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EG4

EG4 WallMount 314Ah Indoor Battery | 48V | 16 kWh | UL9540A | Self-Heating

SKU FEWMT-48161-G1

Regular price: $3,784.99

Regular price: $3,784.99

✅ 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.

Quantity

OffGrid Horizon Family Owned and Operated

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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 EG4 WallMount Indoor Battery is a 48V, 314Ah (16 kWh) LiFePO4 home backup battery designed for indoor installation — garages, basements, and utility rooms. It includes self-heating for reliable charging in cold conditions and carries a UL9540A listing, and it pairs natively with EG4 FlexBOSS hybrid inverters. It's the battery used in our FlexBOSS18 and FlexBOSS21 Indoor kits.

Why the WallMount 314Ah Indoor

16 kWh from one unit — enough to carry a household overnight from a single wall-mounted battery
Self-heating cells: the pack warms itself before charging in cold conditions, so an unheated garage in winter doesn't take your charging offline
UL9540A listed — the fire-safety testing building departments look for when permitting residential energy storage
Closed-loop communication with EG4 FlexBOSS hybrid inverters for accurate state-of-charge and coordinated charging
LiFePO4 chemistry with a built-in battery management system (BMS)
Wall-mounted design keeps floors clear; multiple units parallel for 32, 48 kWh and beyond

Who it's for

Homeowners installing storage indoors — especially in cold climates, where the self-heating function keeps winter charging reliable, and in jurisdictions where UL9540A documentation smooths permitting. If your battery must mount outside, choose the WallMount 314Ah All-Weather instead. Complete pre-matched systems are available as our FlexBOSS18 and FlexBOSS21 Indoor kits.

Specifications

Nominal voltage	48V
Capacity	314Ah — 16 kWh
Chemistry	LiFePO4 (lithium iron phosphate)
Certification	UL9540A
Cold weather	Self-heating for below-freezing charging
Communication	Closed-loop with EG4 FlexBOSS hybrid inverters
Protection	Built-in BMS
Expandability	Parallel multiple units for greater capacity
SKU	FEWMT-48161-G1

Warranty

The EG4 WallMount 314Ah Indoor carries a 10-year manufacturer warranty — valid for ten years from purchase or 10,000 cycles, whichever comes first. EG4 requires warranty registration within the first year of purchase (or proof of purchase from an authorized distributor) to keep coverage valid.

Common questions

Why does self-heating matter?

LiFePO4 cells can't be charged below freezing without damage, so an ordinary battery in an unheated garage simply stops accepting charge on cold mornings. The Indoor model heats its own cells first, keeping solar and grid charging available all winter.

Indoor or All-Weather?

Choose Indoor for garages, basements, and utility rooms — you get UL9540A listing plus self-heating. Choose the All-Weather model only if the battery must live outside.

Can I parallel more batteries later?

Yes — additional WallMount units can be added to grow the bank; our kits pair one to three with a FlexBOSS inverter.