full BigBattery collection.

Specifications

System voltage 48V class (51.2V nominal)
Capacity 280Ah
Usable energy 14.3 kWh, per BigBattery
Chemistry LiFePO4 (lithium iron phosphate), 16S1P
Max continuous discharge 140A (7.6 kW max continuous power)
Peak discharge 270A (1 second)
Max charge current 140A
Cycle life 6,000+ cycles, per BigBattery
Communications RS485 / RJ45 / CAN
Parallel capability Up to 15 units (up to 214.5 kWh), per BigBattery
Protection BMS with voltage, current, and temperature protection; IP54 rating
Thermal Self-heating function; integrated aerosol fire suppression
Charge temperature 32°F to 113°F
Discharge temperature −4°F to 113°F
Dimensions (W × H × D) 19.7 × 27.5 × 15.7 in
Weight Approx. 315 lb
Warranty 12-Year Limited Warranty, per BigBattery
SKU F-NXUS-48150-G1

All figures are BigBattery's published specifications. BigBattery markets the NEXUS in its 15 kWh class; the spec sheet lists usable energy of 14.3 kWh, and we quote the spec-sheet figure so you can size on the number you'll actually use.

Building a 48V Bank

Two numbers drive bank design: continuous power and stored energy. On power, each NEXUS supports 140A of continuous discharge — about 7.6 kW — per BigBattery. A 6,000–6,500W inverter can run at its full rating on a single NEXUS; a 10,000–12,000W inverter needs at least two units in parallel before the battery side matches the inverter's continuous rating (two units, adding BigBattery's per-unit figures, support up to 280A, or about 15.2 kW).

On energy, work from daily consumption. Example assumptions — yours will differ: refrigerator 1.5 kWh/day, chest freezer 1.0, LED lighting 0.4, well pump 1.0, electronics and internet 1.0. That is about 4.9 kWh/day for an efficient cabin, so one NEXUS at 14.3 kWh usable (per BigBattery) covers roughly two such days without sun. A full-time household running laundry, kitchen appliances, and air conditioning can use 20–30 kWh/day, which is where two or three units earn their keep. Up to 15 units parallel per BigBattery, so you can start with one and grow.

Installation

Plan placement first: each cabinet weighs approximately 315 lb (per BigBattery), so the route into the building, floor loading, and a two-person or equipment-assisted move all matter. Install in a dry, conditioned space — the published charge range starts at 32°F, and while the pack includes a self-heating function, an insulated or heated utility area is the dependable answer for winter charging. All AC and DC wiring, overcurrent protection, grounding, and interconnection should be performed by a licensed electrician to the National Electrical Code (NEC) and local codes; most jurisdictions require a permit and inspection for energy storage.

Warranty & Support

The NEXUS is 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.” Per BigBattery, included accessories are covered for 1 year, and no warranty registration is needed — coverage is recorded automatically by serial number. BigBattery also publishes a 30-Day Money Back Guarantee; per BigBattery, non-defective returns are refunded at the purchase price minus a 20% restocking fee, and reimbursements do not include shipping costs.

All returns require a Return Merchandise Authorization (RMA) before anything ships back. OffGrid Horizon is a family-owned authorized BigBattery partner — call us at (302) 496-3554 and we will open the RMA or warranty claim with BigBattery and see it through with you. BigBattery backs its batteries with lifetime USA-based technical support.

Shipping

The NEXUS ships as palletized freight within the United States. When the carrier arrives, inspect the pallet and cabinet before signing: note any dents, punctures, or a tipped pallet on the delivery receipt, and contact us promptly if anything looks wrong — that notation keeps a freight claim straightforward.

Frequently Asked Questions

Is this battery really 15 kWh?

BigBattery markets the NEXUS in its 15 kWh class; the published spec sheet lists 280Ah and 14.3 kWh of usable energy. We quote the spec-sheet figure.

Which inverters does it work with?

Per BigBattery, the NEXUS is compatible with all BigBattery APEX inverters and all EG4 inverters, communicating over RS485 / RJ45 / CAN. Pairing with another 48V inverter brand? Call us and we'll check before you order.

How many units can I parallel?

Up to 15 in parallel, for up to 214.5 kWh, per BigBattery.

How does it handle cold weather?

BigBattery lists discharge from −4°F to 113°F and charge from 32°F to 113°F, with a self-heating function built in. For year-round charging, install it in a space that stays above freezing.

Do I need to register the warranty?

No. Per BigBattery, warranties are recorded automatically by serial number — keep your order confirmation as proof of purchase.

Can it be installed outdoors?

The cabinet carries an IP54 protection rating per BigBattery, but temperature is the practical constraint — charging is specified from 32°F up. A garage, utility room, or insulated enclosure is the safer siting in most of the US.

Sizing a bank or matching an inverter? Call OffGrid Horizon at (302) 496-3554 — we're a family-owned authorized BigBattery partner and glad to help you get it right.

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