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BigBattery

BigBattery ETHOS + EG4 18kPV Hybrid Inverter Kit | 10.24–30.72 kWh | Whole-Home Solar ESS

SKU K0954

Regular price: $7,755.00

Regular price: $7,755.00

✅ 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.

Product variants

Quantity

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 ETHOS + EG4 18kPV Hybrid Inverter Kit is a complete, scalable home energy storage system: stackable ETHOS 48V LiFePO4 battery modules paired with the EG4 18kPV, an all-in-one hybrid inverter that accepts up to 18 kW of solar input and delivers 12 kW-class split-phase AC output. One unit manages solar, battery, grid, and generator power, while the ETHOS tower scales from 10.24 kWh for essential circuits to 30.72 kWh for whole-home coverage.

What's in this kit

1 × EG4 18kPV all-in-one hybrid solar inverter — up to 18 kW of PV input, 12 kW-class split-phase 120/240V output, with grid-tied, off-grid, and battery-backup operating modes in a single wall-mounted unit
Your choice of 2, 3, 4, or 6 × BigBattery ETHOS 48V 5.12 kWh LiFePO4 modules — 10.24, 15.36, 20.48, or 30.72 kWh of stackable, tower-style storage
Closed-loop communication between battery and inverter for accurate state-of-charge reporting and coordinated charging

Choosing your capacity

2 modules (10.24 kWh) covers essential circuits — refrigeration, lighting, electronics, and a few key outlets — through an evening outage. 3–4 modules (15.36–20.48 kWh) carries most households overnight, including well pumps and moderate 240V loads. 6 modules (30.72 kWh) is the whole-home configuration for larger houses, longer autonomy, or heavy solar self-consumption. Because ETHOS is a stacking platform, you can start smaller and add modules as your needs grow.

Key features

Safety-certified battery platform: ETHOS modules are built on UL1973-listed cells with UL9540A-tested design — the certifications building departments look for in residential energy storage
18 kW of solar input — enough headroom for large rooftop or ground-mount arrays, managed by the inverter's built-in MPPT charge controllers
Hybrid operation: solar self-consumption, time-of-use offset, battery backup, and grid interaction from one unit, with generator input supported
Small-footprint tower: modules stack vertically instead of spreading across a wall

Specifications

Battery platform	BigBattery ETHOS, 48V LiFePO4, 5.12 kWh per module
Capacity options	10.24 / 15.36 / 20.48 / 30.72 kWh (2, 3, 4, or 6 modules)
Battery certifications	UL1973-listed cells; UL9540A-tested design
Inverter	EG4 18kPV all-in-one hybrid
Solar (PV) input	Up to 18 kW
AC output	12 kW-class, split-phase 120/240V
Operating modes	Grid-tied, off-grid, battery backup, generator input
Expandable	Yes — add ETHOS modules over time

Warranty & support

Battery: ETHOS modules are covered by BigBattery's 12-year manufacturer warranty, backed by lifetime USA-based technical support. Inverter: the EG4 18kPV carries a 10-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

Which capacity should I pick?

Select your module count from the Battery Configuration menu — the price shown is always for the complete kit (inverter plus batteries). If you're unsure, start with the capacity that covers your essential loads; the ETHOS platform lets you add modules later.

Do I need an electrician?

Yes — a hybrid inverter interconnects with your main panel and, in grid-tied modes, with the utility. Installation should be performed by a licensed electrician, and home energy storage installations are subject to local permitting.

Are solar panels included?

No. The 18kPV accepts up to 18 kW of PV, but panels, racking, and array wiring are sized to your site and sold separately. The system also operates as battery backup without solar.