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BigBattery

BigBattery NEXUS + EG4 12000XP V2 Off-Grid Kit | 15 kWh | 48V LiFePO4

SKU K0154

Regular price: $4,940.00

Regular price: $4,940.00

✅ Order by 12:00 PM EST and processing starts the same day (ships within 1–2 business days). Free, insured US shipping — delivery in 4–7 business days. Oversized items ship via LTL freight and we coordinate delivery with you by phone.

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OffGrid Horizon Family Owned and Operated

🏔️ OffGrid Horizon is family-owned & off-grid obsessed. Read our story →

Shipping: how fast & how it works

Free standard shipping on every US order — no shipping charges at checkout, no hidden fees, and every shipment is insured against loss or damage.

Processing: 1–2 business days. Order before 12:00 PM EST and processing begins the same day.
Delivery: 4–7 business days via USPS, UPS or FedEx. Tracking is emailed the moment your order ships.
Large items (solar kits, batteries, shelters): delivered by LTL freight carriers such as FedEx Freight, Old Dominion or XPO. The carrier calls ahead to schedule a delivery window — please inspect the pallet and note any damage on the delivery receipt before signing, and we’ll take care of the rest.

Questions about delivery to your location? Call (302) 496-3554 (Mon–Fri, 9am–4pm EST) — we’re happy to check before you order.

What is your Return Policy?

At OffGrid Horizon, we want every customer to shop with confidence. If something doesn’t go as planned, we’ve made returns and refunds simple and fair. Here’s how it works:

1. Return Window

You can request a return within 30 days of receiving your order. Unfortunately, we’re unable to accept returns after that time frame.

2. Who Pays for Return Shipping?

If your item arrives damaged, defective, or incorrect, we’ll cover the return shipping cost — and you’ll receive a full 100% refund or replacement, including any original shipping costs.
If you’re returning an item because you changed your mind, you’ll be responsible for return shipping, and a 25% restocking fee applies.

3. Damaged or Defective Items

Received something broken or not working properly? Contact us within 30 days. We’ll provide a prepaid return label and once the item is returned and inspected, we’ll issue either a full refund or a replacement.

4. Changed Your Mind?

If you no longer want the item, you can return it within 30 days — as long as it’s unused, unopened, in its original packaging, and in resellable condition.

5. Refund Processing

Once we receive and approve your return, we’ll send a confirmation email and issue a refund to your original payment method within 7 business days. Please allow additional time for banks or credit card companies to process and reflect the refund.

How to start a return: email sales@offgridhorizon.com or call (302) 496-3554 (Mon–Fri, 9am–4pm EST) with your order number — we’ll send return instructions and your RMA right away.

Product Description

The BigBattery NEXUS + EG4 12000XP V2 Off-Grid Kit combines a 15 kWh NEXUS 48V LiFePO4 battery with EG4's flagship 12000XP V2 all-in-one off-grid inverter — a whole-home-class power system for full-size off-grid residences, large workshops, and properties running heavy 240V loads. The 12000XP V2 delivers 12,000W of continuous split-phase output with integrated MPPT solar charge controllers and battery charging in one wall-mounted enclosure.

What's in this kit

1 × BigBattery NEXUS 48V LiFePO4 battery — 15 kWh usable energy storage in a floor-standing cabinet with an integrated battery management system (BMS)
1 × EG4 12000XP V2 all-in-one inverter — 12,000W continuous split-phase 120/240V output, integrated MPPT solar charge controllers, and built-in AC charging
Closed-loop communication between battery and inverter for accurate state-of-charge reporting and coordinated charging

Is this the right size for you?

It fits if: you're powering a full-size home or large property off-grid — central or multi-zone air conditioning, a well pump, electric range or dryer, and everyday household loads running at the same time. 12,000W continuous output is enough headroom that you rarely have to think about what's on.

Size down if: your loads are closer to cabin or tiny-home scale. The NEXUS + EG4 6000XP kit or NEXUS + APEX 6.5K kit deliver the same 15 kWh of storage with a smaller, lower-cost inverter.

Add storage if: you're running large loads through the night — a single 15 kWh NEXUS is the starting point, and additional NEXUS batteries parallel onto the same 48V bus as your usage grows.

Specifications

Battery	BigBattery NEXUS, 48V LiFePO4
Energy storage	15 kWh
Battery chemistry	Lithium iron phosphate (LiFePO4)
Inverter	EG4 12000XP V2 all-in-one
Continuous output	12,000W, split-phase 120/240V
Solar (PV) input	Integrated MPPT charge controllers
System voltage	48V nominal
Communication	Closed-loop battery-to-inverter
Expandable	Yes — additional NEXUS batteries can be added in parallel

Warranty & support

Battery: the NEXUS is covered by BigBattery's 12-year manufacturer warranty, backed by lifetime USA-based technical support. Inverter: the EG4 12000XP V2 carries a 5-year full parts-or-product replacement manufacturer warranty; EG4 requires warranty registration within the first year of purchase (or proof of purchase from an authorized distributor) to keep coverage valid.

Common questions

Do I need an electrician to install this?

The battery-to-inverter DC connection uses supplied cabling, but the AC side — wiring 12,000W of split-phase output into your main panel — should be performed by a licensed electrician to meet local code.

Are solar panels included?

No. This kit is the storage and inverter core of the system; solar panels are sold separately so you can size the array to your site and the inverter's MPPT input range.

How does LiFePO4 handle cold weather?

LiFePO4 batteries discharge reliably in freezing temperatures, but charging below freezing is restricted by the BMS to protect the cells. Installing the battery in an insulated or conditioned space keeps charging available year-round.

Can I add more storage later?

Yes. Additional NEXUS batteries parallel onto the same 48V bus, so the battery bank can grow with your household without replacing the inverter.