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BigBattery

BigBattery NEXUS + APEX 10K Off-Grid Kit | 15 kWh | 48V LiFePO4

SKU K0196

Regular price: $4,725.00

Regular price: $4,725.00

✅ 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 single-battery configuration of the NEXUS + APEX 10K system: one BigBattery NEXUS 48V LiFePO4 battery — 15 kWh of storage — matched with the APEX 10K, the higher-output all-in-one inverter in the APEX line. With 10,000W of continuous split-phase 120/240V output plus an integrated MPPT solar charge controller and battery charger, this kit suits properties whose challenge is peak power — larger motors, pumps, shop tools, several 240V appliances at once — while keeping storage at an entry-level footprint that can grow later.

What's in this kit

1 × BigBattery NEXUS 48V LiFePO4 battery (15 kWh) — lithium iron phosphate storage with a built-in battery management system (BMS). One NEXUS provides substantial standalone reserve, and multiple units combine to scale capacity as your needs grow.
1 × APEX 10K off-grid inverter — an all-in-one unit for 48V battery systems: 10,000W of continuous split-phase 120/240V output, integrated MPPT solar charge controller, and battery charger in a single chassis.

Is this the right size for you?

This configuration fits workshops, homesteads and properties with demanding peak loads but moderate daily energy use — the 10,000W inverter comfortably starts and runs heavy equipment, while 15 kWh of storage covers overnight and intermittent use.

Size up the storage if you draw on the bank heavily every day or your site sees long overcast stretches: the same system is offered with two or three NEXUS batteries (30 kWh and 45 kWh), and because NEXUS units combine, you can also start here and add batteries later.

Consider the APEX 6.5K version if your loads are lighter — a cabin or backup-circuit application rarely needs 10kW of output, and the smaller inverter costs less.

Specifications

Item	Specification
Battery	1 × BigBattery NEXUS, 48V LiFePO4, 15 kWh
Battery chemistry	LiFePO4 (lithium iron phosphate)
Battery management	Built-in BMS with cell monitoring and protection
Inverter	APEX 10K all-in-one: 10,000W continuous split-phase 120/240V output
Solar charging	Integrated MPPT solar charge controller (solar array sold separately)
Battery charging	Integrated charger in the APEX 10K
System voltage	48V
Expansion path	Additional NEXUS batteries can be combined; 30 kWh and 45 kWh kit configurations are also available

Warranty & support

Battery: the NEXUS is covered by BigBattery's 12-year manufacturer warranty, backed by lifetime USA-based technical support. Inverter: the APEX 10K carries a 5-year limited manufacturer warranty.

Common questions

Why choose the 10K inverter with only one battery?

Peak power and stored energy are separate questions. If your equipment needs high wattage in bursts — motor starts, welders, compressors, multiple 240V circuits — but your total daily consumption is modest, a big inverter with a single battery is the right-sized answer, and the battery bank can grow independently later.

Can I install this myself?

Placing the battery and mounting the inverter are owner-level tasks, but the AC side — panel interconnection, grounding, bonding and code compliance — is work for a licensed electrician and typically requires a permit and inspection. Have your electrician review the system before ordering.

Does this kit include solar panels?

No. The MPPT input is ready for an array, but panels, racking and array wiring are sized to your site and sold separately.

How does the battery handle cold weather?

LiFePO4 loses usable capacity in the cold, and charging below freezing damages cells. Keep the NEXUS in a space that stays above freezing.